Running issue 1.9tdi 130 - help?!

[L100NYY]

Hi guys I have a 2001 A4 1.9tdi 130 5spd which is having some serious running issues.

The car seems to suffer from some serious turbo lag and then all of a sudden it will boost and shoot off up the road, at times it would be downright dangerous as pulling out of junctions would be a bit of a lottery as to how much power would be available!!

Last week the car refused to tickover at all so I had the car recovered to my local Audi dealer. When the recovery truck arrived the Audi started but I still opted to get it recovered to them.

Now, Audi have looked at the car and cleared off a whole plethora of fault codes from the ECU and have subsequently roadtested the car and said it is now running fine.

I assumed it was a fault with the turbo but they are confident is fine. Should I be worried?

Thanks in advance for any responses chaps

[Rhostine]

I had a similar problem on my Passat recently. No turbo boost until about 2500 to 3000 RPM then fine. Also the car would loos e power up hill and have no turbo boost. Switching off and back on again gave me back boost at high RPM.

The garage replace the MAF (standard practise for power loss!) and another sensor related to controlling the turbo boost and waste gate control. Couldn’t tell you what sensor it was – sorry! The work was done by Wheelbase in Hersham if you want to try them.

Good luck
Marc

[L100NYY]

That's excellent, thanks Marc. I will speak to Audi and mention it and try and sound as though I know what I am talking about!

[Neil_Sc]

I had virtually this exact problem, 2001 1.9 TDi A4 as well.

My symptoms started by the car losing power at certain RPM's, I stalled it 3 times one weekend as the RPM's dipped at certain crucial moments.

At first, I troubleshooted it by unplugging the MAF sensor, if you unplug it then it goes into a default mode. If the car drives better it is thought to be a sign the MAF is knackered.

I unplugged and the car was better, so I ordered a new MAF, replaced it and plugged it in and the car was the same.

After further troubleshooting I found a turbo line from the top of the EGR valve was split and required replacing. You can do some good troubleshooting of the EGR by removing the hose from the top of it so it doesn't activate. (The EGR is that silver round thing showing through your engine cover)

I then run the car without issue for two weeks and then all of a sudden I was having issues. Started the car and the RPM's would just sink until it stalled.

I troubleshooted yet again by removing the vacuum hose to the EGR, this solved the problem. I found that one of the sensors which controls the exhaust gas was faulty. (This was the sensor that was at the other end of the vacuum hose which goes into the top of the EGR)

I replaced the part and reconnected and all was fine.

In between this I actually disassembled the EGR and took the intake manifold off and gave it a good clean.

Car is now running fantastically.

Edited by Neil_Sc on Wednesday 12th December 22:48

[L100NYY]

Thanks Neil, that sounds just like what I have been experiencing so it should be well worth a try to see if it cures the problem.

I am just concerned tha Audi are saying that there is nothing wrong with the car having claered the faults off of the ECU!?!?!

[Dr G]

L100NYY said:

Thanks Neil, that sounds just like what I have been experiencing so it should be well worth a try to see if it cures the problem.

I am just concerned tha Audi are saying that there is nothing wrong with the car having claered the faults off of the ECU!?!?!

That's main dealer speak for 'the computer doesn't know what's wrong and neither do we'.

[L100NYY]

Dr G said:

L100NYY said:

Thanks Neil, that sounds just like what I have been experiencing so it should be well worth a try to see if it cures the problem.

I am just concerned tha Audi are saying that there is nothing wrong with the car having claered the faults off of the ECU!?!?!

That's main dealer speak for 'the computer doesn't know what's wrong and neither do we'.

Too true! After 10 years of working in the trade that's what worries me!

[Neil_Sc]

I am very very very surprised that they have not said to replace the turbo by now, this is the most common thing for a main dealer to say.

They are far too reliant on vag-com these days, no troubleshooting skills at all.

[L100NYY]

Neil_Sc said:

I am very very very surprised that they have not said to replace the turbo by now, this is the most common thing for a main dealer to say.

They are far too reliant on vag-com these days, no troubleshooting skills at all.

Just as you were typing that I was on the phone to the Audi dealer, essentially they haven't fixed anything all that they heve done is clear the error messages off the ECU.

As I just said to them, this means that the car is only going to play up/let me down again so what is the point in me having the car back. With much cajoling I have convinced them to carry out more tests on the car whilst they have it there.

They wanted me to take the car back and then wait for it to play up agin and then take it back to them. Effin great idea that one. Whatever happened to good ol' mechanics that fixed cars huh?!?

[00161wj]

There trying to save you money by telling you to come back, doing this will mean only the faults which are causing this will be stored in the memory. Instead of replacing parts for old faults of things that may have simply been unplugged with the ignition on.
Good chance of an N75 and airmass meter fault though, with a possible EGR fault.

[Jem0911]

00161wj said:

There trying to save you money by telling you to come back, doing this will mean only the faults which are causing this will be stored in the memory. Instead of replacing parts for old faults of things that may have simply been unplugged with the ignition on.
Good chance of an N75 and airmass meter fault though, with a possible EGR fault.

Audi dealer trying to save you money?

Thats an Oxymoron if ever I've heard one, The standard cure for all EML faults is £125 a time fault clearing rather than fault invesigation.
Only my bitter and twisted view.

[philip walker]

As suggested the EGR valve is faulty. Remove the vacume hose from the EGR valve on the inlet manifold plug the vacume line and road test.
Replaced loads of the EGR control valves recently. Fairly cheap to replace.

[L100NYY]

philip walker said:

As suggested the EGR valve is faulty. Remove the vacume hose from the EGR valve on the inlet manifold plug the vacume line and road test.
Replaced loads of the EGR control valves recently. Fairly cheap to replace.

Thanks Phillip, I'm just about to phone Audi now to see if they have found that out yet!

[puffpuff]

I had something very similar with my TDI recently. The engine would drop to half power and the only way to cure it was to switch off and then on again - scary when overtaking in the outside lane....

Turned out to be a faulty N75 valve, (cost approx £28) + labour for dealership to fix.