2.0t timing mess

[Thompson]

Hello guys, I'm new here and need a little help for a diagnosis.

Lately I was planning to do a timing belt job on my recently acquired a4 b7 2.0 tfsi only to find out after a quick check that the cam follower was completely destroyed. So an intake cam - follower - hpfp replacement was needed too. So I did all of these and while I was at it, I put a new chain and tensioner. I have to mention that the car was running well, no misfire and had no codes before.

For the job itself, I used the alignment tool and counted the links (followed the 18-19 links rule) for the chain job, because I know it's the best way to be accurate. For the timing belt, the timing marks all lined up after a couple of manual rotations of the engine. I even counted teeth on the belt between marks I had made just to be sure to transpose the new belt at the same place as the old one. Everything else I did according to Bentley, Elsawin and some other online resources like DIY's here and youtube like Astral Auto repairs channel (thanks everyone).

When I first started the car after (cold start), it ran fine for about 30 seconds to 1 minutes at approx 1100 rpm, then the rpms dropped to 800-900 and the car started misfiring. So I thought this is weird. I revved it to 1100 again, then 1500, then 2000 and engine feels smooth, no misfires. I went back to check, timing is according to specs : timing belt, all marks still lined up, tensioner is set the right way; timing chain, the right number of links is spot on, tensioner does his job and the 3 o-rings for the adjuster are in good condition (I had replaced these). When the engine is warmer, misfire starts right as the engine starts because the engine doesn't have the small period where it sits at 1100-1200 rpm on a cold start, but it rather instantly picks its idle at 800-900 rpm.

I have a basic scan tool, but no VCDS, and codes are :
P0016 : Crank/Cam Position Correlation
P0300, P0301, P0302, P0304 : misfire, random and cylinders
P0171, P0174 : System too lean
P0000 : ?

So I switched spark plugs, and it changed nothing (not surprising), same for coils. I changed camshaft position sensor and nothing too. I visually checked for vacuum leaks, doesn't seem to be the cause. All PCV lines are well connected.

Anyone have any ideas why it is misfiring at idle, but not with increasing rpm ? I don't understand what could cause this besides the timing if the timing is visually to spec...
Also, any input would be appreciated

Thanks
Thompson

[Appa]

When the cam follower was destroyed. Did you make sure there wasn't any metal inside your motor? It could also be a bad PCV valve. My old b7 a4 had similar issues and that was the culprit.

[Thompson]

Thanks for your reply,
The cam follower, I don't know when exactly it broke, but I managed to gather a lot of the metal parts that where still lodged in the cam adjuster cover, especially behind the tensioner where it attaches to the head of the engine. The screen on the cam adjuster cover was still intact, I also changed the oil and it didn't appear to be metallic.

Thanks for the tip on the PCV valve, because it was working before the job, I didn't think to go look at that, I will take a look. Did yours failed in similar circumstances ?

Thompson

[Appa]

Nice!! Sounds like you got it all cleaned out. My PCV valve failure was random around 100k miles. Easy way to check the PCV is to have the engine running and try to pull off the oil cap. If you can pull it off then its good but if you cant then its bad I believe.

[Thompson]

Thanks Appa ! Ok so PCV doesn’t seem to be the issue, I could pull the oil cap, and there wasn’t any suction. At least now that seems ruled out. Thanks for the tip.
Also the vibration seems to be very rythmic. Almost like it misses by cycle, but a lot slower than the engine speed itself. I don’t know if I’m clear. When I had misfires due to vacuum leaks and also bad coils with some of my past cars, the misfire was more random and the car would sometimes stall when at idle. Now in this case the engine doesn’t want to stall but it does vibrate a lot more and in a cyclic manner. Don’t know what that could tell. This, along with the timing job really makes me worry that something went bad with the timing, but I can’t tell what..

[Theiceman]

The giveaway is p0016.
The car is over advanced for timing..that's why it runs good at higher rpms.. because at higher rpms it runs at advanced timing so it's fine

P0016 is telling you cam and crank don't agree I'd start there.
Did you clear all.codes after you finished the work and this is new ?
The misefire codes are a symptom. Ignore them. Fix the p0016


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[Theiceman]

I don't know what 18/19 is but if it's not set up like this pic it's wrong.. the white dot emulates the dot on the intake cam.
Count over the top. Not underneath.
Hopefully you painted your chain like I did and the intake cam tooth.



