Car over-revving erratically

[trapdoorsally]

Hi All,

I have a 99 A3 1.6 with 60K on the clock which has recently started to rev up on it's own accord reaching 4,000-4,500 revs on one occasion whilst idling and 3,000+ revs when cruising in 4th and 5th gear today. When it first happened I assumed that the accelerator must have been caught on the car mat - but this isn't the case, I'm obviously worried that this is going to cause damage if it doesn't get remedied soon, but don't want to rely on my local Audi garage!
Could it just be a sticky acc pedal?
Any advise would be great thanks guys................

[STEWY L]

all i can offer is something that happened to an old car i had once.
the earth lead from the engine to chassis had come off, and it was earthing through the
throttle cable, burning it at the same time, causing it to stick.

[trapdoorsally]

Thanks Stewey, I'll certainly look....

[omegadirective]

Have you had your throttle body cleaned out recently?

If you have - it might need to be re-calibrated electronically using VAG-COM or similar.

If you haven't - it might need cleaned out. Throttle bodies build up dirt over the years and are known to stick when too dirty.

[revo_20vt]

Hello mate it sounds like the Idle Control Valve needs cleaning or replacing, If when you are driving at say 30-40mph and you push the clutch in and coast, when the revs drop to idle speed will they then shoot straight back up and then down again and so on :boggled:

[Crasher]

That car will have an AKL engine and they don’t have an idle control valve, the idle is controlled by the throttle body stepper motor. As omegadirective suggested, the first step is a throttle body clean and then the TB will need re-adapting to the ECU using something like VAG-COM. However, the AKL engine can be a real pain for idle problems and as well as re-adapting the ECU, it may need to have its learnt values erased in Adaptation 10, group 00. Even then the AKL can be one of the few engines that often requires a new throttle body and even then they can be a pain to get to settle down and adapt, they even make me start pulling my hair out.

[revo_20vt]

Crasher's the man 2 listen 2, ive been out witted by the crashmeister.:biglaugh::Blush:

[Crasher]

Der Crashmeister, sounds good-means I am good at crashing-well I used to be!:D

[revo_20vt]

Same mate, but not always my car, I got a bit carried away in my mates smart fourtwo in to a sharp left hander with dyer consequences, not good when the crumple zone is your legs:aargh4::crying::eek::puke:

[omegadirective]

That car will have an AKL engine and they don’t have an idle control valve, the idle is controlled by the throttle body stepper motor. As omegadirective suggested, the first step is a throttle body clean and then the TB will need re-adapting to the ECU using something like VAG-COM. However, the AKL engine can be a real pain for idle problems and as well as re-adapting the ECU, it may need to have its learnt values erased in Adaptation 10, group 00. Even then the AKL can be one of the few engines that often requires a new throttle body and even then they can be a pain to get to settle down and adapt, they even make me start pulling my hair out.


:biglaugh: You told me most of that...

I wish I could afford to upgrade to a 1.8T or something. The A3 is a lovely car, but let down by the 1.6 engine.

[revo_20vt]

sell ure audi that u have and get 1:biglaugh:

[omegadirective]

Lol, I would if I could!

I'd only get around 3-4k for my car and to get a decent 1.8T (Quattro hopefully) I'd still be looking at 5-6k, more if in mint condition. :(

Hard to earn that money when you've just graduated from uni! :p

[revo_20vt]

I got my a3 1.8t about a year ago, 1998, full leather interior, FASH, 60,000miles,BOSE sound system, I paid £4.300 and its never let me down, I was 19 with 2 years NCB and i paid £850 fully comp insurance:approve:

[omegadirective]

Not bad! I'm almost 21 with 3yrs NCB and my A3 is costing me £630 FC. I have a 2000 plate.

Next year I'll look at a 1.8T Quattro, or S3 depending on insurance. Should be earning properly by then!

A4 would be nice though...

[trapdoorsally]

Thanks for the advise guys, I've managed to source a local garage through a friend of the head mechanic, they have the diagnostics and he knows of historic faults similar to mine......I'll let you know.

Thanks again

[Space Cadet]

It was good advice to clean the throttle-body, but as far as I know you can re-set it by disconnecting the battery for say 30 minutes, it will re-set itself over the next few miles.

Would be worth using some petrol additive injector cleaner as well.

[Crasher]

Disconnecting the battery clears the adaptations and settings meaning you HAVE to reset in Basic Adjustment 04.

[trapdoorsally]

Thanks guys, cars in the garage tomorrow so should know more then. I have noticed the car also doesn't like a warm start. If the engine has been off for 5mins it takes a few attempts to get it to restart.....once it does the cars revs shoot up - I'm hoping they're both connected??

[Crasher]

It will probably have a coolant temp sender fault stored.