Audi A3 1.6 SE Over Revving

[boxy32]

Hi Guys,

I'm new today so apologies if I post in the wrong place.

I was wondering if anyone could help me with a problem I have on my A3.

The Car:

A3 1.6 SE '03 42000 Miles

Background:

Replaced temperature regulator and thermostat. Work done by Audi dealership.

1000 miles away from a service.

New middle and back exhaust 4 months ago

The Problem:

If I gently rev the car to 2000rpm the engine will over rev and not drop below 2000rpm and will fluctuate between 2000rpm and 2500rpm.

I can rev right up to about 1800rpm with no issue.

If I turn on the air con it will return the engine to idle. I.E. A load on the engine seems to resolve the issue although it will return immediately if revved again, with the air con in both the on and off position.

Obviously, apart from it being embarassing when I pull up anywhere, it fails the MOT because you can't get a emission readings at 2000rpm

if anyone can help I'd be very grateful.

Rob

[gixxerk4600]

so when ur driving down the road, if you put the clutch down does it still rev high! i had a similar problem with an old car of mine! it was the air intake module! im not too sure why it caused this problem, i replaced it and still had a similar effect, i disconnected battery and re-connected it after a few mins and all back to norm!

[boxy32]

Hi Gixxerk4600. You're right, if I dip the clutch whilst urban driving (30 - 40 in either 3rd or 4th) it will still be revving from 2000rpm to 2500rpm constantly up and down, up and down.

Sorry for sounding like a c*ck but when you say air intake module, what exactly do you mean and is it easy to fit?

Rob

[omegadirective]

Check the throttle body. Mine needed cleaning before it would rev normally again. Make sure it gets recalibrated with VAGCOM or similar!

As posted above, the other thing I know can be a factor is the Mass Air Flow sensor. Maybe get that checked if you haven't already?

I have just recently had the over revving return and am unsure what it is. I just blip the throttle for a couple of seconds and it will return to normal. EVERY time I start the car it revs around 1,200 RPM for me before I introduce a load to the engine.

EDIT: Just seen your latest post. Sounds like it could be either the throttle body or the MAF. My car used to constantly accelerate even though there was little or no pressure on the accelerator and it just got worse when the clutch was dipped, obviously.

[boxy32]

Okay, thanks for the reply. The strange thing is, when I took it for the thermo replacement, I mentioned to the dealership about the over revving and when they returned the car to me they said that it hadn't happened while they had it. So I assumed the problem had been the temperature regulator and thermostat, then two days later, it was over revving again. I'm thinking there is a conspiracy and thet this is a problem that can not be fixed. . . .

[gixxerk4600]

it basically reads how much air is being drawn into the engine! and by that reading the ecu will compensate with a certain amount of fuel to give a correct fuel to air ratio, so urs may be reading high and the ecu is providing the engine with more fuel than needed causing it to over rev! does it happen straight away or after a few minutes driving?

[omegadirective]

I think it's something they don't WANT to fix. The more trips back to them you make, the more ££ they get. I'd get VAGCOM to check it out, see if it comes up with faults, then get the closest independant audi specialist, or a local garage you trust to check out the problems!

The MAF is supposed to be simple enough to replace and the throttle body isn't too hard. Labour is the most expensive part.

[gixxerk4600]

also forgot to say, may old car which had this problem was a fiesta n was very easy to fit, it was between the throttle bodies and the air filter! usually it should be nearer to the air filter! and it shouldnt be too hard to replace as there isnt to much to be taken off!

[boxy32]

Cool, thanks for the info. The last time I worked on the engine of a car was in 1990 with I had a Nova GSi . . . lol . . . what is a VAGCOM and where would I go about getting hold of one??

[gixxerk4600]

you can either buy one or take it to a garage and if there nice they could do it for free! they basically plug into your car and can read what is going on with anything and will tell you what the problem is! i recently had an emmisions problem didnt have a clue where it was coming from! they computer found it was an air leak on the intake side and when i had a closer look a found one of the rubber sleeve/collar things was not fitted correctly.