Help: WOT Pre-Detonation / Knock + Oil Consumption

[Low and Behold]

Ive done research at nauseam for about 9 months. Hell I’ve also seen a couple guys with similar issues lately (@danaldson, @hemantpd1). But I feel like I’ve gone through the entire checklist of possible scenarios here, so its time to ask for some help.

The Car:
07 2.0 Avant (tip). 81k

The (short) backstory:
About a year ago I had my tune installed (GIAC). About a month later I started noticing some pre-detonation, and I was adding a quart about every 900 miles on average. Did my timing about 6 months ago and noticed a CRAZY amount of oil coming out of the IC piping. Ever since then I've been trying to find the source of it. At WOT I will get some hesitation. If I'm really gunning it at low RPM, I will usually get some knock as it builds boost. The car runs perfectly otherwise.

My theory:
The large amounts of oil in my IC piping is being sucked through the intake, causing hesitation, smoke, and ultimately pre-detonation/knock.

Things I've replaced over the past year:
MAF
Coil packs
Plugs every 3k (NGK coppers)
Entire PCV system
VC+VCG
Switched over to a BSH Catch Can
TURBO [headbang]

Am I missing something major? Im sure I left something out - its a lot to remember. Im confident that the pre-detonation is due to the oil being sucked through. Just need to figure out how the hell the oil is making it in there.

[aluthman]

How much oil are we talking here? A small amount is normal. And when you say pre-detonation/knock, how are you determining this? Is it audible or are you looking at timing pull on logs?

[Low and Behold]

- About 1/3 quart
- Audible and verified by local tuning shop. Basically a loud ticking noise accompanied by smoke and loss of power

[Okedokey]

subscribed

[Okedokey]

What is your compression like?

[ShelbyM3]

We haven't tried a compression test. Our theory is that because the oil is pooling in the IC pipes so heavily, that even if the rings were bad, which I don't think they are, the oil will never make it to the IC pipes.
After we replaced the turbo, all was well for about 2 weeks. Now he's got a decent amount of oil back in the IC piping.


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[grassrootz]

subscribed.

[derrek]

compression test just so you know where you're at then check the valve cover for cracks on the underside.

[ShelbyM3]

Valve cover has been changed.


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[Low and Behold]

Compression test coming soon. I highly doubt the rings are responsible, but I want to know what the compression looks like anyways. I don't think its possible (and correct me if I'm wrong please) for bad rings to cause oil pooling in my intercoolers.

Im leaning back toward Valve Cover and PCV system and i have a question about the metal breather hose connected to the turbo: Is it supposed to let oil into the turbo from the valve cover? Mine seems to be letting in a good amount, and over the course of 800-900 miles I feel like it could really add up. mind you I've already replaced this breather hose once with the revision/check valve hose.

Heres a pic

http://i1086.photobucket.com/albums/j457/caseydshore/259D0B5F-3F09-4E39-8EA4-964DD5ED1650_zps2dnvhmq7.jpg (http://s1086.photobucket.com/user/caseydshore/media/259D0B5F-3F09-4E39-8EA4-964DD5ED1650_zps2dnvhmq7.jpg.html)

[onedumslack]

My oil consumption ranges about 1 qt every 1500 miles. And it builds up in the intercoolers just like you have pictured. I have also replaced everything you have and got about 175 compression on all cylinders. I am not aware I have any knocking or pre detonation though. I eventually just gave up chasing the oil loss.

[Low and Behold]

My oil consumption ranges about 1 qt every 1500 miles. And it builds up in the intercoolers just like you have pictured. I have also replaced everything you have and got about 175 compression on all cylinders. I am not aware I have any knocking or pre detonation though. I eventually just gave up chasing the oil loss.

Are you tuned?

I honestly don't care much about the oil loss, but it seems to be causing performance issues. If i wasn't suffering from performance issues I would probably give up as well.

Can anyone shed some light on the metal breather tube pic i posted above? Really wondering if that could ultimately be causing the issue

[onedumslack]

Are you tuned?

I honestly don't care much about the oil loss, but it seems to be causing performance issues. If i wasn't suffering from performance issues I would probably give up as well.

Can anyone shed some light on the metal breather tube pic i posted above? Really wondering if that could ultimately be causing the issue

I'm Apr stage 2+ tuned. I got to the point where I needed to do a leak down test to determine if it's rings or valve guides and then lost interest cause I don't believe it's hurting my performance and I'll be engine swapping soon anyways.

[ShelbyM3]

Are you gonna do a compression test?


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[Low and Behold]

Update, in case this helps anyone -

Took it to a local tuning shop for further diagnosis. They were quite confident that oil filter housing was failing. There were no leaks whatsoever, but apparently it wasn't separating air/oil and just pushing tons of oil up to the VC - through PCV - Through rear breather (see post #10) - into intercoolers - up through intake. A gulp of oil through the intake will basically cut fuel octane and make it run like shit regardless, especially with a tune.

Changed it over the weekend. Most say its a PITA, but I found it surprisingly easy and relatively cheap at $185.

Car feels good right now. Still some slight pre-detonating as residual oil works it way out. Will take the ICs out this weekend to inspect and clean.

http://i1086.photobucket.com/albums/j457/caseydshore/Oil%20Housing_zpsxlewsqbe.jpg (http://s1086.photobucket.com/user/caseydshore/media/Oil%20Housing_zpsxlewsqbe.jpg.html)

[Low and Behold]

Another update in case this can help anyone in the future. The saga continues...

No luck with that oil filter housing. Shop also recommended replacing the valve cover (again) so i did that this weekend with a brand new one. The old one was definitely thrashed so this should help. I also removed the ICs and all piping to deep clean everything and ensure there was no oil (or at least very little) left in the system to get sucked through the intake. Also put in new OE plugs. Still have the same issues with preignition [headbang]

At this point I've decided that I'm definitely chasing TWO issues. I believe the oil consumption issue will now be solved with my third VC. There was no doubt that the old one failed big time after removing it and inspecting it. However, the preignition continues even with all the aforementioned work.

Now I'm starting to wonder if its just not getting enough fuel under boost? Cam follower was changed 8k ago and the old follower looked great. I think its time to refocus my efforts [:/]

[Jake@JHM]

Another update in case this can help anyone in the future. The saga continues...

No luck with that oil filter housing. Shop also recommended replacing the valve cover (again) so i did that this weekend with a brand new one. The old one was definitely thrashed so this should help. I also removed the ICs and all piping to deep clean everything and ensure there was no oil (or at least very little) left in the system to get sucked through the intake. Also put in new OE plugs. Still have the same issues with preignition [headbang]

At this point I've decided that I'm definitely chasing TWO issues. I believe the oil consumption issue will now be solved with my third VC. There was no doubt that the old one failed big time after removing it and inspecting it. However, the preignition continues even with all the aforementioned work.

Now I'm starting to wonder if its just not getting enough fuel under boost? Cam follower was changed 8k ago and the old follower looked great. I think its time to refocus my efforts [:/]

Yea I don't see how an oil filter housing would lead to anything other than an oil leak.

Since you have an FSI car there is a chance you have a failing injector. If the injector is spraying less fuel than it is supposed to, that cylinder heat is going to get way hotter than the rest (lean), thus causing pre-ignition. If the injectors is CONSTANTLY spraying, its going to create severe hot spots in your combustion chamber that would cause pre-ignition and could lead to melting through the piston.

Additionally, both of those could cause your ring gap to expand in that cylinder which can cause cylinder wall scoring and ultimately leading to oil consumption.

[Low and Behold]

oil filter housing - suggested to be replaced by shop. Wasn't leaking, but they thought it might not be separating air/oil and just pushing it all up to the VC. I figured it was worth a shot at that point...

The consumption of oil lies pretty exclusively in my ICs and related plumbing. Correct me if I'm wrong, but bad rings won't put oil into this system? But given the busted seams in my old VC, it was obvious that the PCV was sucking oil straight out of the crankcase and forcing it down into the turbo.

The injectors are a good callout. I was originally thinking HPFP

[Jake@JHM]

oil filter housing - suggested to be replaced by shop. Wasn't leaking, but they thought it might not be separating air/oil and just pushing it all up to the VC. I figured it was worth a shot at that point...

The consumption of oil lies pretty exclusively in my ICs and related plumbing. Correct me if I'm wrong, but bad rings won't put oil into this system? But given the busted seams in my old VC, it was obvious that the PCV was sucking oil straight out of the crankcase and forcing it down into the turbo.

The injectors are a good callout. I was originally thinking HPFP

Oil in the turbo/intercooler is somewhat natural for a journal bearing turbo. Blow by is always going to be present. If it was super excessive then I would look at failing; valve cover, turbo chra, or pcv.

If you are down a quart, you would need to find about a quart or more worth of oil in your intercooler.

What was your though for HPFP? If that was failing you would have a fueling codes. The reason why a failing injector could slip under the radar is that AFR and EGT isn't monitored per cylinder.

[Low and Behold]

Mini bump.

Jake - you were correct on the fueling thought. But theres something Im a tad confused about after taking it to a local shop. After logging the car, they concluded that my fuel pressure is too low @110 mbar. They said it should definitely be higher and that its likely causing it to run lean to the point of preignition... They asked if I've changed my cam follower and inspected the cam. Yes, i have (7k miles ago). I can't recall EXACTLY what the follower looked like, I was just relieved that it didn't have a hole in it and wasn't caved in. They're willing to wager that i need a new cam.

