broken rocker arm/lifter White smoke from exhaust and strong smell of diesel

[Tommy5150]

Hey guy's,

Decided to do some digging around and resolve some issues with my 2005 A4 B7 Avant 2.5 TDI.

Main issue: Issue started @ roughly 1500 rpm only, under slight acceleration/idle. Accelerates great doesn't loose power starts great everytime does matter hot or cold. I discovered it when I started up the car, had it in park and slowly started accelerating up to around 1500 rpm. What happens is as soon as it got to that point started spluttering a bit kinda like chocking. As soon as I accelerated harder was fine. It was just at the 1500 mark. Same as when I drove and got to that point it any gear started hesitating. But like I said as soon as I accelerated took of fine without a problem. Up to the 1500 mark fine and above that fine, does not miss a beat very smooth.

So started digging around and at first thought it might be an injector issue. (Injectors in this car are mechanical with only one out of the 6 having a wire coming out of it.) So decided to pull the right hand side (passenger) rocker cover off and get the injectors out. As soon as I got the cover off I saw the #3 exhaust rocker arm off wedged in the side of the engine block, with the hydrolic lifter/tappet broken above it with the bottom half of it still in the hole (see pic). Pulled it all out with a magnet and checked the exhaust cam for damage and it seemed to be fine. All other lifters and rocker arms where good and in place as they should be. So seeing as though I had to change the one decided to do them all, all lifters and all rockers. Put everything together and thought sweet. Timing marks spot on. While I had the injectors out decided to pull them apart clean them up, soak the tips over night in Carb cleaner and blew them out with air compressor.

IMG-9788(1).jpg

Turned engine on, seemed to run a lot better was not chocking or cutting out as much as before, was a lot smoother, but still not right. There was still slight hesitation around the 1500rpm, and this time a lot of white smoke after a bit. So it seems to me there is still an issue, with burning the diesel in the cylinder itself. I'm thinking because I couldn't see the valve on the rocker arm & lifter that was slipped off/broken, I'm thinking there could possibly be an issue there inside the head with the valve/s. Tomorrow I am borrowing a diesel compression tester to test each cylinder and make sure I am getting correct compression in every cylinder. That way I'll know for sure if there is any damaged valves under the head.

This is the first time I'm working on a diesel engine, seems was more complex with tubes and pipes and cables running everywhere compared to the petrol/gas engine.

Has this happened to anyone or can you give me an idea of what could be going on inside and causing this? (hesitation/chocking at 1500rpm and white smoke) and bad diesel smell. The smoke seems to stop after 1500 rpm and same as before 1500rpm.

What would cause a car to push white smoke out or exhaust or un-burnt fuel? Maybe some of you might have an idea or have heard of something similar happening before.

Much appreciated for any help.

[Theiceman]

There are not many here who have diesel a4s. maybe audiworld would be a better place. but generally speaking Audi head gaskets are solid and white smoke is usually unburned fuel..

Sent from my SM-G973W using Audizine Forum mobile app

[Tommy5150]

There are not many here who have diesel a4s. maybe audiworld would be a better place. but generally speaking Audi head gaskets are solid and white smoke is usually unburned fuel..

Sent from my SM-G973W using Audizine Forum mobile app

Hey, cool thanks heaps for you reply. Will check the compression now to make sure it is as it should be and that there isn't a bad valve or something causing a compression leak stopping each cylinder properly igniting the fuel.

Thanks again mate, cheers

[PhireSideZA]

White smoke out of a diesel engine can indicate overfuelling, which would be very bad - I know it is a chore but I would do the compression test and also have your injectors tested. If you have an injector that is stuck open or not working properly it will melt a hole in your cylinder and ruin your engine in no time at all (not to mention fuel washing past your rings and diluting the oil in your crankcase).

[CrickiKaze]

Sounds like you may have a bent valve, compression test should reveal lower compression for that cylinder. Fuel leaking out due to lack of sealing and not providing proper combustion. I'm only semi familiar with the CJAA in my wife's Jetta (got it late last year) so figuring it out so take that with a grain of salt. Worked on other diesels but outside of fueling/ignition its all the same IMO, comparatively speaking, so don't let that be a hindrance to your though process.

[Tommy5150]

White smoke out of a diesel engine can indicate overfuelling, which would be very bad - I know it is a chore but I would do the compression test and also have your injectors tested. If you have an injector that is stuck open or not working properly it will melt a hole in your cylinder and ruin your engine in no time at all (not to mention fuel washing past your rings and diluting the oil in your crankcase).