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[Brillo]

Thanks Appa ! Ok so PCV doesn’t seem to be the issue, I could pull the oil cap, and there wasn’t any suction. At least now that seems ruled out. Thanks for the tip.
Also the vibration seems to be very rythmic. Almost like it misses by cycle, but a lot slower than the engine speed itself. I don’t know if I’m clear. When I had misfires due to vacuum leaks and also bad coils with some of my past cars, the misfire was more random and the car would sometimes stall when at idle. Now in this case the engine doesn’t want to stall but it does vibrate a lot more and in a cyclic manner. Don’t know what that could tell. This, along with the timing job really makes me worry that something went bad with the timing, but I can’t tell what..

Contrary to other opinions I doubt the PVC valve is causing your codes. Agree with Theiceman, fix the p0016 first.

Regarding the PCV system, at idle rpm there should be some suction pulling the oil fill cap down, and when you remove it you should immediately get a rough engine idle because you just createed a massive air leak directly into the IM. If you don't get some suction and rough idle your PCV valve might not be functioning correctly. If you place your palm over the oil fill and you feel positive pressure, your PCV valve is definitely not functioning properly. Replace it only with an OEM part appropriate for your VIN (there are two different versions based on the VIN). Also, make sure the tubes going from the oil filter housing to the rear port of the PCV valve and the other one going from the PCV valve to the IM do not have any leaks in them. They can get brittle with age and develop cracks.

[Theiceman]

Agree with above 1.8 and 2.0 are completely different with PCV.
1.8 is neutral
2.0 should be trying to suck your palm in.

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[Jayz691]

If you counted links like they show in the astral auto video, the chain is prob fine. But like mentioned, I would double check the timing belt and make sure its not a tooth off. And as mentioned, for pcv you should have some suction, but not a ton. When mine was bad I could barely pull the cap off when running. Had a small tear in the diaphram. You can physically check the pcv too. One valve you can check by trying to blow into the port that goes to IM. And pull the round cover off to check the diaphram, only way you can check it. Only take a little leak to give a rough idle. This little cut made mine run rough.1126191336.jpeg

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[Theiceman]

Actually you can put your finger over the exhaust hole in the side of the cap. If idle smoothes out your diaphragm is torn.

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[Thompson]

Thanks for the inputs everyone ! I agree with all of you, the p0016 tells me that it's timing related so it's the thing to keep in mind. I'll take notes though for the PCV.
Thanks for the pic Theiceman. This is exactly the way I did it and when I go back to see, it's still on the right spot. Strange, because I would have thought the advanced timing could have been a good explanation to my problem. I'll go back to check the belt and see if I can take pics.
One thing I forgot to mention that I wasn't sure when doing the chain job though is that the alignment tool didn't fit in the cam slots when engine was at TDC, it only fitted a couple of degrees before the timing belt TDC mark was reach on the plastic cover. But this was the same before and after the timing belt replacement, and because I did the belt job after, this means that it is probably normal... I'll try to see if I have some pics

[Theiceman]

Remember also that with the timing.Cover you also have the oil phaser rings . cam.phaser. n205. They all affect cam timing.. you obviously got the pin in the exhaust cam. Only other thing maybe ground on timing cover.
If your static timing checks out. The only thing left is dynamic timing ( mehanical cam advance ) if your sensor signals are being picked up by ecu..

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[Jayz691]

Actually you can put your finger over the exhaust hole in the side of the cap. If idle smoothes out your diaphragm is torn.

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Really? Did not knoe that. I just always popped the top off, then theres no guessing. But good ta know.

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[ultima]

Check your DV. My car was misfiring, idling roughly, giving timing codes, and driving smooth at higher RPM's and that was caused by my seized diverter valve. Worth a check

[Mister J]

I haven't done this job yet myself but am planning to. I saw this linked in another thread and saved the video. The cam locking tool isn't as accurate as you think and this video points it out. Have a look as it might help you. He points it out at around 12:45 but I recommend you watch the whole video.

https://youtu.be/ZnZz4LgqoBo

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[Thompson]

Remember also that with the timing.Cover you also have the oil phaser rings . cam.phaser. n205. They all affect cam timing.. you obviously got the pin in the exhaust cam. Only other thing maybe ground on timing cover.
If your static timing checks out. The only thing left is dynamic timing ( mehanical cam advance ) if your sensor signals are being picked up by ecu..

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Yeah Theiceman thanks for the input, seems to be pointing to dynamic timing. I'm going to check the N205 valve later this week, visually and check resistance, some guys say it should read between 10-18 ohms, do you guys have experience with that, never tested these before. I'm going to look at some DIY.
I'm thinking it might be a lack of oil pressure reaching to the adjuster at low rpm, that might affect doing its job of timing adjustment ? Hopefully the adjuster itself is good, this part is quite expensive.