Anyway, i ordered an HPFP stud kit and a new follower as i will check this weekend. If all looks good then ill be back to square one [headbang]. I might just remove my tune (I don't have a stock program) if everything looks good. Id rather drive bone stock and not explode

Whats the high fuel pressure supposed to be at? They claimed that it should be 125, but i can't find anything to confirm it. Everything i find says 110 exactly.

[p0isin]

I thought 110 - 115 bar was normal for a stock tune. You shouldn't see large impact to lambda unless you are >15 bar too low on fuel pressure anyways as the ecu should increase injector open time to compensate. Log actual vs requested fuel pressure to see.

[Jake@JHM]

110 is correct for a stock car.

[Low and Behold]

Well the tune is asking for 120 so theres the issue. Grrr....

might just replace the follower and reinspect the cam. if all looks good then the tune will have to be removed [poop]

[Low and Behold]

Just for reference, whats the OEM hpfp capable of in terms of pressure?

[p0isin]

Maybe I missed it just skimming this page of your thread but is the car stock or tuned? A tune can request 120+ bar and some of the early b7 a4s had a PRV valve around that number which would cause it to open and dump fuel pressure too early.

[Low and Behold]

Maybe I missed it just skimming this page of your thread but is the car stock or tuned? A tune can request 120+ bar and some of the early b7 a4s had a PRV valve around that number which would cause it to open and dump fuel pressure too early.

Its ok to skim [:D]

Yes i am tuned - GIAC

[Okedokey]

What about modding the PRV to a RS4 one to increase the rail pressure capacity. Also, S3 injectors?

[Low and Behold]

Ive thought of this, but wondered why the stock PRV isn't putting out more pressure in the first place.

[martin0079]

Check LP fuel pressure at WOT. Make sure you are getting the 6bar. The relief valve opens if there is too much pressure on the HP side. Without seeing the log no one on here can say if the PRV is lifting causing you to stay at 110bar. IIRC and someone correct me if this isn't correct early 2.0t PRV was 116bar late was pushed to 120bar and the RS4 is 125bar.

No mention of carbon cleaning with the amount of oil in the intake you more than likely need to get this done. Also any pressure testing of the intake system vacuum leaks cause these kinds of problems.

[Jake@JHM]

Check LP fuel pressure at WOT. Make sure you are getting the 6bar. The relief valve opens if there is too much pressure on the HP side. Without seeing the log no one on here can say if the PRV is lifting causing you to stay at 110bar. IIRC and someone correct me if this isn't correct early 2.0t PRV was 116bar late was pushed to 120bar and the RS4 is 125bar.

No mention of carbon cleaning with the amount of oil in the intake you more than likely need to get this done. Also any pressure testing of the intake system vacuum leaks cause these kinds of problems.

Early 116bar
Late 126bar
RS4 136bar

[Low and Behold]

So my tuning shop here is certain that i need a new intake cam.

We think that the PO had a blown follower (for who knows how long), replaced the follower, but damage was likely done at that point. So this got me thinking...

I called my local Audi dealership so they can verify the cam/hpfp warranty. Im still within the timeframe and only have 85K. The service writer told me that if I'm having fueling issues i can pay them to inspect the pump, and if they find a hole in the follower everything will be replaced under warranty. Problem is I replaced my follower about 8-10k ago so I doubt its warn through, but who knows. I will check it on saturday.

If I see cam damage but the follower is ok, I'm going to find a blown follower and slap it on there, drive to audi, and ask them to inspect. I will have to uninstall my tune first for sure though

If any of the previous posters have thoughts on this let me know. Ive read through the extended warranty thread and it seems like different dealerships handle it differently. My dealership said for certain if they find a hole in the follower everything would be replaced.

[pezgoon]

So my tuning shop here is certain that i need a new intake cam.

We think that the PO had a blown follower (for who knows how long), replaced the follower, but damage was likely done at that point. So this got me thinking...

I called my local Audi dealership so they can verify the cam/hpfp warranty. Im still within the timeframe and only have 85K. The service writer told me that if I'm having fueling issues i can pay them to inspect the pump, and if they find a hole in the follower everything will be replaced under warranty. Problem is I replaced my follower about 8-10k ago so I doubt its warn through, but who knows. I will check it on saturday.

If I see cam damage but the follower is ok, I'm going to find a blown follower and slap it on there, drive to audi, and ask them to inspect. I will have to uninstall my tune first for sure though

If any of the previous posters have thoughts on this let me know. Ive read through the extended warranty thread and it seems like different dealerships handle it differently. My dealership said for certain if they find a hole in the follower everything would be replaced.

Everything I've read says that same thing, they will also do it for certain codes if you push them to, the trouble is having the hole or the codes!

[Low and Behold]

Hell yes!

Now, anyone have a blown follower laying around ? [:D]

[pezgoon]

Lol I know mickmerr did a few weeks ago, I changed it for him! Maybe you can try asking if he's still got it and can send it to you! Shit was blown clear through

[Low and Behold]

Sweet. Sent him a PM... Hopefully he still has it

[Low and Behold]

Updating this for the helluvit. Hoping it could help folks in the future.

1. VC changed. Oil consumption fixed [up]
2. Uninstalled the tune in preparation to have Audi "check the cam/follower" and the car ran great.
3. Audi changed the cam/pump/follower under warranty.
4. Reinstalled the tune. Car ran better for sure, but still some hesitation and preignition. Not nearly as much as before

SO, at this point I'm going to do some logging to narrow it down a bit further. Definitely feels fueling related still. My thoughts are either PRV or one of the pressure sensors.

Will post logs when I have them

[derrek]

Updating this for the helluvit. Hoping it could help folks in the future.

1. VC changed. Oil consumption fixed [up]
2. Uninstalled the tune in preparation to have Audi "check the cam/follower" and the car ran great.
3. I was able to use some resources and magic to get Audi to change the cam/pump/follower under warranty.
4. Reinstalled the tune. Car ran better for sure, but still some hesitation and preignition. Not nearly as much as before

SO, at this point I'm going to do some logging to narrow it down a bit further. Definitely feels fueling related still. My thoughts are either PRV or one of the pressure sensors.

Will post logs when I have them


If you're still getting oil in the IC pipes compression test and if thats bad leak down test. I've had blow by fill my catch can before, it could be sending it all threw your pcv system that reroutes back to the turbo inlet.

For fuel, log your LPFP I bet its not keeping up with whats requested and causing you to run lean.

[Low and Behold]

As stated above, the changing the VC fixed the consumption...

Will log LPFP for sure


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[Wharfbanger]

I was interested to find this thread. I have owned my 2008 2.0T Quattro for 2 months, 6MT. 93,000 miles. Went APR stage 1 a month ago. I have been getting some detonation in 4th after flooring it on steep uphill from about 1800-2000rpm. Definitely detonation, no doubt about it. At the top of the hill I pulled over and did a U-turn. The engine missed a little and belched some smoke as I pulled away in 1st. Then, it ran fine as I headed home without loading the engine or attempting to make it detonate.

Worried, I did some googling and read that carbon deposits in the cylinder can cause detonation. The theory is that carbon builds up and raises compression and this causes detonation. I am aware that the 2.0 TFSI engine is prone to carbon deposits.

One of the recommendations was an Italian tune up. Basically take it out for a spirited drive, enough to hit the red line a bit. All the heat and energy will hopefully dislodge the carbon. To cut a long story short I did the "tune up". I repeated the uphill stretch in 4th and it would appear the problem is solved - same fuel, no detonation.

I have done a couple of tune-ups now and both times it has fixed the detonation issue - for a time. Oh, the car uses a lot of oil - my last quart went in 540 miles.
So I was very interested in your comments that oil through the intake could be lowering the octane and causing detonation. This would potentially explain both issues. Does anyone have any suggestions?

[Okedokey]

What fuel you using?

[Wharfbanger]

What fuel you using?

Always 93. I have tried fresh tanks so I think I can eliminate fuel as a cause for the detonation.

[Okedokey]

Ok, carbon build up, spark plugs, fuel pressures... i guess you've already looked at these.

[Wharfbanger]

Ok, carbon build up, spark plugs, fuel pressures... i guess you've already looked at these.

I have changed the plugs/coils and O2 sensor. Have not checked fuel pressure, but don't think detonation caused by faulty injectors or a faulty fuel pump would be "fixed" by an Italian tune up. If it is carbon build-up, then I could see how that could be blown out. Or, as has been suggested in this thread if oil were accumulating somewhere and then entering the combustion chamber, that might also be blown out by the Italian tune up. I like the idea that my oil is escaping the engine in this way, rather than around worn rings, because it might be repaired more cheaply. Not sure how though as I am not a mechanic. Maybe I have a cracked valve cover? Or something faulty with the turbo's lubrication system is causing oil to accumulate, then be blown into the chamber under load? Any ideas?

[Low and Behold]

I have changed the plugs/coils and O2 sensor. Have not checked fuel pressure, but don't think detonation caused by faulty injectors or a faulty fuel pump would be "fixed" by an Italian tune up. If it is carbon build-up, then I could see how that could be blown out. Or, as has been suggested in this thread if oil were accumulating somewhere and then entering the combustion chamber, that might also be blown out by the Italian tune up. I like the idea that my oil is escaping the engine in this way, rather than around worn rings, because it might be repaired more cheaply. Not sure how though as I am not a mechanic. Maybe I have a cracked valve cover? Or something faulty with the turbo's lubrication system is causing oil to accumulate, then be blown into the chamber under load? Any ideas?

