Audi S3 Clutch / REV problem - HELP!

[jamiebrayley@yahoo.co.uk]

I have a problem and it seems to be a very common one. Basically when the car is on full boost when I go to change gear the revs rise suddenly (as much as 500rpm) before dropping. It only happens when on boost. I have done a search for this and have changed the clutch pedal position sensor and the DV valve (for a forge one). The problem still persists. There are no error codes when you plug the vag-com in. Any ideas?

Maf maybe?

Thanks

 

[nershen]

Sounds like your clutch is starting to slip. Mine started off doing the same thing and now it slips horribly when the car comes into boost.

 

[PorkyWill]

I have exactly the same problem with mine and it is a pain in the backside!!

Vagcom throws up a clutch swith error so I will be changing that but if that hasn't worked on yours then I'm stumped...oh and I have a new clutch in mine so it can't be that...it's also not really the symptoms of a slipping clutch I think you'll agree?

When I can spare the car it is going to The Phirm for a few days so Tim can drive it around and try and diagnose/solve the problem.

I'll post here when he has fixed it to let you know what it was, but I'm still unsure when this will be...

Will

 

[jcs356]

Sounds like a slipping clutch to me.

 

[PorkyWill]

It's not a slipping clutch I assure you. My Sachs clutch is as tight as anything and off boost there is no over revving at all. This only happens when you go to change gear so there's no slip through acceleration at all, just 500k over rev on gear change when you are on boost.

Will

 

[RussUK]

Don't all S3' do this??

 

[marms]

Sounds like it might possibly be the wastegate control valve?

I had similar revving (almost like a surge) when changing gear and changed the N75H for a N75J valve (I think that was the name of the part) and fixed the problem.

Before anyone says anything, that was on a previous Mk4 Golf GTi which I had mapped, Didn't happen before the map and never recorded any CEL.

 

[Starry]

i have posted on this before, its a pain in the ***. i have changed the clutch switch. but after fitting it i was told it was there to cut the cruise control when you push the clutch. anyway it never worked, i cleaned the throttle body which made no odds either. i am now going to try a n75 to see if this sorts it out as im fed up with looking like ive screwed up the gear change... HELP!!!!!!!!!!!!

 

[jamiekip]

I had this on my old S3.
Things to check:
1. MAF - can cause throttle to stay open and rev's to shoot up when changing gear.
2. Clutch pedal assembly switch - again causes revs to shoot up as it doesn't recognise the clutch is depressed quickly enough
3. Clutch master cylinder - again this gives the impression of a slipping clutch.

I'd check all of these cheaper options before changing the clutch (super expensive job to do this!) as I was diagnosed with a worn clutch and had it changed. Drove 2 mins from the dealer and knew instantly that the car was still doing exactly the same thing. I went straight back and demanded to see the old clutch - under there own admission it still had a 1/3 of it's life left... played war as if the clutch was fine did they not think there maybe another problem???? Anyway, they ended up doing the MAF, Master cylinder and clutch switch free of charge and this cured it.

This problem seems to be coming up a lot in this forum now.....

Good luck mate

 

[PorkyWill]

Interesting...

Mine also has a new MAF so I'd hope it won't be that.

The only error is the clutch switch but that doesn't seem to solve the problem...

It really is a pain the bum as if you get a nice stretch to really have a go in the car, it is jerky on gear change and over revs and makes you sound like you cannot drive!!!

Will

 

[jamiebrayley@yahoo.co.uk]

Thanks for the response guys. Its definately not a slipping clutch, and it only happens when on boost. I am guessing wastegate control valve then? If a MAF is faulty wont it show up on VAG-COM? And if it was faulty the car would run like **** wouldnt it?

 

[golf]

I had the same problem with my A4, and it turned out to be a faulty clutch switch. It's worth a try because the part is £11.01 from Audi, and it's pretty easy to fit.

Before when I used to change gears while in high RPM, the revs would climb, but now as soon as the clutch is pressed they drop. Alternatively it could be a sticking throttle body (I am also suffering from this )

 

[jamiebrayley@yahoo.co.uk]

I had the same problem with my A4, and it turned out to be a faulty clutch switch. It's worth a try because the part is £11.01 from Audi, and it's pretty easy to fit.

Before when I used to change gears while in high RPM, the revs would climb, but now as soon as the clutch is pressed they drop. Alternatively it could be a sticking throttle body (I am also suffering from this )

Hi, I have replaced the clutch pedal position sensor already, and the DV (in my first post). So starting to clutch at straws. It only happens when car is on full boost which to me indicates its turbo related - i.e. wastegate, rather than throttle body as the problem would happen on or off boost then as well?

