Engine, Gearbox And Brake Issues - Common Faults?

[MrSparks]

Hi all,

I've got my car (8V A3 Sportback S-Line 1.8 Manual Petrol) booked at Audi this coming week, because of a few issues. This is my first Audi and i'm apprehensive about if the dealership will fully investigate the issues/fob me off. They have been great so far and will be giving a curiosity car for two days whilst they look into the problems. So that a good start I guess!

Here's a list of the problems. I wonder if anyone else on the forum has come across any of these before?

1. Power issue from cold: When I first set off in the car at slow speed and low revs, after a few seconds the revs drop or increase momentarily which causes the car to either drop in speed or accelerate. The acceleration is the big problem, especially if i'm maneuvering around a car park.

2. Occasional power hesitation. Periodically (regardless of the revs) there's a flat spot / hesitation in acceleration. I typically notice this when the car is warmed up.

3. Brakes grab. For no apparent reason when I brake and the brakes snatch/grab and I nearly go though the windscreen. Typically the bakes are nice an progressive. I can't see a pattern to this.

4. Clutch takes ages to disengage. The biting point is a the top of the peddle and disengage is at the bottom of the pedal. Even after fully depressing the pedal I can feel that the clutch is still slightly engaged. I'm having to change gears very slowly (2 seconds per change) to stop the gear box getting trashed.

I think 1-3 might be a engine management fault or a software issue maybe? I'm thinking item 4 could be either synchromesh or a brake fluid issue?. I reported the clutch biting being very low when I picked the car up from new, but the mechanic said that was normal?!

Thanks in advance.

 

[veeeight]

3. Brakes grab. For no apparent reason when I brake and the brakes snatch/grab and I nearly go though the windscreen. Typically the bakes are nice an progressive. I can't see a pattern to this.

This is typical of brakes not being bedded in fully/properly. I had this grabbiness on mine. In summary - you have uneven pad deposits on the disc.

I solved it by doing, in quick succession, (on an empty dual carriageway) 6, 70-0 aggressive stops, to get rid of all the uneven deposits. Then drove the car normally a further 10 mins to cool down.

Brakes have been fine and non-grabby every since.


In more depth:
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

 

[veeeight]

1. Power issue from cold: When I first set off in the car at slow speed and low revs, after a few seconds the revs drop or increase momentarily which causes the car to either drop in speed or accelerate. The acceleration is the big problem, especially if i'm maneuvering around a car park.

2. Occasional power hesitation. Periodically (regardless of the revs) there's a flat spot / hesitation in acceleration. I typically notice this when the car is warmed up.

Similar symptoms here:
http://www.audi-sport.net/xf/threads/clutch-problem-a-bit-of-advice-needed.222825/

Points 1&2 (and poss 3) certainly have been discussed on this forum before, one of the solutions was to "just give it more gas", but do please do a comprehensive search as there were a few threads on this.

 

[MrSparks]

Ok, so the dealer was unable to locate the intermittent faults but they will be reporting the brake problem to Audi as a safety issue.
The good news is. i'm not going mad. The dealer gave me courtesy car, which was the same spec as my own car. The courtesy car behaved very differently to my own car. It was more powerful, the power delivery was smooth and the gear change was defined and crunch free..

The bad news, despite the above the dealer can't help unless they see the faults occurring for themselves. I've informed the dealer I'll work with them until the end of September to locate the faults... at which point i'll reject the car if the issues aren't sorted.

Does anyone have experience in OBD logging and analysis? I would like to graph the engine data and show the dealer where the faults are (in graph form). Specifically Engine RPM, Throttle Position and Road speed.

 

[Tom8VA3]

3. Brakes grab. For no apparent reason when I brake and the brakes snatch/grab and I nearly go though the windscreen. Typically the bakes are nice an progressive. I can't see a pattern to this.

Could the above problem be related to the kinetic energy recuperation system? I know there is a small grab feeling as recoup system kicks in when small amount of pressure applied to brake pedal.

 

[veeeight]

Sounds more like a servo issue.

But in general, Audi brakes are typically over-servo'd, but they shouldn't be grabby.

http://www.audi-sport.net/xf/threads/brake-pedal-issue.206333/
http://www.audi-sport.net/xf/threads/audi-a3-brake-pedal-petition.230193/

 

[Ignition1]

4. Clutch takes ages to disengage. The biting point is a the top of the peddle and disengage is at the bottom of the pedal. Even after fully depressing the pedal I can feel that the clutch is still slightly engaged. I'm having to change gears very slowly (2 seconds per change) to stop the gear box getting trashed.

I had that problem when I test drove a manual A3. I found the clutch unbearable - biting point too high, disengage too low - my ankle will be worn out with the amount of travel the clutch pedal has to make. Plus it has 6 gears and it constantly kept flashing at me to change up...not for me.

 

[mjcourtney]

3. Brakes grab. For no apparent reason when I brake and the brakes snatch/grab and I nearly go though the windscreen. Typically the bakes are nice an progressive. I can't see a pattern to this.

Could the above problem be related to the kinetic energy recuperation system? I know there is a small grab feeling as recoup system kicks in when small amount of pressure applied to brake pedal.

If you have cruise control set, and are going down hill then the brakes are applied automatically to maintain the speed. If you then break normally you'll find they 'grab' as they are already engaged. I suspect if you make a conscious effort to break gently when cruise is set you'll find this problem disappears.