Thread jacker! [>_>]

Carbon build up? Sure. But if you're not getting enough fuel the same thing could happen. Too much air and not enough fuel would make things a bit too hot, thus combusting early.

Valve cover is easy to check. If you're going through that much oil its either the VC or your turbo seals. Pull your lower IC pipes and see how much oil comes out. Im guessing there will be a ton

[Wharfbanger]

Thread jacker! [>_>]

Carbon build up? Sure. But if you're not getting enough fuel the same thing could happen. Too much air and not enough fuel would make things a bit too hot, thus combusting early.

Valve cover is easy to check. If you're going through that much oil its either the VC or your turbo seals. Pull your lower IC pipes and see how much oil comes out. Im guessing there will be a ton

Guilty! Thanks for the reply and advice. Will definitely check the IC pipes and VC.

I understand how running lean will cause detonation. However, if it is fuel supply (fuel pump or injectors) then I don't think the Italian tune up would have helped - which it really seems to have. Let me know if you try the Italian tune up to see if it will stop your detonation..it seems like we have had some similar issues.

Thanks again!

[Low and Behold]

Ive been driving the crap out of it lately. Its honestly been running quite well when I'm abusing it. Its just those times I'm cruising on the freeway in high gear/low rpm and start to give it throttle that it will hesitate or detonate. Doesn't happen all the time now, but its a issue I'm obsessing over. [rolleyes]

Just bought a house so priorities are 'a changing, but Im going to log low pressure this weekend and see if thats whats happening (i think it is)

[Wharfbanger]

Ive been driving the crap out of it lately. Its honestly been running quite well when I'm abusing it. Its just those times I'm cruising on the freeway in high gear/low rpm and start to give it throttle that it will hesitate or detonate. Doesn't happen all the time now, but its a issue I'm obsessing over. [rolleyes]

Just bought a house so priorities are 'a changing, but Im going to log low pressure this weekend and see if thats whats happening (i think it is)

Congrats on your house purchase.[:)]

This also sounds similar to what I have been experiencing. So I will be cruising gently for an hour or so (kids in the car), then power up a long steep uphill, pedal down in 4th from low speed, really loading up the turbo from about 2000 rpm. That's when I get the rattle, power loss and smoke. Then I drop off the kids, give it a blow out, try the same uphill stretch she is perfect. I can imagine all the gentle driving is allowing the oil to accumulate, then it gets blown into the chamber when I hold the boost at maximum. BTW I can understand the whole obsessing thing, these are really well made cars with a ton of personality, you kind of fall in love with them and want them to run perfect. They really are more like Italian cars in some ways, or maybe a mistress - fun but can give you some trouble [:)].

[Low and Behold]

yeah that "rattle" you're hearing is likely the pre-detonation, then you'll see some smoke. Same thing here.

Ill update this weekend after I do some logging. Im thinking its either LPFP related (seeing as my HPFP is brand new) or PRV related. I wonder if my PRV is just lifting too early to maintain fuel for my tune

[Wharfbanger]

Thread jacker! [>_>]

Carbon build up? Sure. But if you're not getting enough fuel the same thing could happen. Too much air and not enough fuel would make things a bit too hot, thus combusting early.

Valve cover is easy to check. If you're going through that much oil its either the VC or your turbo seals. Pull your lower IC pipes and see how much oil comes out. Im guessing there will be a ton

So I checked the turbo inlet by pulling off the rubber hose from the air intake. I could see a small amount of oil pooled where the PCV breather connects to the turbo inlet. However the inlet pipe itself seemed dry and clean downstream where it bends toward the turbo. Wonder if this small amount of oil is sufficient to warrant a new valve cover?

[Low and Behold]

Not quite yet. You should still pull your IC pipes and see how much oil comes out. Have you tested your PCVs or anything to make sure they're working?


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[pezgoon]

Have either of you tried seafoaming the intake? Seeing if it helps at all?

Obviously if you are untuned and it doesn't happen it sounds like the tune is causing the car to do something it normally wouldn't... just sayins


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[Wharfbanger]

Not quite yet. You should still pull your IC pipes and see how much oil comes out. Have you tested your PCVs or anything to make sure they're working?


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Still need to look at IC pipes and PCV. Spent a couple of hours tonight reading up on the PCV system, trying to understand how it could lead to excessive oil consumption. Found a good link - Paragraph 3 also suggests to check the IC pipes for excess oil:

http://karmakanix.com/knowledgebase/engines/gas-engines-vw-audi/2-0t-engine-tfsi-fsi-audi-vw/2-0t-oil-consumption/

So I am trying to understand this, please correct me if I am wrong. PCV fails by allowing positive boost pressure from the intake manifold into the crank case. Further, turbo lubrication system and engine crank case are pressure connected. This causes oil in the turbos lubrication system to blow through seals into the exhaust and intake. Result = oil consumption, possibly detonation and oil in the IC pipes?

[Wharfbanger]

Have either of you tried seafoaming the intake? Seeing if it helps at all?

Obviously if you are untuned and it doesn't happen it sounds like the tune is causing the car to do something it normally wouldn't... just sayins


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No way to know as I did the tune soon after buying the car. I agree that the extra boost could aggravate a weak PCV, or many other things..

[pezgoon]

Yes they are known to bring out hidden issues that's why I asked, I'd start with pcv if you haven't replaced it


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[Avant4me]

wow you have all the same issues that i'm having with my 2007 2.0T 6mt avant.

I've replaced a lot of the same things you have.
Just ordered all new PCV and a new valve cover so hopefully that will fix the oil consumption like yours.
I was hesitant on the oil housing but a little reassured since it didn't help you really.

I'm running NGK BKR8E with a stage 2 tune (JHM), HPFP, full turbo back 3". The BKR8E helped with the pre-ignition issues but think carbon build up and a need to clean the fuel injectors might help even further. Looking forward to more of your results

[Low and Behold]

wow you have all the same issues that i'm having with my 2007 2.0T 6mt avant.

I've replaced a lot of the same things you have.
Just ordered all new PCV and a new valve cover so hopefully that will fix the oil consumption like yours.
I was hesitant on the oil housing but a little reassured since it didn't help you really.


Yeah it was weird the shop recommended I do the oil filter housing, but I did it anyway. Ill be curious to see what your valve cover looks like.

[Low and Behold]

Oh and an update on my car (its my thread after all [:D])

Logged high and low fuel pressure this weekend. Holding 110 bar at WOT / LPFP 5 bar basically on the dot. I don't understand this...

To refresh memories - my tuning shop had done some logging back in August and found that the HPFP was "low end spec" at 110bar. Since then, my intake cam/hpfp/follower was done by audi under warranty. So we're dealing with brand new parts here and its still only making 110bar....

Now I might call GIAC to see how much pressure the tune should be requesting. Feels like the tune wants more fuel, but isn't making the pumps put any more pressure out. UGH.

The other thing I found while logging was P0299... This makes me think N75 since I've already updated to the new DV. Plus this feels like it could be the culprit for the hesitation I'm feeling when I'm gassing it in high gear / low rpm. My tuning shop things the "clicking" sound I've been hearing during the hesitations is likely preignition because my tune wants more than 110bar for fuel, but now I'm starting to think they're wrong (though the fact that its still making only 110bar is weird). Im starting to think it really is the wastegate thats making this chatter.

Thoughts?

[Avant4me]

Do you have a hpfp upgrade? JHM internals or APR pump, ect...

[Low and Behold]

negative. I know those will clearly put out more pressure, but shouldn't the stock HPFP go to like 126 bar?

I have stg 1 GIAC tune. Im sure its asking for more than 110, but doubt it would ask for more than 120

[Low and Behold]

Used my Schwaben scan tool last night to do some logging and found a couple of interesting things.

1. with my tune reinstalled, my requested and actual fuel pressure is right in line. However, its still only requesting 110bar for fuel. Im a bit confused as to why the tune would be requesting the exact fuel pressure as a stock ECU would. That said, they're in harmony so I guess thats good.

2. Boost requested is extremely high most of the time - like 2240 mbar (~34psi) but boost actual is like 1400 mbar (~20psi). These numbers are either inaccurate or something is definitely wrong.

I found a P0299 last week and will be boost leak testing and replacing the N75 this weekend to see if it fixes it. Turbo and DV have already been replaced.

Any thoughts are appreciated [az]

[Low and Behold]

Update -

Changed the N75 yesterday and it appears to have fixed the issue. Much smoother while building boost. No chatter (wastage, preignition, or whatever the fvck it could be) under load

@Wharfbanger you tried this yet? Its a $50 part and a PIA to replace, but it could definitely be the issue.

I still would appreciate thoughts on my previous post if anyone has any. Not sure why I'm getting the exact fuel pressure as a stock ECU, just seems weird. Probably going to send GIAC some logs and see what they think

[Avant4me]

Pressure doesn't necessarily mean that the tune isn't putting in more fuel. Pressure can be the same but injectors putting more fuel in. (Pretty sure it works like that)

I changed my vc and looks like my issue is finally resolved

[Low and Behold]

Pressure doesn't necessarily mean that the tune isn't putting in more fuel. Pressure can be the same but injectors putting more fuel in. (Pretty sure it works like that)

I changed my vc and looks like my issue is finally resolved

It must work that way. The increase in power with the tune is obvious, and I don't know how that could happen without more fuel. Just thought it was weird that the numbers were the same.