 

[RussUK]

Hi, I have replaced the clutch pedal position sensor already, and the DV (in my first post). So starting to clutch at straws. It only happens when car is on full boost which to me indicates its turbo related - i.e. wastegate, rather than throttle body as the problem would happen on or off boost then as well?

Have you given any garage's a call? someone like APS might know.....

 

[golf]

Hi, I have replaced the clutch pedal position sensor already, and the DV (in my first post). So starting to clutch at straws. It only happens when car is on full boost which to me indicates its turbo related - i.e. wastegate, rather than throttle body as the problem would happen on or off boost then as well?

Sorry didn't read your first post properly. If you've changed the clutch switch already, then it could be the N75, the MAF or the throttle body sticking.

In my case after I changed the clutch switch the revs would drop as soon as the clutch was pressed but if I am flooring it and lift off the accelerator (without touching the clutch) the revs seem to stick, which indicates a sticking butterfly valve in the throttle body. Maybe you have the same kind of problem.

The N75 can be had cheaply enough and a used throttle body can be found on eBay for around £50.

 

[Pete20vTurbo]

Hi, sorry to barge into your thread (well whole forum in fact). Anyway, did you ever get this sorted at all? I've had the same problem in my car (Ibiza Cupra 1.8T 20v) since i've owned it (2+ yrs). I'm absolutely stumped as to what it can be. So far i've:

• Fitted a new DV
• Tried reversing the DV
• Throttle body alignment via Vag-Com
• Fitted several new clutch switches (with correct clearance)
• Firtted new MAF

As above it only happens when on boost and feels/sounds very much like either the clutch is disengauging very slowly or the the throttle body is closing very slowly. Gear changes are very much normal and very positive when of boost.

You guys mention it could be the clutch master cylinder, how would i go about checking this? I really am at a loss now, its enough to make me consider selling the car now.

 

[Starry]

changing my n75 valve to a J version has helped a lot but still not totaly cleared it up.

 

[Pete20vTurbo]

Ok, that sounds like the next step then. Was the N75J standard on any cars or am i going to have to go to the dealers?

 

[Starry]

go to vag parts mate.

 

[Starry]

also this valve will make your car boost a little higher and on some cars it will go into limp mode. its been fine on mine though

 

[Meza]

Have you tried adjusting the clearance on your clutch pedal switch?

The little peg on the switch pulls out on a ratchet and then I believe should push itself back in to the correct level when you press the pedal down. Try getting down there and pulling the peg out as far as it will go.

 

[Pete20vTurbo]

Have you tried adjusting the clearance on your clutch pedal switch?

The little peg on the switch pulls out on a ratchet and then I believe should push itself back in to the correct level when you press the pedal down. Try getting down there and pulling the peg out as far as it will go.

Yeah tried that mate, measured the clearance on a mates Cupra. Ours are different to yours, our switch has a thread around its body and you just screw it into a tapped hole in a bracket. (pretty **** really as the thread is plastic and strips out quite alot)

Tried a few other things today: Fitted a different throttle body and smoothed out my accel pedal movement by greasing the various joints on the throttle linkage as after watching the butterfly open and close i could see it was quite jerky. That done the car does feel alot better, its not overrunning half as much now when on lower boost/revs. But it does still do it further up the rev range every so often.

Not sure what to try next?

 

[Pete20vTurbo]

My car feels 90% better today after having a bit of a fiddle after comparing my throttle to my neigbours car.....



We discovered my throttle pedal movement was real stiff and jerky compared to his. We watched the butterfly in the throttlebody which was also jerky. So, gave the throttle pedal linkage some grease which smoothed out pedal movement and in turn smoothed out the throttle body action. This has helped the car out no end.

 

[jamiebrayley@yahoo.co.uk]

I am still experiencing the problems. I have now chnaged the DV, the N75, the clutch pedal position sensor and the MAF. I have spoken to my friend who is a mechanic and he reckons there could be an air leak in the system

 

[millwrx]

could be.i have a missfire fault at the mo and have been changing parts but still no good

 

[jcb]

why would the clutch pedal switch have anything to do with revs?
AFAIK it is not there to affect anything to do with the boost, fuelling or interfere with the MAP.

