Fluctuating revs on idle s3

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AMARZSG

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Hi new to the forum have only owned the car for about a month(audi s3 8p 2008)the car has a full audi history and only 50k on it.But have recently got a problem that on idle the car some times drops revs to like 600 and then goes up to 2000rpm itself I have had it diagnosed by someone and they have said it could be the charcoal canister is this correct, because I don't want to end up changing everything. He also said a few other things like map sensor but it was misfiring on cylinders 3 and 4 but he said it's due to it running lean hence the blocked charcoal canister and said it has not come back as the coil pack issues.
I would really appreciate a bit of advice as to what it could be thanks!!
 
erratic idle can be PCV valve. Try and remove your oil cap with the car idling, if it is sucked on tight it could be PCV.
 
the diagnostics was throwing a lot of error codes up so was confused as to what it was, revs are very erratic at the moment as mentioned but will give the oil cap a go and see what happens. have done a lot of searches and as mentioned it could be the pcv any ideas on price guide and are there 2 of them?
also is it easy to replace yourself?
thanks
 
Last edited:
AMARZSG said:
the diagnostics was throwing a lot of error codes up so was confused as to what it was, revs are very erratic at the moment as mentioned but will give the oil cap a go and see what happens. have done a lot of searches and as mentioned it could be the pcv any ideas on price guide and are there 2 of them?
Click to expand...

Hi
PCV (positive crankcase ventilation valve) seems the most likely cause for hunting.
Part No: 7
AUDI A3/S3/SPORTBACK/QU. [A3] (EUROPE) 1998: ENGINE: 13320. THROTTLE VALVE CONTROL ELEMENT; VACUUM SYSTEM; INTAKE SYSTEM


You could also check for air leaks around the manifold as this will affect the mixture and the ECU will fight to correct the issue. This in turn will bring up several error codes.
If you have the error codes list them as this will give us a clue to the issue.

Cheers


Marty:blackrs4:
 
Last edited:
Pcv valve mate just done mine think if I'm rite it was £38 from tps takes 5mins to change.
 
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martynash said:
Hi

Check for air leaks around the manifold as this will affect the mixture and the ECU will fight to correct the issue. This in turn will bring up several error codes.
If you have the error codes list them as this will give us a clue to the issue.

Cheers


Marty:blackrs4:
Click to expand...

don't have the codes to hand as the garage done the diagnostics but it threw up air/leak, idle control valve and think the charcoal canister or something like that so very confused as to what it is and don't want to do a process of elimination could end up costly. he also took the engine cover of to look for leaks but didn't find any.
 
AMARZSG said:
is there 2 mate one ontop of the engine and one inline(piping)somewhere?
Click to expand...

ImageUploadedByTapatalk1407594725072193thats it pal
 
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No probs, just squeeze the ends of the pipe to remove them thens it's about 5 t25 screws to take it off. Really easy to do, there's a gasket with it as well it's £15 little rubber one. Upto u if u change it or not.
 
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thanks mate just a quick one tho have had a look at it and as certain pictures I have seen they look clogged up mine seems clear no sludge etc coming out but presume it is the problem tho thanks!!!
S3 AEX said:
No probs, just squeeze the ends of the pipe to remove them thens it's about 5 t25 screws to take it off. Really easy to do, there's a gasket with it as well it's £15 little rubber one. Upto u if u change it or not.
Click to expand...
 
It's not the clogging that causes it really it's the diaphragm that splits in the circular bit.
 
ohh fare enough was a bit confused but with the help of you and the other lads think we have pinpointed the problem, so Monday morning I will get he pcv and replace it hopefully it does the job and back on the road.
Would I have to get the ecu reset after fitting this presume the error codes will still show?
 
No it'll be fine straight away but best to clear the codes.
 
martynash said:
Hi
PCV (positive crankcase ventilation valve) seems the most likely cause for hunting.
Part No: 7
AUDI A3/S3/SPORTBACK/QU. [A3] (EUROPE) 1998: ENGINE: 13320. THROTTLE VALVE CONTROL ELEMENT; VACUUM SYSTEM; INTAKE SYSTEM


You could also check for air leaks around the manifold as this will affect the mixture and the ECU will fight to correct the issue. This in turn will bring up several error codes.
If you have the error codes list them as this will give us a clue to the issue.

Cheers


Marty:blackrs4:
Click to expand...

I think the diagram you linked is for the 8L not the 8P.
 
Bought the pcv and gasket from Audi Rayleigh last week for £55. Very easy to fit.
 
martynash said:
*8L 8P is the body style not engine code*.
He didn't specify engine code but the same component as in diagram either way
Marty:blackrs4:
Click to expand...

I am aware 8P is not an engine code. He said his car was 2008. That diagram says 1998, and it certainly looks nothing like my 8P engine. So it could have been confusing that is all.
 
A very Big Thank you to all the help and advice from you guys, would have ended up changing numerous parts before pin pointing the valve was the problem.
Got the pcv valve and gasket from tps this morning at a cost of £55 a reasonable price to be honest.
Fitted the valve after work took only about 10-15 mins to change but me being a bit of perfectionist cleaned the whole engine bay while the cover was of, the cover is very tricky to take off and a nightmare to put back on that was the longest part of the Job lol
After that taking it for a drive no issues very pleased that it was only a minor issue with the car and have found the car running smoother also feels like the car is faster throughout the rev range. Of to the garage in the morning to clear any error codes.
And once again very grateful for the advice have saved me a lot of time and money!!!!
 
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Fantastic news!!!!! Thats what I love about ASN passion to help others

Glad we got you sorted out!!!!! :kiss:
 
Glad it's sorted mate, should blobbed abit of grease on the pins the engine cover goes on just makes it a little easier to remove next time. Or get a CAI and leave it off
 
Last edited:
Hi All...

Sorry to bring up an "Old" thread, but I thought it would best to have all the info in one place, and also save creating more...

So I have the above issue, and I am happy that it is the all too common PCV issue (Oil cap is being held down like a vacuum etc...) So firstly thanks for all the info on here, it clearly helps...

What I was wondering was instead of buying the original plastic part from Audi, could I simply replace it with the Forge PCV delete part from the likes of Awesome GTI instead? I know they advise the catch can as well, but is it necessary!?

I'd much rather shell out an extra £20 or so for a better apart rather than the one that keeps clearly failing on these engines...

Many Thanks to you all...
 
Looks ok but don’t think it’s genuine. You’re not going to order from the US are you (unless you’re there!).

Use the parts request at the top of the page or if you have Facebook Messenger contact Mike on Mjr901, he’s the VAG Main Dealer man.
 
I'm not in the US sadly, so many pcv types on Ali express but I assume they are all imitation.
 
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