Good to hear on the VC [up]

[Avant4me]

It must work that way. The increase in power with the tune is obvious, and I don't know how that could happen without more fuel. Just thought it was weird that the numbers were the same.

Good to hear on the VC [up]
You could vagcom your injector duty cycle to find out I believe. Stock might only go 60-75%(just random #s I'm using) where as the tune might go into the 90%s.

[pezgoon]

No the stock hpfp doesn't go to 126, your thinking of the pressure relief valve numbers. The original prv released 116 bar, the later versions released at 126 but not because they increased pressure, they only did this because as the 116 weakened over time, it didn't have a high enough buffer to not start causing issues (like my mothers is right now, giving her low fuel pressure codes when there's nothing left to replace but the prv)

Also the 110bar you measured is reliant on the lpfp, yes it makes that much pressure, the hpfp bumps it up to some stupendous amount of bar (I don't wanna sound like an idiot but it's like 1k bar lol, it's up there) so the hpfp cam follower etc being replaced should have no affect on you getting the 110 bar, that would depend wether your in tank pump is good or bad (the low pressure fuel pump)


Edit: lol didn't notice the next page, he is right that the tune would call for MORE fuel not higher pressure, when you start going higher tunes you need higher pressure but that's to overcome the amount of air being shoved into the cylinder, think of a Diesel engine, these cars work the same way, but with a spark plug. If you want to see where the higher amount of fuel is I would do what is suggested and watch the duty cycle of the injectors and the lpfp more than likely it runs more than it does stock.

Also the 34 psi boost does kind of make sense, I can't remember what tune your using but essentially they are just calling for maximum boost possible, whether or not the car can deliver it. It is like how I used to drive my 11' Mini Cooper, it had an electronic throttle and because of this the car could only be accelerated at the maximum rate the car allowed, so once I would be moving to accelerate I would just floor it and let up when I wanted it to stop because it wasn't actually like the car was being floored, the car would stop once it reached my pedal position but would accelerate at the same rate to get there whether it was floored, 3/4 throttle, 1/2 or 1/4. It's the same concept with the tune asking for 34 psi, a stock turbo cannot give that. 20 psi is what you will see on a stock k03 turbo, so it's the same concept as the mini copper, the car will give you the same as if you were asking 20 psi or 34 psi (essentially) so they ask for a stupid number to make sure it's always making the max possible.

Btw it's probably not good for the turbo life to do that lol

Ps the mini was stick, so it couldn't downshift, an auto that theory wouldn't work/apply to

Pss it was naturally aspirated so it had a much lack in power, I think 125 ft lb or less in a 4300 lb car

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[Brillo]

Based on some of the things that Low and Behold and others have posted above, there may be a misunderstanding about how the HPFP, prv, and ECU (tune) interact. Just like the HPFP, the prv is purely a mechanical device which keeps the HPFP from over pressurizing the fuel rail by lifting or opening to relieve fuel pressure, bleeding off fuel to the low pressure fuel return system. If functioning correctly it is set to relieve pressure at either 116 bar or 126 bar depending upon the model year, later models calling for the 126 bar setting. The prv allows pressurization of the fuel rail to the prescribed level whether at idle or high engine rpm (which I think is why Low and Behold measured the same fuel pressure, post #63). The fuel rail pressure is monitored by the ECU (and can be logged) but not regulated by the ECU. In that regard the ECU or tune really doesn't "request" a fuel pressure. Having said that, certain tunes may be optimized to run at a specific fuel rail pressure. To achieve that pressure you must install the appropriate prv for that tune. The fuel rail pressure is monitored though and can be logged. At 110 bar the rail pressure is running on the low side and you may want to consider installing a new prv as the relief spring in the valve may have relaxed over time.

On the other hand, the LPFP is controlled by the ECU. It's an electric pump and tries to maintain a specific pressure by ECU control of its duty cycle (which as stated can be logged). Problems with the LPFP usually do not manifest at low engine rpm. But at higher rpm the LPFP (at 100% of the duty cycle) may not be able to pump the volume of fuel necessary to feed the HPFP in order for it to meet its volume requirement at the prescribed pressure. This will cause a drop in the fuel rail pressure which the ECU will notice. This could also be caused by a very clogged or restricted fuel filter. The delivery pressure of the LPFP does not affect the ability of the HPFP to pressurize the fuel rail - it's the volume output that matters. It happens that it is much easier to measure and control the output of the LPFP by measuring its pressure output. In other words the delivery pressure of the LPFP does not affect the ability of the HPFP to meet its requirement. In this regard it is not like a two stage air pump where the output of the second stage is a function of the first stage pressure.

At high engine rpm the where the fuel demand is high, cutting or missing (fuel starvation) may occur for a number of reasons related to the fuel pumps and prv. If the prv is malfunctioning by regulating at too low a pressure that will cause the fuel injectors to max out on their duty cycle, a function controlled the the ECU. Also, if the LPFP cannot deliver the fuel volume needed by the HPFP to pressurize the fuel rail at the prescribed level this will hinder the ability of the HPFP to deliver the correct volume of fuel at the prescribed pressure again causing the injectors to max out on their duty cycle. Of course the situation is exacerbated by a tune where the higher boost pressures require even more fuel necessary to meet the stoichiometric air/fuel ratio for optimal combustion (as monitored by the oxygen sensor).

Sorry to be so wordy L&B as you seemed to have found the source of your problem. If others disagree with the above please let us know.

[pezgoon]

That is an awesome in depth explanation and better than mine, only thing I'm curious about more info on the prv, does it act as a mechanical valve to set the pressure, or simply as a pressure relief to prevent overpressure? As from what I've read before it is only to prevent overpressure and the pressure is regulated electronically (from the ecu to the lpfp) is this true that it is only to prevent overpressure or does it mechanically regulate the pressure?


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[Brillo]

I may be wrong but it is my strong understanding that it is purely a mechanical valve which regulates fuel rail pressure merely by relieving any over pressure output of the HPFP. It does this by bleeding of fuel pressure in excess of the prv set pressure. I believe it works in a fashion very similar to the valve on the pressure cooker your mother may have used in the kitchen to cook veggies. It maintained steam pressure in the pot by relieving excess steam to the atmosphere.

[pezgoon]

Ah alright, I always thought the prv was in between the lpfp and didn't realize that it was after the hpfp

But it isn't used to regulate the pressure as that is done electronically, that is done on the hpfp through the fuel regulator (the top electrical part of the hpfp, where as the lower part is the low pressure sensor)

The prv is only an overpressure device to protect the system from blowing up as 110 bar is a shitload of pressure (1500 psi)

It is just that they went to 126 because of the springs relaxing and releasing too soon making the car give a low pressure cel like my mothers car, so it gave the prv a larger buffer zone allowing it to wear out without causing issue

Good explanation though more in depth than mine


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[Brillo]

pezgoon Yes, the prv is on the high pressure side of the HPFP and I'm not sure why they went to 126 bar. The HPFP is capable of developing very high pressures. Some higher stage tunes require 145 to 165 bar prv. But wow, your other questions made me realize that my explanations above (post #66) were way oversimplified and in some cases just plain misleading. Apologies. I do not have a complete understanding of the fuel pressurization system because it's pretty complicated, so let me be a little more detailed so I don't get crucified by more knowledgeable members. I believe that the prv does in fact protect the high pressure side of the system as you say but also comes into significant play during high fuel demand periods, that is at high boost pressure and higher rpm. I stated that there is no requested fuel pressure but there is in a way. You noted the two electrical connections on the HPFP, one on the front side and the other on the right hand side. The one on the front is a pressure sensor. As I stated before the output of this sensor that can be logged and can trip a code if it is too low. It can provide information useful to the ECU too. The other electrical connection is to a solenoid valve. It opens to allow fuel from the low pressure side of the HPFP into the pump and then closes during pressurization (upstroke of the pump piston). It also keeps the maintains the high pressure when the engine is turned off. (The schrader valve on the HPFP bleeds that off.) Based on fuel demand the solenoid valve can be modulated to some extent by the ECU to control the fuel pressure in the rail to values lower that the prv setting. I believe that this occurs during low fuel demand conditions such as during engine idle. I do not know if this function can be logged but suspect it can.

The complexity of this system occurs in an attempt to control pressure based on the fuel injector pulse timing relative to crankshaft position and fuel demand. For example, at idle the injector pulse occurs much earlier in the cycle perhaps as early as the intake stroke where the cylinder pressure is low so fuel pressure needn't be at its max value. Under conditions of boost and higher fuel pressure demand the solenoid is actuated to allow maximum pressure to the fuel rail, where the injector pulse occurs during high cylinder pressure - the compression stroke. This is where the prv is controlling the rail pressure. All this is done to optimize the interrelationship between fuel economy, emissions control, and engine power .

So to be fair to some of the issues raised in this thread regarding the fuel delivery system I suppose there is a possibility that either the pressure sensor or the solenoid valve could malfunction. This is where logging the fuel pressure would be very helpful. From the fuel tank to the injectors the possibilities are: faulty LPFP, clogged fuel filter/fuel lines, bad fuel pressure sensor, malfunctioning solenoid valve, faulty prv, worn cam lobes and/or broken cam follower. I do not know if the fuel pressure fuel sensor and the solenoid can be replaced independent of replacing the entire HPFP. If memory serves, I believe some folks have replaced the pressure sensor though.