Check you Throttle cable (if you have one), I had a kink in the housing which would give it a slight delay in coming off the revs in WOT situations

check all your vaccum lines to the N75 and the Wastegate actuator and the recirc valve,

try lifting off a little earlier......

 

[simch]

I have a problem and it seems to be a very common one. Basically when the car is on full boost when I go to change gear the revs rise suddenly (as much as 500rpm) before dropping. It only happens when on boost. I have done a search for this and have changed the clutch pedal position sensor and the DV valve (for a forge one). The problem still persists. There are no error codes when you plug the vag-com in. Any ideas?

Maf maybe?

Thanks

Is your car remapped.......? If so this is pretty standard. Many mappers engineer this "trait" in to protect the turbos from compressor stall. You just have to get used to ait a bit, change your gearchanging method and come off the gas momentarily before you wish to change gear, and dont try to snatch at the gears, change gear more slowly. When my BT was done it was very bad, the map was rejigged a bit to reduce it and now with getting used to it, I hardly notice it.
But its not just on gearchanges, there is a consistent delay when coming off the gas, only a few milliseconds but noticeable.

 

[Pete20vTurbo]

Clutch pedal switch should cut fuel when the clutch is depressed, but if the switch is broken etc then the ECU dosnt know that your about to change gear. Not a mapping issue either as several people i know have mapped 1.8T's and they do not suffer the same problems.

Air leak is feasable as boost hoses turn into vaccum hoses when off throttle. Any leak would suck air in off throttle, possibly keeping the engine going.

If all is well a DBW 1.8T should feel no different to a throttle cable version. If you watch the throttle body as you press the accel you'll see absolutely no delay at all.

Worth checking all your hoses and clamps, if you cant see any leaks then nip up all your hose clamps.

 

[jamiebrayley@yahoo.co.uk]

Clutch pedal switch should cut fuel when the clutch is depressed, but if the switch is broken etc then the ECU dosnt know that your about to change gear. Not a mapping issue either as several people i know have mapped 1.8T's and they do not suffer the same problems.

Air leak is feasable as boost hoses turn into vaccum hoses when off throttle. Any leak would suck air in off throttle, possibly keeping the engine going.

If all is well a DBW 1.8T should feel no different to a throttle cable version. If you watch the throttle body as you press the accel you'll see absolutely no delay at all.

Worth checking all your hoses and clamps, if you cant see any leaks then nip up all your hose clamps.

Will give it ago Pete, see what happens. This seems like the most likely scenario at present.

 

[jcb]

Clutch pedal switch should cut fuel when the clutch is depressed, but if the switch is broken etc then the ECU dosnt know that your about to change gear. .

sounds like horsesh1t to me........
you wouldn;t be able to rev the car with the clutch dipped if that was the case.

no reason for this to be true

 

[simch]

Clutch pedal switch should cut fuel when the clutch is depressed, but if the switch is broken etc then the ECU dosnt know that your about to change gear. Not a mapping issue either as several people i know have mapped 1.8T's and they do not suffer the same problems.

Air leak is feasable as boost hoses turn into vaccum hoses when off throttle. Any leak would suck air in off throttle, possibly keeping the engine going.

If all is well a DBW 1.8T should feel no different to a throttle cable version. If you watch the throttle body as you press the accel you'll see absolutely no delay at all.

Worth checking all your hoses and clamps, if you cant see any leaks then nip up all your hose clamps.

Sorry fella, I dont think you really thought about what you wrote, or know what you are on about! The clutch switch does not cut the fuel when you dip the clutch or the car would stall! It would not allow blipping of the throttle on downshifts either........!! So you are plain wrong! My understanding is that its fitted to all DBW cars and is only there to liaise with the crusie control system when fitted.

You may be confusing it with the brake switch which does effectively close the throttle butterfly to idle when its depressed, hence you cannot successfully left foot brake in a DBW car.

As for you knowing "several people" with mapped 1.8Ts well fabulous. But how many are K04 turbos with custom maps......? Like I said this is common, I know at least one custom mapper who engineer this in to protect the K04 turbos from compressor stall situations.
My throttle cable k03sport turbo with custom map does not do it, but both my DBW K04 /IHI cars do, all done by the same mapper, both for the same reason. I asked for one to be tweaked to reduce the effect on the IHI, and it is soon something you get used to.

 

[Pete20vTurbo]

I'm sorry mate, but the clutch switch has alot to do with the car revving while shifting. Unplug yours, and after a day or 2 the car will rev like hell when shifting. FACT.

