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Audi a6 3.0 TDI Fuel problem and DPF warning

Audi A6 C6/4F
Themenstarteram 16. Januar 2020 um 12:44

Hi, I try to get help here! Im from sweden but have got no info here who can say the correct sollution without change every part of the engine.. Hope english is ok :D

 

I ran on cruise control and suddenly the glow plug light came on and started blinking , i lost power and if i give throttle the engine "pulsating"

if restart car, the light come off until i give extra thottle then it came back.

I drove like this for 1 week and it got worse and worse, more pulsating engine.

I changed the Fuel pressure sensor on the fuel rail, left side. and fuel filter.

No change. I drove it to the mechanic (30 km) Now the particle filter lamp started to warn. I continue and mechanic can only see fuel pressure problem in computer, nothing else. So i got not so much help there.

Im on the way home and then the car start with heavy pulsating 10 seconds then dies. I got to go back home with the towing rope.

 

At home it can start some seconds and then die.

 

I checked fuel pressure "fuel tank low pressure pump" and its 4 bar i guess thats ok.

 

I got error codes :

P1063 Fuelpressure the highest value is reached

P1063 Fuelpressure the lowest value is reached

P1063 Fuelpressure short circuit to plus

P1573 Valve left enginemount cut down

P0501 vechicle speed signal not correct

I have swedish OBD program so i tried to translate as good as i can..

If i delete codes and drive, then P1063 is the one that always come back, the other 2 can stay away for longer time.

I guess its fuel problem that now maybe clugged the particle filter?? Or can it be only the particle filte?

If anyone have idea what i should do please help me!!

Thanks

/Rick

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22 Antworten

Hi there,

don't know your programm, but assume it should be able to provide actual values for particle filter pressure loss ( with VCDS channel 72, 73 or 75, don't know precisely, approx 10 mbar idle and 200 mbar full speed ) or the injection pressure ( if I remeber correct, in the range of 600 - 1900 mbar )

With that you should be able to localize the problem a little bit more.

Let us know....

Ploetsch10

G‘day,

 

Seems like you’ve got a few issues there. The injection pressure on a facelift model should go up to 2000 bar not mbar. The 3.0 TDI has two fuel pumps btw. One lives within the tank (electric and 4bar sounds reasonable) which serves a high pressure pump that is bolted onto the engine producing the up to 2000 bar. It’s pretty much the first component on the engine in the middle front. It has a toothed belt drive from the left (in driving direction) DOC (Double overhead cam) powering it. On the rear you should see the high pressure lines which serve the rails.

 

Also of interest would be the loading of your DPF (Diesel Particulate Filter). Can be found in the ECU (engine control unit) channel 104 (First value is of most importance for now but if you can, just send all four).

 

Short circuit to plus defines an open circuit ... e.g. a bad contact, broken wire etc.

 

I‘m a bit confused as to why the lowest and highest value was reached.

 

Worst case would be a faulty high pressure fuel pump. But I’m not a professional mechanic who could make that call!

 

@ploetsch10 , channel 72 - 77 are the time correction values for the injectors... they only adapt in large km-driven intervals. Don’t think we’d be able to see much here. But open to learn something :)

 

Cheers

 

Edit: after changing the fuel filter, did you purge the fuel delivery system? Can be done apparently by turning the ignition to on/off 3times or with VCDS.

 

Edit: It also seems like that your left engine mount is bad... but check the wiring harness first.

May I correct the rail pressure values? The second gen. of 4F (facelift) V6 diesel engine is running at high pressure in the range of 250...1800 bar. It depends on the engine load and engine revolutions per minute.

@Rillopro Like A6Aussie wrote you should check the tooth belt of the rail pump. Replace the fuel filter is also a good idea. I hope your rail fuel pump is without any damages. Some users did have some trouble getting "eating-it-self-pumps" at the 1800 bar CR system.

But I would also proof the correct functions of the rail pressure sensor and of the the electric driven pressure valve mounted at one of the both rails (I do not know the correct side - left or right).

During the time the electrical engine mounts are getting out of order. One of my both mounts I renewed 2015.