Hey, Tested the injectors with VCDS and they all seemed fine, didn't get any reading out of the norm. Tested them on idle and on 1500rpm when it starts chocking a bit. Was supposed to test the compression today but my adapter did not fit into the glow plug whole. So getting another one hopefully tomorrow. Once I do the compression test i'll know more but taking that as my starting point. Once I know compression is good I can move on from there to state of cams, pull out injectors and table test them, and diesel pump pre injectors. But yeah I can imagine not good if injectors leaking....

Also pulled and cleaned injector tips overnight in carb cleaner and blew out the next day with air compressor and tested they seemed fine misting nicely...

[Tommy5150]

Sounds like you may have a bent valve, compression test should reveal lower compression for that cylinder. Fuel leaking out due to lack of sealing and not providing proper combustion. I'm only semi familiar with the CJAA in my wife's Jetta (got it late last year) so figuring it out so take that with a grain of salt. Worked on other diesels but outside of fueling/ignition its all the same IMO, comparatively speaking, so don't let that be a hindrance to your though process.

Hey, Yeah I'm thinking that too that a valve might be bent only slightly and causing this whole issue. Went to test the compression today but the kit I had did not have a glow plug adapted that fit. It did have one that had the right thread but was too short. So looking at getting a longer one hopefully tomorrow. Kinda hoping it's the valve as would be a pretty easy fix for me rather that having to search further. But yeah we'll see. I'll post back once I do the compression test.

[Tommy5150]

Checked the compression today... Issue I'm having is that I'm getting 10 - 12 Bar on each cylinder. How is that even possible? The car starts straight away hot or cold and idles smoothly does not back fire neither does the engine shake. How if I'm supposed to have min 27 bar and I got 10 how is my car running so smoothly? I thought that if it was that bad it would start hard and run like crap no??

Baffled...

Can anyone give me some input on this??

[CrickiKaze]

All your other valves are bent, the head gasket is blown, timing jumped, valve springs are weak, massive carbon/soot build up on the valve ....could be a couple of things. Got a bore scope to look in the cylinders?

You may have to just pull the head.

[CrickiKaze]

Put some oil in the cylinders and retest, that will negate some air getting past rings.

[Tommy5150]

Hey guy's,

Can any one here help me understand my injector quality?

I ran VCDS MB13 Idle Stabilization (Injection Quality Deviation) an got:

This is @1500rpm ( where I have a slight problem with choking and white smoke strong diesel smell)
Cyl 3 - +1.88mg/str
Cyl 1 - +1.73mg/str
Cyl 6 - -0.39mg/str
Cyl 4 - 0.00mg/str
Cyl 5 - -0.31mg/str

@ Idle
Cyl 3 - +1.65mg/str
Cyl 1 - +1.41mg/str
Cyl 6 - -0.24mg/str
Cyl 4 - -0.16mg/str
Cyl 5 - -0.31mg/str

VCDS states these measurements have to be between +1.5 and - 1.5. So going off this does this mean Cyl 3 & 1 have gone bad? As under idle @1500rpm where the issue is they are over +1.5. Is that right?

Why is there no Cyl 2? Is that cause that's the one all these measurements are off I mean compared to? or is cylinder 2 totally gone not even registering? Because some said that as long as they are between 3.5 +/- they are fine. Just confused me as VCDS states within 1.5 +/-.

I know these injectors are mechanical with no wire apart from 1.

I hope someone can help me understand and clear this up.

I have included a video of the full testing going through the measuring banks starting at 1. But please fast forward to measuring bank 13 & 14. First it is just at idle then both @ 1500rpm.

https://youtu.be/6WTku9kErEU

If you watch more of the vid please let me know if you notice anything else that's wrong in the other measuring banks.

Thank you very much appreciate any help.
Cheers

[CrickiKaze]

There is a section in VCDS that has inputs for injector info/serial numbers, at least for the CJAA, not sure exactly where but you should see in there is an info for each location.

[Tommy5150]

Ok so I've kinda worked out whats going on. The gauge was good as after testing with a known good one I still got exactly 10 bar per cylinder bang on. Seeing as though the car starts and drive well I am only left to believe that's as it should be. I've always had a big discrepancy in cylinders when there was something wrong. Each cylinder is the same so I feel they are good.

So from this looks like cylinder 1 & 3 are bad, and with this I'll also change 2. Apparently this model does not show 2 but seeing as tho it's next to 1 & 3 in the same head I'll prob change it too.

