3.0 tdi throttle pause

[mhobson]

Had my A6 Allroad for over 4 years largely pleased with it but recently when you press the accelerator whether hard or soft at low or high speeds, there is an annoying pause before the engine pulls. Before you just had to touch the accelerator for an immediate response. VCDS shows no faults. Can there be ECU problems?

I look forward to constructive suggestions.

Thanks,
Michael

[AT.]

Before you just had to touch the accelerator for an immediate response. VCDS shows no faults. Can there be ECU problems?

It sounds like a turbo hole problem for me, maybe for some reason your charger has a slower response, or there could be a problem with the airflow.

I had a similar problem with my car. There was an air pipe in the engine area, which was almost full of soot, so my engine was even shut itself down, while there were no error codes in the MMI. After the cleaning of this pipe, I felt that the engine became stronger, so maybe this could be an answer for your problem too.

[mhobson]

Thank you for that, however the pause occurs before you would expect much turbo effect, there are no whistling noises which may suggest a vacuum leak and after the brief pause it accelerates a normal

[rowdy-999]

3.0 tdi rarely has turbo issues, just as ECU problems are again rare. Could be a throttle body problem, or maybe a throttle pedal postition sensor problem.

[mhobson]

3.0 tdi rarely has turbo issues, just as ECU problems are again rare. Could be a throttle body problem, or maybe a throttle pedal postition sensor problem.

Would those issues not have raised an engine fault on VCDS? Otherwise how would you be able to find the problem?

[rowdy-999]

Would those issues not have raised an engine fault on VCDS? Otherwise how would you be able to find the problem?

Not sure if this will help:

Manual throttle body adaptation:

"The Throttle is "Drive By Wire" and adapts to your particular driving style. Do a TBA Throttle body adaption).

1. Get in your car, it doesn't matter if you close the door or not.

2. Turn the key to the on position, the position just before the starter turns over.

3. Press the gas pedal to the floor with the key in the "on" position.

4. Hold the pedal to the floor for five seconds, then turn the key back to the "off" position(don't remove the key), then release the gas pedal.

5. Wait 2 mins. for a full alignment. During this time you may hear very faint noises and clicks. I
only heard one sitting in my car, if I got out and popped the hood I might hear more.

6. Drive the car as you always do.

Depending on your driving style, this may or may not be a big factor. I do a lot of city driving so
I noticed a big change after erasing my history. It is not hard to do this, just follow the
instructions - Key on, pedal down, 5 sec, key off pedal up, wait 2 minutes.

Keep the key in for the entire thing.

[AT.]

Thank you for that, however the pause occurs before you would expect much turbo effect, there are no whistling noises which may suggest a vacuum leak and after the brief pause it accelerates a normal

Honestly, I mean quite the opposite situation, maybe some air pipe is so clogged, that the turbo can't get enough air to spin up, and that may cause a delay. Your problem sounds similar to me, because there was no noise, or error codes in my case either.

[mhobson]

Honestly, I mean quite the opposite situation, maybe some air pipe is so clogged, that the turbo can't get enough air to spin up, and that may cause a delay. Your problem sounds similar to me, because there was no noise, or error codes in my case either.

I know what you mean, but I live in rural France, rarely travel in towns and the car has a DPF which I know is a pain and and gets blocked in city driving but particle readings are always low so I feel that the car runs quite clean, I normally get just above or below 40 mpg, and after the short pause on the throttle the car pulls as well as ever, the boost pipe is steel and quite big 10 or 12 mm so I expect it would nedd quite a lot of gunk to block it. The carvuses very little oil, I never have to top it up between oil changes.

[C6Allroad]

Symptomatic of a sticky EGR valve that is not closing fast enough.

[MarkTM]

Maybe worth looking at this thread as well

Good preventative maintenance and I noticed my throttle response improved afterwards

TB Cleaning Photos

Once I've bought my new manifolds I'll be getting an EGR delete and have the EGR mapped out...which weirdly costs the same as a full remap!?