[Low and Behold]

Brillo & Pezgoon - thanks for the clear explanations. Good shit!

I guess I was fixated on the fueling all along because my local (and extremely reputable) tuning shop was "willing to wager" that I had a bad intake cam and that was causing the "preignition" issue (audible clacking sound under load that they determined was preignition because they thought that 110bar rail pressure was too low). Turns out it wasn't. I had changed my cam follower a year ago before I realized that my car was well within warranty. So a month ago I removed the HPFP and inspected the cam - light scoring - wondering if the PO may have eaten through a follower and just swapped in a new one. Tip of the HPFP looked fine too. I was stumped and figured I might as well source a blown follower, swap it in and drive it to the dealership. Long story short, Audi replaced everything. I can rule those parts out of the equation...

After logging boost numbers and watching how shaky boost was @ low RPM, I started to turn my attention that way. It really struggled to hit boost and would start making that horrible clacking noise (previously thought of as preignition). With a recent P0299 code to boot, I figured the only thing I hadn't previously changed in relation to that code was the N75 (already had done Turbo, DV, Checked for boost leaks). I assumed the valve was fvcked and not controlling the wastegate properly.

So far so good. My car actually feels a little less powerful but much smoother under load. Seemed like in the past it would struggle so hard to build boost, start making that clacking noise, then it would hit boost at higher RPM like a rocket. Now its much smoother throughout. We'll see how long it lasts

The relationship between PRV, HPFP, Rail Pressure, etc does seem a bit complicated. I know the PRV is purely mechanical, and in my case it must be lifting @ 110 to maintain that pressure. Ill probably swap in the RS4 PRV when I do a carbon cleaning this spring. Im taking a weekend off from this thing. Wife is getting a bit annoyed with how much time I've put into it without much reward

[Wharfbanger]

Update -

Changed the N75 yesterday and it appears to have fixed the issue. Much smoother while building boost. No chatter (wastage, preignition, or whatever the fvck it could be) under load

@Wharfbanger you tried this yet? Its a $50 part and a PIA to replace, but it could definitely be the issue.

I still would appreciate thoughts on my previous post if anyone has any. Not sure why I'm getting the exact fuel pressure as a stock ECU, just seems weird. Probably going to send GIAC some logs and see what they think

Sorry for the slow response.

Recap: 2008 a4 2.0.t MT with 94,000 miles. Intermittent detonation and smoking under heavy load on acertain steep hill from low rpm in 4th gear. No more detonation on this hill for a while after an Italian tune up. Excessive oil consumption - 450 miles per quart. Jerky take off from stop, like a hesitation in first or second gear from low rpm before boost builds. This has had me wondering if I loosing the knack of smooth take offs in a MT!

Update: checked IC pipes, collected about 1/3 quart, then another 1/4 quart 400 miles later. Replaced PCV 200 miles ago, too early to comment on oil consumption.

Out of interest, removed circular cap from old PCV. Diaphram intact but a bit stiff, not supple. Blew forcefully through the intake manifold port on PCV and the valve functioned normally (snapped shut). Gently blew and sucked in rapid succession, and the PCV malfunctioned (did not block my breath).

Current hypothesis: low boost might have been pressurizing crank case (via faulty PCV), causing oil to blow through the turbo seals to the intake (collecting in IC piping, and passing through combustion as vapour). This causes excess oil consumption.

Under heavy boost, the PCV functions correctly.

When enough oil accumulates in the IC, a full boost situation (steep hill in 4th) causes a slug of oil to be blown into the cylinders, lowering octane, causing detonation, and smoking.

Finally, the low-boost PCV malfunction might have been the cause of the hesitance and jerky starts; low boost pressure at take-off is lost to the crank case, then suddenly builds after the valve snaps shut. Not sure about this, but the car does seem to be smoother off the line since I replaced the PCV. No more detonation on the hill. I should know how the oil consumption is going on a week or so...

[Wharfbanger]

Not quite yet. You should still pull your IC pipes and see how much oil comes out. Have you tested your PCVs or anything to make sure they're working?


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Checked the IC pipes a couple of times. Lots of oil drained. Seems they are filling with about 1/3 quart every 500 miles (I am using a full quart every 500 miles).

Also, I can see some fresh oil where the rear PCV pipe connects to the TIP, so it looks like oil is getting sucked into the turbo from the VC.

Changed the PCV 500 miles ago and can confirm I am still consuming the same amount of oil.

Time to do the VC?

[Low and Behold]

Absolutely.


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[Okedokey]

So mate, what fixed it in the end? N75?

[Low and Behold]

It seemed to for about a week or so, now it's right back to the same old shit. I have a feeling it's my lpfp. I don't experience issues at higher rpm, just on the low end.


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[Okedokey]

Keep at it mate, I have a similar issue. I am thinking the waste gate actuator is a bit weakened, contemplating adding springs to tight up.

[Low and Behold]

Well well....

I left work today and the car was just running horribly. Felt like I was hauling a trailer or something, just super sluggish especially at low RPM.
Scanned the car for codes when I got home, praying that something came up. Alas, P310B

I suppose this strongly points to the LPFP itself, right? I changed my fuel filter about a year ago, so I don't think its that. Might as well change it again while I'm at it.

Ill of course do some research on here as this is a pretty common code. Thoughts appreciated too

[Denio24]

Well well....

I left work today and the car was just running horribly. Felt like I was hauling a trailer or something, just super sluggish especially at low RPM.
Scanned the car for codes when I got home, praying that something came up. Alas, P310B

I suppose this strongly points to the LPFP itself, right? I changed my fuel filter about a year ago, so I don't think its that. Might as well change it again while I'm at it.

Ill of course do some research on here as this is a pretty common code. Thoughts appreciated too

Did you bother to log blocks 230 & 231? Compare the values requested vs actual. Leaning out is definitely not good. I would baby the engine for now cause you can cause some real havoc with that detonation.

[Low and Behold]

I haven't but I plan to. Just a quick scan tonight. Time is the real "bother"

Im closing on a house tomorrow, but will log the first chance i get.

[Denio24]

I haven't but I plan to. Just a quick scan tonight. Time is the real "bother"

Im closing on a house tomorrow, but will log the first chance i get.

I had similar issues, in fact I created a similar thread before you titled something like "clicking upon acceleration". I'm 99% sure now that it was detonation, when at the time I thought it was just wastegate rattle. End result? Cracked ring land - I had to tear apart the engine because it was running like shit. It occurred also when I purchased the vehicle when it was still on a stock tune. Going to JHM stage 2 tune probably made things worse. It may have been due to the carbon buildup that the engine was detonating, but I've also had some erratic fuel cut issues and the fuel pump whining sometimes, and then the whining went away. When I get my build together (currently in the process of installing the engine, it is already fully built), one of the first things I do will be to log the high and low pressure fuel system values requested vs. actual. The same should apply to you. Also check your injector duty cycle and long term fuel trim.

[Low and Behold]

Aw don't tell me that! [o_o] (but thank you for your insight)

Hopefully it helps that I:
1. No longer have a lick of oil consumption, and
2. Dont experience these issues on a stock tune

Sorry you had a near worst-case scenario! Hoping this isn't my case.

[Denio24]

Aw don't tell me that! [o_o] (but thank you for your insight)

Hopefully it helps that I:
1. No longer have a lick of oil consumption, and
2. Dont experience these issues on a stock tune

Sorry you had a near worst-case scenario! Hoping this isn't my case.

What remedied your oil consumption problem?

[Low and Behold]

What remedied your oil consumption problem?

VC.

At this point it really comes down the that P310b. Duty cycle for the lpfp at idle is 63.5% which seems... fine?

[Denio24]

A little high. Best if under 60. Duty cycle isnt the whole story though. You must check pressures under load.

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[Low and Behold]

True. I will log it. I just found drewgold's similar situation here http://www.audizine.com/forum/showthread.php/722007-Getting-P0299-Turbo-Underboost-DTC-No-boost-leak-foud-What-to-check-next (Post 24 and on) Looks like RakkCity had an almost identical issue.


I had a 0299 code that stuck through a new DV, PCV, and all new intercooler piping. Turns out it was a weak LPFP due to an 11 year old fuel filter. Try logging your duty cycle of the LPFP, it should be <55% at warm idle and <70% during pulls. Maybe a bit more during pulls with a tune on it. I also had the P310B code, though, so it might not be the pump in your case, but it is possible for the ECU to pull boost if it doesn't have enough fuel.

I had an underboost code a couple weeks ago and replaced my N75. No more code, but now the P310b.

[Okedokey]

http://wiki.ross-tech.com/wiki/index.php/P310B/012555

Faulty G41 (LP Fuel Sensor), vacuum leak, LPFP going out. Below 70% duty cycle is considered within spec, but I think closer to 55% is what you're looking for.

[Low and Behold]

http://wiki.ross-tech.com/wiki/index.php/P310B/012555

Faulty G41 (LP Fuel Sensor), vacuum leak, LPFP going out. Below 70% duty cycle is considered within spec, but I think closer to 55% is what you're looking for.

Called my trusted service guy at Audi today. Told me they will scan it on Monday and if the code is still there (its stored, but ill check before I take it in) they'll replace it. I ordered the LPFP, but would love to return it if the G41 is the issue.

[Wharfbanger]

Checked the IC pipes a couple of times. Lots of oil drained. Seems they are filling with about 1/3 quart every 500 miles (I am using a full quart every 500 miles).

