2001 (51) Audi A4 B6 Avant 1.9TDI 130 AWX - No low rpm power (stalls, judders, hesitates), idles fine

[wutr]

Hi, here's my problem and I hope you can provide me with some insight:


The vehicle:
December 2001 Audi A4 Avant (B6) 128.000 miles


The Engine:
1.9TDI 130 AWX


The Problem:
When stationary: The engine hesitates when reving from idle. This results in a judder and sometimes a clearly audible rattling sound from the engine.

When driving: Acceleration is poor or the engine stalls. Second gear causes the car to judder significantly, accelerating from low RPM is therefor not possible.


Done so far:
Replaced the fuel filter.


Additional information:
The problem occured when driving in moderate rain. The fuel tank was not full, but not entirely empty either. The onboard computer gave a range of 80 miles. The next day I decided to fill up the tank with diesel, but I aborted my journey before getting to the busy roads, because I did not trust the car to make it all the way. Here I replaced the fuel filter. The symptoms persisted however.

Furter investigation reveiled the engine to rev smoother when the Intake Manifold Flap (black vacuum controlled actuator next to the EGR valve) was manually moved to the position opposite of it's position with the engine idling.

When driving back home, up a hill, I tried to keep the revs up so there would be sufficient power to get me there. This was in second gear. The engine started slowing on a steeper incline doing about 2500rpm. Kicking the accelerator resulted in the engine picking up, being boosted, and the car accelerating again. This was observed by the car behind me as a single cloud of black smoke, but clear exhaust afterwards.


THE QUESTION:
Unfortunately I have not got access to a code reader. I would like to know if anyone has had any experience with this problem though, or whether anyone can tell me about possible causes. It would be greatly appreciated!

[zollaf]

welcome to the forum.
you say you don't have access to a code reader.
this is unfortunate because you need a code read to go any further. you could randomly start replacing bits, but you could actually get to the point where your engine bay is fully rebuilt before you fix the fault, which could be a £10 coolant sensor, or an AMM.

[S66MJETDI]

Where abouts are you....... perhaps myself or someone else near to you could assist with code reader?

[wutr]

Where abouts are you....... perhaps myself or someone else near to you could assist with code reader?

Devon, if that's any help...

I'm happy to invest in a code reader, but my budget is very small The best option I've come across is to start with a USB > CAN cable and use VCDS Light, but I'll discuss that in another thread so this one can be kept for the actual problem at hand.

[zollaf]

explore the vcds section and you may find a local member with vcds who can help you.

[wutr]

Right, I've looked on the VCDS Users MAP and it's not too bad. 30 minutes away or so, but bear in mind that I can't really drive my car anywhere in the hills.

I've started a thread as to which cable would work with my car and VCDS Lite. I could not find too much info on the forums so I hope someone found one that works:
VCDS Lite cable experience - Audi A4 B6 (Dec 2001, 1.9tdi 130 AWX)

[nevo]

Here's something you could try first,the egr actuator you're refering to,is it the one with the diaphram and small black rod???,if so remove the boost pipe and check its operation by removing the 1/4" vac pipe and suck on it with some other pipe,also detach the rod and operate manually see if it operates smoothly and returns to the fully open position,just something to try before you get a code scan.

[zollaf]

i had a golf with that rod snapped so the valve was closing. that lost rather a lot of power until 3 small cable ties fixed it.

[wutr]

RE: the manifold flap actuator rod. I remember the rod / actuator moving after shutting the engine down. It looked like it was functioning properly.


Today I finally had time to have another look at the problem, and the diagnostics cable I ordered (see my other thread) arrived as well. I plugged it in and fired up VCDS Lite. The Engine module said: 0 fault codes. I ran the auto test (it tries Engine + Brakes before telling you off for not registering) and again: 0 fault codes. Since the last I knew was that the engine had the problem I described in the opening post, I thought I missed out on something with the VCDS config.

I started the engine to see if that would produce any faults. After a minute or so on idle RPM I revved it up to about 2000rpm like I did a couple days earlier. However, no hesitation, no juddering, no nothing. Smooth as it used to be and again 0 fault codes.

Took it for a test drive, filled it up with diesel and floored it in 3rd and 4th gear after about 30 minutes driving. At first there was some smoke, but the second time I couldn't see any in the rearview mirror.

The only thing I could think of that explains why it sorted itself out is that there is a dodgy connection / connector somewhere which was influenced by the dampness a few days ago. It has had no rain since. Question is: which one? (if it is a connection at all)

[suman666]

I have an Audi A4 TDI B6 2001 with AWX. Which also has powerloss problem in Low rev. This car is low on power most of the time. Specially when it rains or I goto a automatic car wash. Say if I start the car I feel the car produces only about 20% of the engine power. Nothing happens if I floor the accelerator or half. The car moves slowly until it hits 2500 rpm and then it shoots like a rocket and lot of black smoke comes out. It is frustrating when there is traffic jam.
I took it to the garage, they cleared the plenum chamber for any blockage, tested the vacuum lines with smoke, checked EGR and MAF found nothing wrong. I ran VCDS diagnostic at-least 20 times over last year. No fault. But still the problem starts if I goto a automatic car wash. I don't know what to do and how to find out the fault.
As your problem seems very similar to mine, if you find any solution please share with us. Thanks