My neighbour is our local Custom Code and REVO dealer and has also built a 500-600bhp Ibiza from scratch which he races. And i'm sorry but mapping the car to rev when shifting is nonsence.

As for the cars i KNOW personally (ie friends) dont rev, they include...

Neihbours Race Ibiza - Custom Code
A 250bhp Lupo 1.8T - REVO Stage 2
A 252bhp Ibiza - Custom Code
A 249bhp Ibiza - Jabba Mapping
A 350bhp Golf - Jabba Mapping
A 240bhp Ibiza - REVO Stage 2
My 220bhp Ibiza - REVO Stage 1
My Car - APR

And pretty much everyone on SeatCupra.net, ukmkivs, clugti and VAG20V. with includes plenty of K04's, Garrtets and IHI's. And all manor of mapping, APR, REVO, Custom Code, Jabba, Star Performance, P-Torque, Bell Auto... the list goes on. All of the above tuners are active on the forums and not once have any of them stated those traits exist in their mapping. Not even when people post with revving issues. 9 times out of 10 the issue is resolved with the replacement of said clutch switch.

When i said the switch cuts fuel, i was generalizing. The switch infroms the ECU what your clutch is doing. Try it for yourself, but you may need to drive it for a few days before the problem starts. I'm actually going on experience here, when it comes to solving clutch switch problems.

If you feel that the mapping on a k04 needs to rev the car when shifting then maybe you need antilag and there must alot of wrongly mapped Ibiza's Golfs and Leons kicking around. Maybe its just an Audi thing....... even though the engines are near identical.

 

[simch]

So the clutch switch does not cut the fuel then......? So you were wrong then?

Glad we sorted that out.........

Like I say, with some maps this is common, as the maps engineer an element of "run on" when the throttle is released. It is not engineered to "rev up" the feeling of revving up on up shifts is that you have just dipped the clutch and reduced the engine load, so as the throttle is just a little bit open still the car revs up momentarily. Its just a lag on the throttle butterfly.
Better timing of changes or map adjustment will cure the revving up, the throttle pot can be made to react to the pedal in pretty much anyway you like when mapping them, so the lag can be dialled out too. I know of at least one generic type of map and one custom mapper that deliberately introdcue this trait to protect the turbos. So if he has one of these maps, (IF) then he is chasing his tail trying to find a problem that is not there. If he does not like it, then he can change or tweak his map! Then its done!
But the orginal poster has not responded as to whether his car is mapped or not, so we have no idea as to whether this is his problem or not anyway.

 

[Pete20vTurbo]

JBS map the car since sponsering him, but the car has been heavily modified well before that and been through many turbo setups and maps. My missus car (Not mapped, so that rules out mapping in that case) has also suffered the revving issue in the past, but again, the clutch switch was at fault. All i'm trying to get accross is the fact the switch is the 1st thing that should be checked as its less than £10 and prone to popping out of its bracket.

Either way i'd be interested to see how the OP solves his problem.

 

[simch]

I think his original post said he'd changed what he called the "clutch position sensor" already.

 

[Pete20vTurbo]

I think his original post said he'd changed what he called the "clutch position sensor" already.

Then personally i'd check the clearance on it. Reset the TB via Vagcom (or similar) then check for air leaks and hose clamps etc. IF the car is mapped then as you say, no harm in checking with the tuner. But if the car has developed the problem sometime after mapping than the map can't be at fault.

 

[jamiebrayley@yahoo.co.uk]

Then personally i'd check the clearance on it. Reset the TB via Vagcom (or similar) then check for air leaks and hose clamps etc. IF the car is mapped then as you say, no harm in checking with the tuner. But if the car has developed the problem sometime after mapping than the map can't be at fault.

The problem was there before mapping and has only gotton more accute after mapping, which I attribute to the fact that the car is running higher boost pressure. The vag com shows NO errors, which is why I am inclined to think its an air leak?

 

[simch]

Jamie, do you have a stock diaphram DV fitted or an aftermarket piston version?
What map do you run and any other mods..?

 

[jamiebrayley@yahoo.co.uk]

Jamie, do you have a stock diaphram DV fitted or an aftermarket piston version?
What map do you run and any other mods..?

I changed the standard DV to a forge item in the hope it would cure the problem, so its not that. And the problem existed before the car was chipped and has only worsened not the boost has been raised.

Thanks

 

[m1ndless]

I had similar problems, sucks for you.