Also, I can see some fresh oil where the rear PCV pipe connects to the TIP, so it looks like oil is getting sucked into the turbo from the VC.

Changed the PCV 500 miles ago and can confirm I am still consuming the same amount of oil.

Time to do the VC?


Just to finish my story, I replaced the valve cover and my oil consumption is now low. Perhaps 0.25 of a quart at 1600 miles. The only confusing factor is that I changed my oil to Rotella T6, and have noticed that my oil consumption has been improving steadily with every new quart I have added. After the first quart it went from 450 mile/qt to 750/qt, then from 750 to 1500 miles/qt (2nd qt, and new valve cover). I recently added my 3rd quart of Rotella, and am currently at 1600 miles with only a small drop in the dipstick!

So I am unsure if its the oil or the new Valve Cover. Maybe both..

[Brillo]

Glad you seem to have solve the oil consumption problem. Although I'm surprised that you needed to add a quart after the valve cover change, I really doubt that it's the oil, but your description of when you added the 3rd quart of oil is a bit confusing. Rotella T6 has no magic over any other quality synthetic oil.

[JetG0ld]

I've got similar issues on my car. When I start it, it sputters a small bit and seems to take an extra crank or two to turn over. Having just picked this car up with 84k on it, i'm going to start by putting new plugs in, doing the BSH PCV Revamp, new battery, and do a compression test. Also when the car is at lower RPMs it seems to run a little rough. I know the 2.0 is a bit more finicky than my 1.8T so I didn't think too much of it. Also, I assume I should consider doing a carbon cleaning as well. Plus I'll check the cam follower (its a 2008 MY though so hopefully all is well there).

[garybone211]

If you think it could be carbon build up on valves theres couple videos showing how to pull the intake off and clean the tops of the valves and it seems pretty straight forward if you want to do it yourself or you can try a can of seafoam spray straight into the throttle body, loosen the carbon then try that italian tune up. And if you thinks it a fuel problem, you could get your injectors cleaned. Ive seen places say they clean injectors for $20 an injector and if you pull them out yourself then its only $80ish to get them cleaned.

[Low and Behold]

If you think it could be carbon build up on valves theres couple videos showing how to pull the intake off and clean the tops of the valves and it seems pretty straight forward if you want to do it yourself or you can try a can of seafoam spray straight into the throttle body, loosen the carbon then try that italian tune up. And if you thinks it a fuel problem, you could get your injectors cleaned. Ive seen places say they clean injectors for $20 an injector and if you pull them out yourself then its only $80ish to get them cleaned.

Nothing will truly clean carbon aside from a manual cleaning. Sea foam is more of a "preventative" measure, and even that doesn't work well. Plus you'd have to change your plugs every time you run seafoam through the intake. Just an FYI

[KillerQuattro]

Wait, was there ever a resolve to OP problem? Interesting thread, no conclusion..

[Low and Behold]

Wait, was there ever a resolve to OP problem? Interesting thread, no conclusion..

Not as of yet. Carbon clean this weekend. Will report back after that. Im wondering if either the carbon buildup is horrible, or maybe a leaky injector. Possibly both. Either way, its getting cleaned.

[KillerQuattro]

My vote is on the LPFP..

And wouldnt you know it, Im getting mine swapped out today! ..Changed the fuel filter out last month, and followed was a P0089. Considering my mileage (150k), and the fact that I have replaced the HPFP, filter, and had a recent carbon cleaning among a ton of other maintenance, I suspect my LPFP duty cycles are out of spec.. It definitely seems to be one of those common failure points at this age..

[Low and Behold]

Hope that fixes it for you. I'm only at 90k. I've done tons of logging on mine, and all things fuel related are good at this point. Who knows... I might just replace it anyway soon but haven't felt like spending $200 on one when mine appears to be working properly.


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[KillerQuattro]

Hope that fixes it for you. I'm only at 90k. I've done tons of logging on mine, and all things fuel related are good at this point. Who knows... I might just replace it anyway soon but haven't felt like spending $200 on one when mine appears to be working properly.


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Well true you are at 90k, and I'm at 150k.. But, we both own a 2007. Gas has been sitting in my tank just as long as it has in yours. Mileage is NOT the only factor.. Heat, fuel quality, time are also variables to consider.

Also, you said your duty cycle is at 63.5%, when it should be closer to 55%(at idle). That doesn't exactly tell me you LPFP is "working properly". It tells me that the part is functioning, but in a somewhat degraded way, enough to cause your issues, but not enough to be super obvious..

Good luck!

[Low and Behold]

Well true you are at 90k, and I'm at 150k.. But, we both own a 2007. Gas has been sitting in my tank just as long as it has in yours. Mileage is NOT the only factor.. Heat, fuel quality, time are also variables to consider.

Also, you said your duty cycle is at 63.5%, when it should be closer to 55%(at idle). That doesn't exactly tell me you LPFP is "working properly". It tells me that the part is functioning, but in a somewhat degraded way, enough to cause your issues, but not enough to be super obvious..

Good luck!

I know mileage isn't the only factor. Didn't say it was. Been on this forum for 11 years and have at least learned that haha. Its still delivering proper pressure. If my lpfp duty cycle was @ 70% or above, then yes, I would have already replaced it. Its a relatively simple job.... plus I need to clean the carbon and injectors anyway so thats happening first.

And shouldn't you at least check your duty cycle before you swap out your LPFP. You said you "suspect" the duty cycle is high, but if you can't confirm it then you're just playing parts-darts.

One thing at a time here. Parts darts can get expensive.

[KillerQuattro]

I'm curious what you find during the carbon clean. The injectors are definitely still a possibility.. Are you cleaning the injectors yourself?

Degraded LPFP is my suspicion, as well as my mechanics diagnosis..

So, I went with replacing it. After doing lots of reading, I saw that my remaining issues were so similar others, with LPFP as the fix. Most everything else fueling related has essentially been cleaned, upgraded, or replaced other than the LPFP, so its basically all that was left.. And you're absolutely correct, parts darts is very expensive.. I dont want to waste my money either, but at this point, I feel its not a bad bet.

I was hoping for a bigger improvement from my Carbon Clean(Walnut Blast) than I experienced. Especially considering I was at 135k, with a ton of nasty buildup..

[Low and Behold]

I'm curious what you find during the carbon clean. The injectors are definitely still a possibility.. Are you cleaning the injectors yourself?

Degraded LPFP is my suspicion, as well as my mechanics diagnosis..

So, I went with replacing it. After doing lots of reading, I saw that my remaining issues were so similar others, with LPFP as the fix. Most everything else fueling related has essentially been cleaned, upgraded, or replaced other than the LPFP, so its basically all that was left.. And you're absolutely correct, parts darts is very expensive.. I dont want to waste my money either, but at this point, I feel its not a bad bet.

I was hoping for a bigger improvement from my Carbon Clean(Walnut Blast) than I experienced. Especially considering I was at 135k, with a ton of nasty buildup..

I do everything myself [:D]

Ask your mechanic what your injector duty cycle is/was. If that fixes it for you then I'd like to know, and compare your numbers with mine.

And I'm right there with you - if this carbon/injector clean doesn't fix the issues (needs to be done anyway) then I'm ordering a new LPFP. Its bound to fail at some point if it already hasn't started.

[Okedokey]

Have you got VCDS mate?

[Low and Behold]

Have you got VCDS mate?

No mate! [emoji24]

But I do have a shwaben scan tool that's pretty useful. Just a pain to log multiple things at the same time.

[Low and Behold]

Also I figured I would update this as I've finished the carbon cleaning / injector cleaning / seals / thermostat while I was in there since mine was leaking. Basically - it went well. Cleaned it by hand with the JHM "kit" which basically consists of a shit wire brush drill attachment and some picks (tools I didn't have before).

Some before:
(Valves open on this one)

https://uploads.tapatalk-cdn.com/20170709/a996ec098e7279b3db86ec2908622916.jpg
https://uploads.tapatalk-cdn.com/20170709/f9f637e91cacb2d57a5d15638fc1712c.jpg

Some after:

https://uploads.tapatalk-cdn.com/20170709/9151efa6216ecc6ea1efd82067758174.jpg

Cleaned/new seals for injectors:

https://uploads.tapatalk-cdn.com/20170709/bf84d3ce6671396cd2f483cbb0da6346.jpg

So far the results are pretty positive. I wasn't expecting a huge difference immediately. Idles smoother and my issue(s) haven't come back, but I won't hold my breath. Drove it for about 30 miles pretty hard. Gave it every opportunity to act up but it behaved. Again, time will tell, and I should have a good idea in the next week or two. The LPFP is in my ECS cart right now just in case...

Some notes -

The wire brush drill attachment I got (and I'm assuming all wire brushes in this case) deteriorated pretty quick, resulting in a ton of wires hanging out in the valve ports... I used a magnet and a shop vac to get all of them out, but it still made me pretty uneasy. I made better use of the picks and just took my time / drank a few beers. Next time I will media blast that shit.

https://uploads.tapatalk-cdn.com/20170709/26734aeb728d686ec3add1e8abdeeb11.jpg

Also the car smoked like crazy when I got it started up. Smelled horrible. I'm assuming this is from a small amount of cleaning solution making it's way into the combustion chamber. Just something that caught me by surprise, though in hindsight it seems obvious

Anyway, I managed not to break anything and it's running well. [emoji1360]

[Okedokey]

Also I figured I would update this as I've finished the carbon cleaning / injector cleaning / seals / thermostat while I was in there since mine was leaking. Basically - it went well. Cleaned it by hand with the JHM "kit" which basically consists of a shit wire brush drill attachment and some picks (tools I didn't have before).

