Revving problem with 2007 s3

Wezcubbages3

Registered User
Hi, last couple of months I've noticed that when I come to traffic lights ect and I come to a stop, my car seems to rev on its own to around 1500rpm. Also I found out ... I know it's stupid but when I pump my brake pedal it revs again. :s I cannot think what the problem is. I have a milltek cat back. Itg induction kit , forge spacer valve and I'm running MTM stage 1. Does any one know what the problem is ?
Thanks
 
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mjr901

Guest
Brake pedal shouldn't affect revs I don't think.

On my 09 S3 I had the forge spacer on and to be honest it really spoilt the car. always seemed to rev funny with it on. I also blame my map but MTM are pretty reputable...so doubt it's that. try taking that spacer off. seemed to work for me and less turbo lag with it off. Doesn't even make that good ' a noise really.

Other than that make sure air mass sensor is all dandy.

Mike
 

warren_S5

Moderator
Moderator
VCDS Map User
I had this issue on my last S3 and I could pump the brake pedal and the revs would rise! never worked out what caused it. Sometimes I'd pull up at junction and throttle would surge. Only thing I was wondering was tumble flaps in manifold as I'd had an error code (intermittent), but didn't change it. mAF could also be a culprit, but I never saw DTC.
 
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mjr901

Guest
How strange :-/ surely the braking system is pretty separate...?
 
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mjr901

Guest
The Germans have probably done something completely nerdy. can't see the need for borrowing a vacuum, master cylinders and slave cylinders, A.B.S pump and all that stuff I thought handled that sort of stuff, I'm definitely know expert though!
 

jungleman

Registered User
i had an inconsistent idle on my S3, but that wasn't linked to the brake (cool trick though) mine was cured with a new MAF but the brake link would make me think possibly not the MAF?
 

Wezcubbages3

Registered User
Another issue that I think is abit strange, when I give the car abit of a rev to around 4 or 5000 rpm. It seems to take forever for the revs to fall back down . Any one else had this problem?
 

warren_S5

Moderator
Moderator
VCDS Map User
Nope, didn't get that.

Best advice would be to go to a well respected VAG independent like Stattlers and get them to hook it up and run some basic tests.
 
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mjr901

Guest
Another issue that I think is abit strange, when I give the car abit of a rev to around 4 or 5000 rpm. It seems to take forever for the revs to fall back down . Any one else had this problem?

I had exactly that after my remap. it made gear changes horrific. it was a crap map. Viezu. I.e chipped uk. I took it off before I sold it. perfect again
 

essIII

Registered User
Another issue that I think is abit strange, when I give the car abit of a rev to around 4 or 5000 rpm. It seems to take forever for the revs to fall back down . Any one else had this problem?

So my '57 plate S3 was behaving similarly to yours recently. I had the 1500rpm at traffic light issue, along with the car clinging onto revs after I blipped the throttle.

Can't say I made the link between brake pedal & revs though - although I can't see why I would've been pumping the brake pedal to be honest!

Long story short, I replaced the PCV system with a catch can that I picked up off the VAGOC forums, and the car is back to normal. I can only assume that the issues were caused by a vacuum leak.

I'm sure I've read people talking about testing for this by trying to remove the oil cap from the engine, while it's running. If once you've unscrewed the cap it feels like it's being held down by a vacuum, then you've got a leak..... although it would be great if someone more knowledgeable than me could confirm that!!
 

LucasS3

Registered User
Try what eslll says, if you leave the car running and try pulling off the oil cap and there is a strong vacumn pulling it back down then it sounds like the problem I had. Go back a page and I started a thread called "revving on idle" it was the breather valve, which was £50 from Audi, then fitted it in less than 10 mins, very simple job, if you can get the engine cover off! Some very helpful info on that thread, sorted my problem out right away.
 

DaveyB

No misfires.
Just had this problem myself. Took to my local independant to sort at the same time as a 10k service, which was really only an oil and filter change. They replaced the breather valve, gasket and hoses. System scanned fault codes deleted. My mechanic also mentioned about reflashing the system as it learns and alters ratios from the fault. It also turned out that i had a misfire on all 4 cylinders.

Total bill came to £357

Cant wait to take it for a spin, might even get a clean!
 
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