Thanks for the input also Ultima, definitely worth checking the DV. Your symptoms are really similar to what I have

[Thompson]

I haven't done this job yet myself but am planning to. I saw this linked in another thread and saved the video. The cam locking tool isn't as accurate as you think and this video points it out. Have a look as it might help you. He points it out at around 12:45 but I recommend you watch the whole video.

https://youtu.be/ZnZz4LgqoBo

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Thank you ! I'll have a look at it

[Theiceman]

im pretty sure at idle it is full retard, there is no advance. the phaser is not supposed to move into advance. I had a problem recently on a B8 that was misfiring at idle. a valve had failed ( different set up completely ) oil was leaking past it causing the phaser ( timing) to advance giving timing codes and misfires.

worse case i would take that phaser apart and inspect it.

[Theiceman]

Check your DV. My car was misfiring, idling roughly, giving timing codes, and driving smooth at higher RPM's and that was caused by my seized diverter valve. Worth a check

do you have a theory as to why diverter valve affects cam timing ? i've never heard this as a route cause before. what codes were you getting ?

[Cyrik]

do you have a theory as to why diverter valve affects cam timing ? i've never heard this as a route cause before. what codes were you getting ?

I'm curious too actually. Maybe because there's too much pressure from boost not being able to vent or something....?

Most I've ever gotten was a turbo underboost code from a DV and that was because it was stuck open before I replaced it. Basically made a big boost leak.

[Theiceman]

I haven't done this job yet myself but am planning to. I saw this linked in another thread and saved the video. The cam locking tool isn't as accurate as you think and this video points it out. Have a look as it might help you. He points it out at around 12:45 but I recommend you watch the whole video.

https://youtu.be/ZnZz4LgqoBo

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that's our French Canadian friend .... that is actually a great set of videos he has..
no one should use the locking tool to set your timing , that is what gets you into trouble. counting links is the only correct method.

[ultima]

do you have a theory as to why diverter valve affects cam timing ? i've never heard this as a route cause before. what codes were you getting ?

I have no idea why it caused timing codes, I believe it was stuck extended. I don't remember exactly the codes but some I do remember were Cyl. 1,3? Misfire, Random Cylinder Misfire, and a timing code I don't recall.

[mc_hotmail]

The giveaway is p0016.

I think Theiceman is correct. When I had PCV problems, I had seen other codes you have but never P0016.

However, a bad PCV also has the symptom of smooth idle while cold and in high rpm, followed by rough idle in low rpm. You can temporarily delete the PCV just to rule it out definitively.

[Thompson]

Hello guys,

Just a quick update in case this could help someone in the future. The code p0016 was finally solved by a new camshaft position sensor. However, the symptoms (misfire at idle only and smooth above 1000-1200 rpm) were still there and code p119A - fuel pressure sensor came up. Those symptoms were resolved by replacing the PCV valve. The p119A was probably caused by the major vacuum leak I had at the oil separator.

What i found difficult was that due to the timing operation, i was frozen in the idea that the misfires, p0016 and timing were only one problem.

Thanks for the help everyone

[Jeevan]

Hello guys,

Just a quick update in case this could help someone in the future. The code p0016 was finally solved by a new camshaft position sensor. However, the symptoms (misfire at idle only and smooth above 1000-1200 rpm) were still there and code p119A - fuel pressure sensor came up. Those symptoms were resolved by replacing the PCV valve. The p119A was probably caused by the major vacuum leak I had at the oil separator.

What i found difficult was that due to the timing operation, i was frozen in the idea that the misfires, p0016 and timing were only one problem.

Thanks for the help everyone

did you you see camposition sensor clogged with dirt around it?

[ifloppedtrips]

Just had the same scenario resolved by replacing the camshaft position sensor. It had a ring of gunk around. It was cheap enough to just replace it for peace of mind rather than cleaning it.


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[Jeevan]

Just had the same scenario resolved by replacing the camshaft position sensor. It had a ring of gunk around. It was cheap enough to just replace it for peace of mind rather than cleaning it.


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Asked out of curiosity, It seems like a design flaw with the housing in which cam position sensor lives. The oil near the cam sensor has no way to escape and ends up clogging the magnetic part of sensor. I had dirty sensor which threw P0016 even though my car had meticulous oil change history with top quality oils. Cleaned the gunk and put it back as it happen on the freeway. It was year ago BTW. Its best if you keep that sensor as a backup.

[Thompson]

Yes, exactly, mine had gunk/dirt on the magnetic part !