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Old 13th August 2016, 10:50 PM
snapdragon snapdragon is offline
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Default EGR Cooler Problem

I have had EGR insufficient flow errors for over a year and they have got a bit more frequent. I thought I'd begin giving it a clean today and it is a pig of a job.
It has done nearly 250,000miles and so I expected it to be blocked with coke/soot.
I was using this as a guide:
http://www.vwaudiforum.co.uk/forum/s...GR-Valve/page3

I removed the upper manifold and throttle.
The throttle was a bit dirty but much cleaner than I expected
I then removed both lower manifolds (mainly to access two bolts, otherwise just the left side would do) Many items need to be removed to get to all the bolts and even then it is difficult and requires an assortment of bits.
The lower manifolds were also cleaner than I expected and then I saw from labels on them they were replaced along with the flap motors in late 2010 just before I bought the car. = Thanks to previous owner.

I removed the EGR vacuum mechanism which uses XZN socket - thankfully had a set from removing the seat to do bluetooth. Upon removing the EGR mechanism from the EGR cooler flap mechanism, I found a loose plate inside about 25mm diameter. It was just laid there and was fretted around the edge and had obviously been bouncing around. I checked all 6 intake runner flaps were intact which they were and then realised it is the EGR cooler bypass flap and it had come off the shaft and would move around and sometimes block EGR flow. It is not obvious how it was fastened to the shaft, but there are no corresponding screw-holes on the shaft for the holes in the plate, so I think it was spot-welded. I also found the shaft rather sloppy in it's bushings and this must have contributed to the flap breaking off.

So not what I expected but a new cooler bypass mechanism 059131063D (20 on diagram) is on it's way and I will strip down more on Sunday and hopefully clean and see what gaskets and screws need replacing.

Last edited by snapdragon; 23rd April 2020 at 09:19 AM.
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Old 14th August 2016, 06:46 PM
snapdragon snapdragon is offline
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Gosh 2 days of struggle to get this EGR off.

This was a big help, page 1 & 11 (photos and description) & my question at page 12.
http://www.audi-sport.net/xf/threads...1/#post2118561

I had to cut a small hose on the right of the EGR and then it should just pull off but it 'plugs' into the engine block with two metal union coolant pipes with o-rings on and these corrode to the block and get fouled with what I assume is silicate from the coolant. It took a crowbar and some rubber padding against the right cyclinder head intake face to pop it out.

Now I have it in the house and await the new part (I ordered a J suffix and have a D - and since found that is for the CABA engines not ASB, so hoping it fits - looks identical on the photos.

All the VAG EKTAmparts diagram websites seem to have gone offline which has made it harder.

I have uploaded a video that shows how much slop there is in the mechanism - the top bearing/bushing seems missing and light can even shine through and smoke has clearly been coming out as everything is black and smells of exhaust fumes. Maybe worth checking for this excessive play and soot in situ if you have this engine.

Why are all my photos upside down?

Last edited by snapdragon; 23rd April 2020 at 09:19 AM.
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Old 20th August 2016, 06:37 PM
snapdragon snapdragon is offline
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Well, it took a long time, a lots of puzzles, but the new EGR cooler bypass valve was fitted. It was £122 trade plus £75 for sundries, coolant, seals, pipes and unions etc.. also includes a new engine cover Audi emblem (£12) as the old one was lost before my ownership.

To keep the cost down, I didn't replace the seals between the lower manifolds and head and lower and upper manifolds as they were still quite deep and soft, I just cleaned them.

Now I get the engine light on and the same code as before but instead of intermittent it is every journey, but not a waste of time as the peformance is better with all that greasy soot gone, 2-3 valve ports were more than 50% blocked. I also removed that butterfly plate and stopped the smoke leaking out of the part I replaced. The EGR gas should now be cooled when it is supposed to be.
I still get the insufficient flow code but I did damage the thin vacuum pipes in several places as they had gone really brittle. I joined them together with red heatshrink tubing (see photo) and if the ends snapped off, just stuck them back into the rubber joints. I will order new ones but looks to be £90 for the set of 3.

Last edited by snapdragon; 23rd April 2020 at 09:19 AM.
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Old 20th August 2016, 06:50 PM
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Despite people not commenting, I think a lot of people have been following this thread. I have.
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Old 21st August 2016, 12:11 PM
Mechcanico Lee Mechcanico Lee is offline
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Yes I have been following it .

Snap , go into activations , active egr control and watch air mass reading drop , usually air mass reading will drop by half when egr open .

Does the 3L have swirl control is this operating ok ... again go into activations see if air mass drops when activated , swirls butterfly's normally closed at idle to get air speed up ,and open when revs over 2000 rpm or so

Egr causes so much trouble with the diesels .... manifold Black Death , ports blocked to death .....all the diesel cars I've as a power upgrade blank off egr and write out of the programs script .

Better mpg , runs better and no Black Death anymore
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Old 21st August 2016, 04:47 PM
snapdragon snapdragon is offline
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Cheers fellars!
I just went out to do Lee's tests and found another crack in a vacuum pipe it even snapped again when taking it off!
Attachment 14029

Attachment 14030

So I repaired that with some lawnmower fuel tubing and went for a drive and no more engine light or code so it must have been the fact there was no vacuum.