Some before:
(Valves open on this one)

https://uploads.tapatalk-cdn.com/20170709/a996ec098e7279b3db86ec2908622916.jpg
https://uploads.tapatalk-cdn.com/20170709/f9f637e91cacb2d57a5d15638fc1712c.jpg

Some after:

https://uploads.tapatalk-cdn.com/20170709/9151efa6216ecc6ea1efd82067758174.jpg

Cleaned/new seals for injectors:

https://uploads.tapatalk-cdn.com/20170709/bf84d3ce6671396cd2f483cbb0da6346.jpg

So far the results are pretty positive. I wasn't expecting a huge difference immediately. Idles smoother and my issue(s) haven't come back, but I won't hold my breath. Drove it for about 30 miles pretty hard. Gave it every opportunity to act up but it behaved. Again, time will tell, and I should have a good idea in the next week or two. The LPFP is in my ECS cart right now just in case...

Some notes -

The wire brush drill attachment I got (and I'm assuming all wire brushes in this case) deteriorated pretty quick, resulting in a ton of wires hanging out in the valve ports... I used a magnet and a shop vac to get all of them out, but it still made me pretty uneasy. I made better use of the picks and just took my time / drank a few beers. Next time I will media blast that shit.

https://uploads.tapatalk-cdn.com/20170709/26734aeb728d686ec3add1e8abdeeb11.jpg

Also the car smoked like crazy when I got it started up. Smelled horrible. I'm assuming this is from a small amount of cleaning solution making it's way into the combustion chamber. Just something that caught me by surprise, though in hindsight it seems obvious

Anyway, I managed not to break anything and it's running well. [emoji1360]

Use nylon brushes mate, avoids the risk of metal getting in there.

[Low and Behold]

Use nylon brushes mate, avoids the risk of metal getting in there.

What can I say, I love metal [emoji6]

Not sure why JHM supplies the metal/nylon mix ones since they obviously just blow up, but I should have known better. Media blasting next time for sure.

[KillerQuattro]

Nice job! How long did this take you?

[Low and Behold]

Nice job! How long did this take you?

I'll call it a full day with everything. If I were trying to do it faster I'm sure I could have shaved a few hours, but I always take my time. I drained the coolant and removed some stuff the night before whilst BBQing, soaked the valves that were closed overnight, then cleaned them the next day and did all the other stuff.

Did you get your LPFP changed?

[KillerQuattro]

I did... The car starts without a sputter now! Overall, the car drives so much better, that I'm having to re-learn the power band.. Can definitely feel that its smoother in general, and the power doesn't seem to taper off in the higher RPM's anymore, and even sounds healthier in the high RPM's. Feels almost like I repaired a small boost leak.. Before, when i would be cruising down the highway, mash it to WOT, (I'd get the feeling there wasn't a reserve of fuel waiting for it) it would take a second for everything to catch up, finally resulting in some power. But now, if I mash it on the highway it just pulls and pulls until I let off. Glad this has solved my problem.

And I'm glad that you solved yours! Hopefully you wont need to grab that LPFP for a few more years..

[Low and Behold]

I did... The car starts without a sputter now! Overall, the car drives so much better, that I'm having to re-learn the power band.. Can definitely feel that its smoother in general, and the power doesn't seem to taper off in the higher RPM's anymore, and even sounds healthier in the high RPM's. Feels almost like I repaired a small boost leak.. Before, when i would be cruising down the highway, mash it to WOT, (I'd get the feeling there wasn't a reserve of fuel waiting for it) it would take a second for everything to catch up, finally resulting in some power. But now, if I mash it on the highway it just pulls and pulls until I let off. Glad this has solved my problem.

And I'm glad that you solved yours! Hopefully you wont need to grab that LPFP for a few more years..

Awesome [up]

I logged my LPFP Duty Cycle last night and.... 63.7% (Almost exactly what it was 8 months ago). So it hasn't really gotten worse, but I may change it anyway this summer being as its bound to go bad.

[ShelbyM3]

How's she been behaving after a couple days? Anymore predetonation?


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[Low and Behold]

How's she been behaving after a couple days? Anymore predetonation?

Your mom's been behaving after a couple days [:p]

None yet. Driving it back to Bend next weekend with wife, niece, dog, Thule, skateboard, golf clubs, and a partridge in a pear tree. That will be the ultimate test really - driving through the mountains with a full avant. You never go full avant [>_>]

[Okedokey]

Your mom's been behaving after a couple days [:p]

None yet. Driving it back to Bend next weekend with wife, niece, dog, Thule, skateboard, golf clubs, and a partridge in a pear tree. That will be the ultimate test really - driving through the mountains with a full avant. You never go full avant [>_>]

Rule #22

[Low and Behold]

https://uploads.tapatalk-cdn.com/20170712/92f5338df96ad14b78ad970278080d30.jpg

[Low and Behold]

Good thing I didn't hold my breath... Issue is still present, though not nearly as bad. Basically now when I hear the chattering under load (2-3k rpm) and feel the loss of power + hesitation, its not as loud and no smoke accompanied with it like there used to be. Maybe because I scrubbed the valves...?

Not mad about cleaning the carbon. Needed to be done eventually and was a good thing to learn.

LPFP here we come.

If that doesn't fix it, I'm driving it off a cliff and collecting on insurance... Or just continue to drive strategically.

[Okedokey]

Its a toss up between the LPFP and the controller. I installed the RS4 controller and it dropped the duty by 20%.

[Low and Behold]

Orly... which one is cheaper haha


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[Okedokey]

About the same price mate

[tloft4]

https://uploads.tapatalk-cdn.com/20170712/92f5338df96ad14b78ad970278080d30.jpg

elbows too pointy

[steampunkjunker]

The PCV systems on those does that and a lot of people end up running a catch can. Check out Forge and BHS etc. You might want to get your intake de-carbon service done as the intake values can get seriously gummed up with no fuel rinsing them in Direct Injection. And he don't get hot enough like with exhaust valves. The GIAC 2.0T tunes are really good although I wish that early torque bump was a little more linear. I've been running mine for 90k. Also maybe try the newest Revision factory pcv valve and breather hose. Good luck!


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[steampunkjunker]

Edit! Never mind saw the other posts finally on this phone!!!


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[Low and Behold]

Edit! Never mind saw the other posts finally on this phone!!!


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Lol. I was wondering...

[Low and Behold]

elbows too pointy

Needs "elbows too pointy" reduction surgery.

[icanfixit]

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[Okedokey]

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Quality post ;)

[steampunkjunker]

On my 2007 GTI the 134BAR RS4 fuel rail valve was a nice upgrade and not too expensive. Hard to access without pulling the rail in my platform but possible to do.


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[steampunkjunker]

Oh just spitballing here but you have the newest piston type diverter valve?


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[Low and Behold]

Oh just spitballing here but you have the newest piston type diverter valve?


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GFB DV+

Went from original -> piston -> GFB



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[Low and Behold]

Mini update -

Replaced LPFP this evening. The car still acted up a couple times on my way home after filling up my gas tank. I was a bit discouraged.

Checked duty cycle on the pump when I got home and it was @ 55% so that's good. It was a 63% an hour before I changed it.

Took it out for another spin after that and couldn't replicate the issue. Maybe it had to work out some bad pressure? Not sure if that's a possibility. Either way my fingers are crossed. The hesitation under load has smoothed out considerably. The logged numbers are encouraging but I've learned not to get my hopes up.


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[Okedokey]

Always replace the filter when you replace the pump, a clogged filter can sometimes cause the pump to work hard and burn out. Cannot remember if you've already done this.

[Low and Behold]

I did a while ago, but didn't change it today. I actually have a new one I'll throw in this weekend


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[irish07]

Tried reading through a few pages to see what issues your still having vs what you've replaced.

You still have detonation under load? Medium or only wot load?


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[esandes]

The oil consumption issue has a lot to do with piston rings-bad rings and/or installation, valve and turbo seals.

The EGR and PCV (crank case vent) dump that oil back in the engine instead of the exhaust.

My old engine had oil consumption issues since it was about a year old. It got worse over time then the oil pump crapped out.

Anyway, the rebuilt engine runs like a top and doesn't burn oil. The oil consumption may be causing misfires. Carbon fouling (thanks to DI).

[Low and Behold]

Always replace the filter when you replace the pump, a clogged filter can sometimes cause the pump to work hard and burn out. Cannot remember if you've already done this.

Fuel filter replaced mate. Running strong still

[Low and Behold]

Tried reading through a few pages to see what issues your still having vs what you've replaced.

You still have detonation under load? Medium or only wot load?

Long-ish thread I know so I don't blame you for not reading all of it, but the lpfp fixed it as of my last update.



The oil consumption issue has a lot to do with piston rings-bad rings and/or installation, valve and turbo seals.

The EGR and PCV (crank case vent) dump that oil back in the engine instead of the exhaust.

My old engine had oil consumption issues since it was about a year old. It got worse over time then the oil pump crapped out.

Anyway, the rebuilt engine runs like a top and doesn't burn oil. The oil consumption may be causing misfires. Carbon fouling (thanks to DI).

