S3 revving by itself, pcv changed what next ?

R222cet

R222cet

Registered User
Joined
Feb 7, 2017
Messages
218
Reaction score
35
Points
28
Location
Rochdale
Hi guys seems an awful lot of people have this problem but it seems to be fixed with changing the pcv. I've done this today replacing the pcv and gasket and I still have the problem :/ So what's next to check ?
The car seems a little rough on idle and when I'm coasting up to the lights and come to a stop the revs Will rise to around 1.3k and go back down and on the odd occasion it will do this 3 times in a row ! Only seems to do it when engine is up temp aswell.
It's driving me mad now any help is appreciated
 
  • Like
Reactions: garethrees
Have you tried taking the MAF sensor out and cleaning with some contact cleaner? Mine had the same problem and I cleaned the MAF sensor and replaced the PCV and it was fixed. It's a much quicker job than the full throttle body so might be worth a shot first.
 
I'll have a look at my maf now tbh car is a 2010 and done 41k so maybe that. If u unplug the sensor and take it for a drive will it through a warning light on the dash ?
 
On the inside of my fuel cap it says min Ron 95 and 98 premium. I've been running she'll v power which is 99 will this make a difference surely 100s of people on here will use the same fuel, just an idea
 
R222cet said:
On the inside of my fuel cap it says min Ron 95 and 98 premium. I've been running she'll v power which is 99 will this make a difference surely 100s of people on here will use the same fuel, just an idea
Click to expand...
99ron is a cleaner fuel so cleaner intake.
Clean your maf sensor with electrical cleaner and take your throttle body out and clean with carb cleaner to start.
If this doesnt work then you will need to start on your injectors and coil packs. You might have a leaking fuel injector seal, so a seal kit might be needed or one of the injectors might be faulty.
And lastly you might want to think about walnut blasting your inlet valves as they get furred up with carbon deposits, which is a byproduct of the tfsi and tsi (Stratisfied) injection systems.
 
I'll get at my maf sensor today and have a look/clean it then I'll look into throttle body. It did have a fault code can't remember the code but it was something like 'idle higher than expected'

On cold start when it sits at 1,100 rpm it's seems fine with a little Rev the needle acts normal. But when the car gets warm and the Rpms drop to 800 it's the 800-1100 that feel a little lumpy
 
I have exactly the same issue as you describe, perfect when cold but once at operating temperature revs sometimes don't drop as fast as they should. 90% of the time everything is fine. Replacing the pcv improved things a lot. I have since then done a carbon clean, cleaned the injectors, replaced all seals and gaskets for injectors and manifold, replaced spark plugs, cleaned the throttle body and intake flaps and realigned both with vcds. Never had a single fault code either.

Will be trying the maf sensor clean next, if that doesn't help then it is probably something wrong with the throttle body/throttle position sensor...
 
I'm literally waiting for the sensor to dry out so I'll report back. Not holding my breath tho.

I've just taken my engine cover off and I can see the air filter poking out around the edges is that normal ?
 
Thanks for the update! As for the air filter, I have a hard time remembering exactly how it sits inside the engine cover as I run a revo intake, The cover splits in two held together by 10 or so screws, so easy to check the fitment with the cover off :)
 
thanks for that. I'll do it tomorrow and hopefully it helps but I'm just confused as to why it only feels rough and I get the revs bouncing when the car is warm
 
Does sound like a fuelling problem.
If the butterfly's aren't closing properly after the choke closing, but then it could be one of the injectors playing up, out of interest have you scanned for fault codes?
 
Yeah a fault was found

001287 - idle control system RPM
P0507 - 001 - higher than expected
 
R222cet said:
Yeah a fault was found

001287 - idle control system RPM
P0507 - 001 - higher than expected
Click to expand...
Take look here, 16891/P0507/001287 - Ross-Tech Wiki
Id say you have a possible vacuum leak somewhere or it is indeed to do with the throttle body or sensor.
So nexy would be to take off the throttle body and give it a good clean including the connector and if no luck there then check for a vacuum leak, if no vacuum leak then you probably have a faulty throttle position sensor.
 
Hi lads following this with interest as my car does this sometimes rev on its own , getting loads off good info so please keep up the good work and if you finally work out what it is please share , just a little note when I mentioned it to my Mechanic ex Audi guy he mentioned to me to check my dip stick and check the little rubber O'ring was there cause if not then it is not sealing correctly and can allow the engine to suck in air , I need a new dip stick
 
It's fairly common but there can be many different issues causing it unfortunately. From my research the most common fix is the pcv valve failing. Mine has been really bad today the worst it's been since owning the car
Next for me will be getting it to a vag specialist and get them to clean throttle body,recheck for vacuum leaks check a few sensors and get them to have a look at the injectors
 
Could it be coolant temp sensor ? Can I check this by pulling the sensor out when the car is running ?
 
The coolant temperature shouldn't have anything to do with fueling or throttle control, easy to check with vcds when car is cold (reading will be very close to ambient temp).

Checked my dipstick today, not only is it missing half of the plastic, the o-ring is also gone, possibly causing a small vacuum leak. Cleaned my sump and oil pickup pipe a while ago and found some plastic parts there, but could never figure out where they came from, until now!