Themenstarteram 3. Febuar 2020 um 22:05

Hello, thank you for all answers!!

I have OBDeleven in my garage and i manage to get this values from DPF :

I got the car running approximately 10 seconds to make these values on idle.

It dies, but i can restart and it working some seconds again.

 

Anybody who can tell me what this values means?

Attaching pictures.

Thanks!!

83820731-3420524228020833-6002972667454423040-n
84350264-162537508516070-6651517165851639808-n
Themenstarteram 3. Febuar 2020 um 22:14

I also got this code again for Left engine mount and it dont go away..

I start wonder if it could have anything to do with the fuel problem??

 

84393540-172976873962387-2842518616165842944-n

The partikle filter values are ok, the difference pressure is not as high as you can assume the exthause gas path is blocked. You should clean the particle filter but it is not the problem in my opinion.

Check the fuel pressure, rhe rail pressure and the rail pump toothed belt. For getting the rail pressure values the engine have to run (idle).

Hi @a3Autofahrer so far I recall, the values for the particulate filter are lower. From memory the pre-facelift (... - 2008) goes up to 0.46l and the facelift model (2008-2011) only up to 0.36l. This would strongly suggest that the DPF has had it and needs to be reconditioned or replaced considering it's value is 0.55l.

 

Don't worry about the engine mount for now. It's either shot or you've got an electrical problem. It won't cause your symptoms though I wouldn't think.

 

How did you go checking the rail pressure?

 

Cheers

@A6Aussie You are right that the long term particalate filter values (ash) exceeds. But it is in my opinion not the reason for the failure.

Themenstarteram 5. Febuar 2020 um 15:35

Then i guess that DPF is little bit stuffed but still, its because the engine is not running well so i should found that problem first.

 

How do i check the fuelpressure, rail pressure? I have OBD eleven, anyone knows if its possible to check with that?

I will look into that belt!

 

The fuel tank pump i have checked, it showed 4 bar and gives good fuel when running the starter.

Using your OBD eleven you should able to open the ECU - the engine control unit. Just proof the values stored in the block numer 22 subblock 2 und 3. Subblock 2 is the setpoint and 3 is the measured value.

I think you can read out several values and check the plausibility. For instance the temperature values and pressue values and so on. I think the rail pressure should exceed 200...250 bar to get the engine running. During idle running the pressue is about 240...400 bar.

Themenstarteram 5. Febuar 2020 um 21:42

Hey,

Im happy now after doing what you smart people says.. I looked at the belt for rail pump and you said tooth-belt? i see no teeth :D

So thats making me really happy.

I had to lift some air tubes, and when cranking it doesnt start but the belt is working and pump is spinning.

I put the tubes back and did not start maybe its on the limit of getting fuel..

It must be this problem right? Still i dont know why the pump is rotating with the belt anyway, then it should get fuel?

Thank you so much so far.

(Attaching videos of the pump/belt)

https://www.youtube.com/watch?v=L2MluT4thwE

https://www.youtube.com/watch?v=wKUUUy1FQHQ

84215110-904997696563709-1438032798198792192-n

Holy cow!!!

Never seen that before... but then, I am not a mechanic.

How many km's did your car run so far? For this toothed belt to be that worn I'd be surprised if this would be normal wear and tear. So best to get a new belt set with tensioner etc.

I've seen some info in this forum before where it was mentioned that the facelift models have a synchronised rail pump. You basically have to align the pump and the cam (the cam drives the belt) to a certain position as the fuel pump introduces pressure waves into the rail system feeding the Injectors. I guess I could find the treat dealing with this and link it here but it's in german. If I get time I might translate it for you later on.

But yea, definitely a big issue there ;-)

Cheers

There is no synchronized rail pump. Because it is the first generation of common rail V6 Diesel engine. The second gen. V6 TDi was released in A6 4G. Just install new belt parts including the proper belt. :)

@a3Autofahrer I stand corrected. I just flew over one of the old threads and there was a long conversation about it with the result that the 4f is not synced yet.

Looks like you contributed a lot to that thread as well :)

Cheers

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