Attachment 14027

Lee, how do you activate EGR? If I go into output tests, the engine stops at the first test as that test is closing the throttle valve. The only way round that is to triple-click NEXT/ACTIVATE so it just does a big stumble and advances to the next test. If I get to the EGR test, I can't see the measuring blocks without closing that window down. I must be missing something.
In any case, actual EGR is alwayssignificantly more than specified...even before I started all this, maybe the VCDS labels are transposed?
Do you have any advice about how to activate EGR and view MAF?
Thanks.
Attachment 14028

Last edited by snapdragon; 23rd April 2020 at 09:19 AM.
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Old 21st August 2016, 08:02 PM
Mechcanico Lee Mechcanico Lee is offline
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Hello snap ,most times you can just skip through like you say and get to egr and actuate it , I've always found vcds is good for activations and puts up all relevant data blocks that's involved with whatever your testing......but no worries , just put air mass data block up , remove vac pipe off egr , if you have a length of vac pipe just just put it on the egr vaccum pod and suck on it with your mouth ( oooeerrr missus ) and look for air mass drop .

Sounds like the vac leaks was the issues though if now it's not logging codes .


Where you say about actual air mass being more than desired .....is that the case now that you have sorted the vac leak to the egr .


I've found if you leave the engine idling for a time egr normally turns off ( so closed valve ) just a blip of throttle brings egr back in so then you get the lower air mass reading .

Egr switches off at idle for a process called 'smoke limitation ' ...... bleeding exhaust gases in at idle makes the combustion suffer .

Egr is an inert gas ( does not support combustion ) if you watch what egr does in data blocks when driving you will see it opens the most on lite throttle loads .

Light throttle loads makes combustion temp go high ...... high combustion temps makes NOX gases ....hence bleed in inert gas to lower burn temps ........ what happens when gas burn temps are lower ....... soot particles produced ...... hence dpfs came along .

I'm going off on a tangent here arnt i hehe
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Old 23rd August 2016, 09:50 AM
snapdragon snapdragon is offline
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Thanks Lee
Since then, the code has come back again but no EML yet. That is how it used to be code would nearly always be there and then EML would eventually come on after a few days.

I found the other tests in Basic settings (not output tests)
The EGR would cycle on and off and I could see the EGR actual was always more than specified, and even so the EGR always seemed high as in even at it would only go down to about 280mg/St. and up to 420mg/St.

I will check the vacuum system with a vacuum tool and also block off and check the EGR valve operation and air-tightness and check valves etc....

Thanks again. Car is driving fine though and never any smoke.
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Old 23rd August 2016, 11:33 PM
Mechcanico Lee Mechcanico Lee is offline
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Your going the correct way , vac supply to solenoids will come from brakes vac pump or on the pipe that goes to the brakes servo .... somewhere there anyhow .

With vac guage at the brakes vac pump take off point I reckon 25hg of mercury sounds good .

Trace the pipe from egr valve to the control solenoid ...... test the vac at that point , if your vac is down at that point you are loosing it somewhere ..... if its the same as the vac pump reading I would suspect the egr control solenoid is leaking the vac off .

I'm assuming here but things using vaccum ..... Egr , swirl flap control, is inlet manifold strangulation flap electric or vac control ?? Not sure but don't think it has turbo intercooler bypass ( dozer valves ) it does have egr cooler bypass so all these just need ruling out that they not loosing vaccum
Turbo vnt mechanism ..... vac or electric? .... vac system normallly have a vac resvoir aswell .

I have a superb bit of kit at work for vac leaks or boost leaks ....smoke pro machine , just smoke it up from brakes vaccum take off and it will fill the whole vac system ..... just look for the smoke .

Keep at it your close to full fix I think 👍👍



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  #10  
Old 26th August 2016, 08:20 PM
snapdragon snapdragon is offline
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Thanks again Lee - looks a great bit of kit.

Only the EGR and cooler bypass flap are vacuum powered. The turbo VNT, intake flaps and throttle are all electric.
On 2008- models with 4 digit engine codes such as CABA, the EGR is also electric but the cooler bypass flap is still vacuum on those too.

I need to get one of those handy vac pumps - but in the meantime I found the one way checkvalve 046905291A allows air to suck and blow both ways I cleaned it out with IPA and some blackness came out but it is still not sealing inside so will order a new one.
I pulled a vacuum on the rest of the system with my oil extractor and it held pretty well but not perfect. It got dark but tomorrow I will pull a vacuum just on the cooler and watch the arm move and do the same on the EGR and see if I hear it snap shut when I pull the pipe off. It will be better when I get a handyvac with a guage.

Interestingly, with the vacuum blanked off after the brakes, I still don't get an engine light until part way through the second journey and the VCDS readings are the same EGR actual is greater than specified even though I know the EGR is shut tight and has a stiff return spring.
I have read in an SSP PDF that EGR flow is measured by lambda changes and only uses a drop in MAF reading as a fallback. My lambdas are always pegged at 99.9% as though they have been 'fixed' at that by ECU software that the previous owner did which may not help, but I had the car over 4 years before I got issues with EGR so I know it isn't the root cause.

Last edited by snapdragon; 27th August 2016 at 08:56 AM.
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