Will be getting a new dipstick as soon as possible, hopefully it will finally fix this issue that has been bothering me for two years now...

So make sure to check your dipstick if you haven't already done so! And thanks to @ch1z64 for mentioning the dipstick!


IMG 2699

Dipstick parts in the sump
IMG 2390
 
Same issue here,
its intermittent and some tines only happens once other times happens like the video several times.

I will check the dip stick tomorrow so far it sounds like there are a vast number of possible causes:

1) Dip Stick
2) PCV Valve
3) MAF Sensor
4) Vacuum Leak
5) Injectors
6) Air Filter
7) Throttle Body

Some of these are easier than others so I'll start with the DipStick and Air filter.
 
Last edited:
My dipstick isnt great. The o seal has come loose and little bit of plastic isnt there. I dont have this problem though
 
  • Like
Reactions: garethrees
That looks like a vacuum leak mine is dropping all the way down to idle and going up to around 1300 which is making me think it's something to do with the throttle body or idle control valve. It's going in today to be looked at so I'll keep you all posted
 
  • Like
Reactions: S. and garethrees
Thanks @R222cet for the update, look forward to finding out the results.

I looked at my dipstick and it's broken: IMG 20170512 094156
Bit worried where the plastic bits have gone.. will replace just in case.
 
garethrees said:
Thanks @R222cet for the update, look forward to finding out the results.

I looked at my dipstick and it's broken: View attachment 125389
Bit worried where the plastic bits have gone.. will replace just in case.
Click to expand...

if you happen to find a place reasonable for a new dipstick will you post please cheers
 
It does soubd like a horrible trial. At least you know all parts have been changed
 
I havent seen that one from psi. Only the £50 one... which is what ill be getting as i want black haha
 
  • Like
Reactions: HHS3
HHS3 said:
The PN for the revised OEM dipstick is 06F 115 611 F, you can get it from the parts request on here or mjr901 on facebook, should be between £10 & £20.

If you fancy wasting some money then PSI do a nice aluminium one for £30: http://www.psituning.com/product.php/22742/aluminium_dipstick___2_0_tsi
Click to expand...

Right lads you can buy straight from Audi for£11.40 i would advise you do as it has a 2yr warrenty with it as just off phone to Aberdeen parts getting my new one ordered .will post pics off it once i get ut Tuesday plus mentioned the problem to them and will see if they will look into the dipsticks .
 
  • Like
Reactions: garethrees
ch1z64 said:
Right lads you can buy straight from Audi for£11.40 i would advise you do as it has a 2yr warrenty with it as just off phone to Aberdeen parts getting my new one ordered .will post pics off it once i get ut Tuesday plus mentioned the problem to them and will see if they will look into the dipsticks .
Click to expand...

Sounds good mate.

It's only the older orange dipsticks that are faulty, the revised ones are yellow 06F 115 611 F.
 
Just been in and they've told me an intake pipe was lose they re attached it but on the way home it's still doing it
 
Replaced the dipstick today, no difference whatsoever. Did a few test drives in various conditions and tried to provoke the issue as much as possible. Releasing the throttle and pressing in the clutch while on boost I managed to stall the car a few times when revs dropped way below idle. Doing the same off boost only gives the rev hang around 1200 rpm. After a second or two the revs stabilize to a smooth idle around 800 rpm. So my issue seems to be a bit different to the usual rev hunting shown in the video above.

As the issue seems to be somewhat boost related I tried switching back to the oem rev G diverter valve instead of the dv+. Again no difference in the idle behavior, but noticed the car boosted way harder with the rev G valve fitted! Really surprised as the dv+ is supposed to be the best dv upgrade available...

 
That's abit similar to mine how do I post a video ? It's lumpy on idle and it revs on its own pretty must 99% of the time when the car is warm and the weather is warm.

Would throttle body be covered under warrenty ?
 
Just click the media button next to the smiley and paste your video url in there :)

Did the same test today with an A4 1.8 TFSI, noticed some rev hang at 1200 rpm before dropping to idle, so that might actually be normal on these cars. Never dropped below idle speed however.
Will try to diagnose the fuel pressure sensors next as I've read they can cause similar problems, N80 valve is another part on the list although that should throw an EVAP fault code...

Yes throttle body (or whatever part causing the issue) should be covered under warranty. The fault code you're getting suggests either throttle body or a vacuum leak...

If only I would get a fault code... This is probably the only time I'm actually hoping for it :O
 
You must log in or register to reply here.

Similar threads

Alfieaudi
Car revving itself
Replies
5
Views
2K
ch1z64
ch1z64
Alfieaudi
  • Ask a Question
Car revving itself
Replies
1
Views
810
S3AMJ
S3AMJ
alwaysconfusedaf
Car is revving itself
Replies
21
Views
4K
Troubs12
T
A
Car revving itself on idle ?
Replies
21
Views
39K
Raheem
R
M
S3 2.0 tfsi revving at idle on its own? not pcv changed it already
Replies
6
Views
2K
S38P--Joe
S
Top
Back