What I did try today is run a Liqui Moly diesel purge (1 liter) through the engine, was hoping it would clear those bad injectors out. But it didn't. The liquid that was left in the bottle at the end too was pretty clean I would say.
What was strange but was when running the moly I did not get any hesitation or chocking at all @1500rpm as was my main issue, neither did I get any smoke at all. Ran so smooth. I really thought it had cleaned the injectors out and fixed the chocking @ 1500rpm issue but it did not. As soon as I went through the bottle of moly and plugged the Diesel fuel filter up was back to normal. Hesitation and chocking exactly at 1500rpm, and white smoke (strong smell of unburnt fuel).

Does anyone know why this is? Does it just run better with Diesel Purge being a higher strength fuel or something? I want to try pouring diesel into the bottle and hooking it up as I did with the Liqui Moly and see what happens as a test. To see if it gets rid of the Hesitation/Choking/smoke @1500rpm. Was thinking if so them maybe my issue is between the fuel tank in the back and my diesel filter in the engine compartment. Just trying to think how I could problem solve and narrow down the issue.

Thoughts?

I feel it cant be all my valves are bent (and to have the exact same compression on each cylinder? Don't think so), the head gasket is blown (no water missing in coolant system at all), timing jumped (checked timing spot on), valve springs are weak (again I doubt they are all weak exactly the same, readings would be off cylinder to cylinder only if slightly), massive carbon/soot build up on the valve (again I doubt that it would be exactly the same in each cylinder) and on top of that car start and runs perfect.

[CrickiKaze]

Check your timing. You should be able to see something in VCDS.

[Theiceman]

I suggest a VW forum that might have this engine.. you might get some good help.

Sent from my SM-G973W using Audizine Forum mobile app

[Tommy5150]

Hey guys,

Problem solved!

Believe it or not but was a super easy fix after I found it.

Had no error code at all but yesterday engine mark popped up so scanned it. Got 00560 - exhaust gas recirculation system 08- 10 0 control limit surpassed - intermittent.

So started look at the whole egr system and found that the erg solenoid was not working but stuck on open so engine had a constant air leak. Changed solenoid with new one problem solved! Car runs great loads more power, no smoke or strong diesel smell at all and does not backfire nor is there any more hesitation at all revs smooth and great! Injectors now run as they should no high values all around 0.3.

Thanks heaps for everyone's help. Funny how such a easy fix nearly had me pulling the engine and head apart.

Hopefully this thread helps other people with this or a similar problem.

Cheers

[PhireSideZA]

Hey guys,

Problem solved!

Believe it or not but was a super easy fix after I found it.

Had no error code at all but yesterday engine mark popped up so scanned it. Got 00560 - exhaust gas recirculation system 08- 10 0 control limit surpassed - intermittent.

So started look at the whole egr system and found that the erg solenoid was not working but stuck on open so engine had a constant air leak. Changed solenoid with new one problem solved! Car runs great loads more power, no smoke or strong diesel smell at all and does not backfire nor is there any more hesitation at all revs smooth and great! Injectors now run as they should no high values all around 0.3.

Thanks heaps for everyone's help. Funny how such a easy fix nearly had me pulling the engine and head apart.

Hopefully this thread helps other people with this or a similar problem.

Cheers

Brilliant! Very glad to hear the fix was a cheap, easy and quick one!

[CrickiKaze]

I didn't think to look into any pending codes, found and fix is all that matters.

[Tommy5150]

Brilliant! Very glad to hear the fix was a cheap, easy and quick one!

Was over the moon.

[Tommy5150]

I didn't think to look into any pending codes, found and fix is all that matters.

The funny thing was I check fault codes so many times and there was nothing there about the egr, there was no fault codes at all until 2 days ago when the engine light came on. I wish it would of gave me this fault code straight away as it would of saved me sooo much time. But I guess that's all part of it. Main this is I learned allot through this process as it was my first diesel engine that I worked on and now have a good understanding of it. So when I next come across another diesel I will be better prepared. Also I now know that if this happens again with no fault codes to check compression then air intake/egr.

Exactly found and fix

[Jayz691]

Awesome to hear man!
So i guess its really was leaking comp, and those readings were accurate. I know nothing about TDI's, so never would have thought too look there. But now, will rem this.. Congrats!

Sent from my LM-V600 using Audizine Forum mobile app

[Tommy5150]

Awesome to hear man!
So i guess its really was leaking comp, and those readings were accurate. I know nothing about TDI's, so never would have thought too look there. But now, will rem this.. Congrats!

Sent from my LM-V600 using Audizine Forum mobile app

Thanks man! Yeah had a huge air leak and ecu was trying to correct this by pumping more diesel into injectors(engine) which in turn did nothing but choke it, spitting unburnt fuel out into exhaust. Was a terrible smell. And thats why my injector readings where through the roof. Yeah same. This lesson will be with me forever!

Thanks