Again, read the thread haha. Literally everything you've just mentioned has been covered aside from the oil pump. Sorry that happened to you. Theres a very low percentage of cases where the rings are actually bad. Higher percentage chance that the turbo seals go bad first... And in many/most cases it seems to be PCV/VC related which is great because its a much cheaper fix.

And this is just what happened to you - not a rule of thumb for what usually happens. Tons of us on here can attest the fact that replacing our VC fixed our oil consumption issues. Sure fixed mine. And now the LPFP fixed the apparent fueling issue. Wonder whats gonna go wrong next [rolleyes]

[klrider44]

I have what seems like a similar issue. Feels like a fuel issue to me. I have a JHM upgraded lpfp going in soon, so I shall see. It's just frustrating cause I have replaced my lpfp twice. I am JHM stage 3 but the kit is made to run with the OEM lpfp.


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[Low and Behold]

Im back [headbang]

Now let me start by saying that I never did resolve this issue. It's been a couple of years, and Ive mostly been driving the car in a way that avoids this issue from happening. Was going to start a new thread, but figured I could keep the saga going here.

With two more years of knowledge under my belt (brings me to about 13 years now), the title of this thread going forward should really be "Help: sputtering/clicking under medium load". Specifically in the 2-3k RPM range. I can't say for sure its detonation or preignition, but its metallic clacking noise coming from under the hood.

RECAP:
When accelerating, ether from a dead stop or while cruising on the freeway, if I give it a decent amount of gas I get a loss of power/clicking/bit of smoke while building boost. Once I get above 3-3.5k is goes away. But the sound can be very unnerving, and I know something definitely isn't right. Wont happen in 1st gear, rarely happens in 2nd and 3rd. Its more in the 4/5/6 range.

With my first child due in about 7 weeks, I'd sure like to get this situation figured out once and for all.

A few things have changed since I originally started this thread, the most important being that I now own VCDS - so I'll need some expert insight on what to log.

PARTS CHANGED (in no particular order):
Plugs / coils
Turbo (used) / N75 / DV
Valve cover and PCV (fixed oil consumption)
Carbon Cleaning performed, injectors cleaned
MAF
Intake Cam / HPFP / Follower replaced by Audi
Note: This was not due to a broken follower, but I fabricated one to get Audi to change it under warranty so I could rule this out. Long story.
LPFP

THEORIES:
A bad injector, or two?
Knock sensors - this is a shot in the dark. Wondering if the timing isn’t being adjusted due to a bad sensor. No codes are being thrown.

I know this a long thread, so hopefully the recap will suffice. Ive seen similar threads to this from a while ago but they never had an outcome.

Looking for any advice. Theres some new, knowledgeable faces in here that I'm sure can provide some insight. Tell me what to log. Tell me you need me to post scans. Tell me I'm an idiot. Whatever helps at this point!

I appreciate you all!

135457

[EvolutionArmory]

Log block 003, 004 and 020 from 1500-redline

003 will give you throttle position and timing

004 will give you coolant and intake temps

020 will give you individual timing correction for each cylinder.

Log all 3 at the same time in turbo mode. Don’t use advanced. Make sure the pedal is to the floor for the whole log.

[Low and Behold]

Log block 003, 004 and 020 from 1500-redline

003 will give you throttle position and timing

004 will give you coolant and intake temps

020 will give you individual timing correction for each cylinder.

Log all 3 at the same time in turbo mode. Don’t use advanced. Make sure the pedal is to the floor for the whole log.

Thats what I'm talkin' about! Thank you - will do this as soon as I can.

[Jay-Bee]

Thats what I'm talkin' about! Thank you - will do this as soon as I can.

Upload the logs to MaloneTuning Log viewer, it indexes and graphs it all out for you nicely too, you can mouse over for time stamps through the whole logs and you can share the link or screen shot it.

https://log.malonetuning.com/upload

[CleverA4Name]

You’re an idiot.

But excited to log these and see if they help!


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[Low and Behold]

You’re so good looking.

But excited to log these and see if they help!


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Fixed. Thanks Trent!

[EvolutionArmory]

You don’t have to use an outside source to make graphs. You can do it easy enough with Excell or Google sheets

[Low and Behold]

Here are a couple logs. Im super happy I was able to capture the sputtering, since sometimes it doesn't want to reveal itself.

1500 to Redline (almost) (https://log.malonetuning.com/chart/263682#H8KLCABDw7tMXQIDbcKOw40OwoIwEMKEw59lw4%2FCu wkVw7x7FsOCYcK1KzRBSsOawq1Bwp9eCsORwpjDoHFmwr7CmUx dw4PDlcOfL24QasKDT2MELBrDjGbDr8KDe8OJLBFaGSTCsArCr MOJw7DCkMKgwqTCnibDosOJw6XDhsOaw6nCnBXCssKsHEXCs1n CosKGJDlha8Opw7nChSHCuMK2w5NlbCZ%2FwoLCukDCgzvCrHD Cjwc8w6IJw49ow6ZlMAvDi0l9HHvCt2zCm2pbLz%2FDpMOGXgU Vw7DDv8Omwo3DuyhNw7MGwo3DjMK6LAwBAAA%3D)

Sputtering/Clicking (https://log.malonetuning.com/chart/263685#H8KLCADCi8O9TF0CA23CjcONDsOCIBDChMOfwoXDs8K QFMKtf8OPw5LDtMKww4pKScKwNMKwwpjDqsOTW8Oaw4R4w7DCu DPDn3zDm3XDqhYfVz%2FCsnYpwpYpKzQ9ahhiw7JvXk4ow4cjJ xJWWzM%2BOcKJwpbCqGdNwrPCr8KLbTN4w4vDmsKSUGbCqcOhH sKSCsOXwobCrMOVwq8vwqzCknfCg8KswrLChcO8KcK6BgY7wrQ 4w6DCiBPDjsK4w4AsZmVWwpbCisOEPAXCv8K6TcO7w7%2FDo8K dQsOmwr7DvwDCqcO5KzjDlwAAAA%3D%3D)

For the sputtering - about 2600 RPM is when things go to shit. MAF, Throttle Angle, and Timing retardation only in Cyl 4.

TIA

[az]

[EvolutionArmory]

So you only have correction factor for cylinder 4? If yes you should do a compression and leak down test and see if there is trouble with that cylinder. If compression is dramatically lower than the other 3 you have a piston or cylinder issue. If it’s not, something else is causing it. Maybe head related, maybe fuel delivery. Maybe a bad knock sensor too but that would probably show up on cylinder 3 as well since they both share a knock sensor. It could be false knock from a bad sensor or it could be legit but at least you know that it appears to be generated from cylinder 4.

It might be a good idea to log the misfire counter too.

And I hate the Malone site logs. It makes them a huge mess to read when you upload multiple groups. 😞

[Low and Behold]

Thank you. Compression is ~175 across the board. Have not performed leakdown.

I’m wondering why the throttle angle and MAF take such a huge dip. Could it be the throttle body? That would affect all cylinders though...

Sorry about the Malone shit. Just seemed like an easier way to upload it.


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[Jay-Bee]

And I hate the Malone site logs. It makes them a huge mess to read when you upload multiple groups. 😞

If you're used to excel stick with it, but we have a TDI ECU tuning FB group and use it tons. It's drag and drop easy peasy for people new to logging.

You can click on the items above the graph and turn lines on and off to clean it up too.

[Low and Behold]

If you're used to excel stick with it, but we have a TDI ECU tuning FB group and use it tons. It's drag and drop easy peasy for people new to logging.

You can click on the items above the graph and turn lines on and off to clean it up too.

I was pretty impressed with being able to load the sheets into Malone. Definitely made it easier for me to understand.

[Low and Behold]

So you only have correction factor for cylinder 4? If yes you should do a compression and leak down test and see if there is trouble with that cylinder. If compression is dramatically lower than the other 3 you have a piston or cylinder issue. If it’s not, something else is causing it. Maybe head related, maybe fuel delivery. Maybe a bad knock sensor too but that would probably show up on cylinder 3 as well since they both share a knock sensor. It could be false knock from a bad sensor or it could be legit but at least you know that it appears to be generated from cylinder 4.

It might be a good idea to log the misfire counter too.

And I hate the Malone site logs. It makes them a huge mess to read when you upload multiple groups. [emoji20]

Clarifying question - is it weird that there is ZERO retardation on cyl 1 - 3? I assumed I would see varying degrees of it across ALL cylinders, however we see here it’s only on 4.

[EvolutionArmory]

It’s not unusual to see no correction factor, no. Ideally that’s what you want.

Well you know that your issue is cylinder 4 related. Do a leak down test and see if that cylinder is worse than the others.

If the leak down test is good I’d probably pull the intake, replace the knock sensor, carbon clean the valves and replace that injector while you’re in there.




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[Low and Behold]

It’s not unusual to see no correction factor, no. Ideally that’s what you want.

Well you know that your issue is cylinder 4 related. Do a leak down test and see if that cylinder is worse than the others.

If the leak down test is good I’d probably pull the intake, replace the knock sensor, carbon clean the valves and replace that injector while you’re in there.




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Will do leak down test and report back.

In the meantime, still wondering what would cause the MAF and Throttle Angle to nosedive like that while the RPMs are still going up.

If anyone has thoughts I’m all ears

[Charles.waite]

Bad ground?

[aluthman]

Maf is probably just reacting to the change in throttle angle. The throttle angle could potentially be a tb issue or even the ecu trying to pull back due to detected knock in cyl 4.