1.8T running fault.. Getting REALLY annoying now!

[bristolbaron]

I've got a running issue with my 1.8T A3.

It idles fine after having a coilpack replaced, and pulls very well until around 4-5.5K where it judders. I thought I had it narrowed down to MAF or N75 valve, however having checked the MAF by unplugging it, there was no difference, so I replaced the N75.

It's still exactly the same - pulls to redline in first and second and then in third will get to 4-5.5K and the judder is back..

I'm guessing there's either a split hose somewhere which I have missed or perhaps I need another coilpack? I wouldn;t have thought it was that though as idle is perfect.

Any other ideas???

Cheers

Baz

 

[Alex C]

could be coilpack causing misfire when engine is under increased load? so you wouldnt notice it when idleing or low gears...

 

[colicabcadam]

normally when one coil goes, it puts pressure on the others, so you have 1 good coil pack and 3 weaker ones.... now the 3 weaker ones are putting pressure on the newer one.....

change the other 3 asap

 

[bristolbaron]

Yeah Im thinking this is going to be the case.. was advised just to replace the dodgy coil, but looks like im gonna have to shell out for the lot.

Other advise has been to double check hoses including intercooler outlet pipe as main culprit..

 

[Alex C]

Have you checked if audi will replace them free of charge??

http://www.audi-sport.net/vb/a3-s3-forum-8l-chassis/113780-audi-recall-all-petrol-engines.html

 

[S3KO4]

You say it made no difference with unpluged maf! there must an issue with the maf then I would have thought. I have replaced one coil since last year I don't think it has affected the rest, why would it? if I am convinced then I might change mine as well.

 

[s3dave]

Are you sure its the engine and not the car? 3rd gear 4-5k revs you will be knocking on a bit, maybe wheel balancing....

 

[Sandip]

Have you checked the plugs? make sure they are gapped correctly

 

[bristolbaron]

So today I fitted the other 3 coilpacks as that was the most common suggestion..

Also checked again for boost leaks, especially around the pancake pipes. I'm pretty sure there's no hoses loose, and cant see or feel any splits.

I have noticed a slight 'dump valve' noise on let off when the window is down.. the car has standard airbox so should I hear this? Again would prob point towards a leak but where from!?

I really don't want to pay out for anything else that's not going to solve the problem - fuel filter, coilpacks & N75 have set me back enough so far..

I guess only option now is to scan it again..

 

[bristolbaron]

I had a Bailey DV30 and K&N filter sat at home so thought i'd fit them to see if it helps with breathing. Still holding back at around 5k in 3/4/5th but does seem a bit better..

 

[Sandip]

Have you checked your plugs?

 

[beachbuggy]

Sounds to me like the car is under fuelling when on boost. Either the FPR is faulty or you have a split in the pipe that goes to the FPR and thus when on boost the fuel pressure isn't rising to meet the increase in PSI.

The engine is really only put under load in 3rd + gears and so 1st and 2nd the problem wont really be an issue.

Check the pipe work to the FPR to see if it's got any splits.

 

[JamJay]

Have you scanned the car (or did I miss that)? If there car is running too hot i.e. the EGT's are too high then the car will dump fuel to cool it and cause you a judder. That'll be easy to spot with a scan though, the car will throw a fault from the EGT sensor.

Check the PCV pipes under the inlet manifold, ofter over looked but often the cause of many hesitation or judder.

 

[bristolbaron]

AND THE WINNER IS....

sandip

With the correct answer of spark plugs!! Finally, the car's running great and now has a whole host of items replaced which didn't need doing!

Only fault that came up with scanning was MAF - however that would've been from when it was unplugged.

Cheers all for suggestions..

 

[DenCar]

Glad you got it sorted.

Well done sandip, by the way what time did you get to Awsome last saturday? I arrived at 9 and left at 10:15.

DC

 

[s3dave]

Great, interesting about the plugs were they old? or not gapped correctly?

 

[bristolbaron]

plugs were old.. will take a pic if i get chance, but tips had worn..

 

[s30000t]

yeah mine has the same issue i think how much are the plugs?

 

[Sandip]

Glad you got it sorted.

Well done sandip, by the way what time did you get to Awsome last saturday? I arrived at 9 and left at 10:15.

DC

I got there a bit late lol around 11:30ish i think

 

[Sandip]

yeah mine has the same issue i think how much are the plugs?

BKR6e's are £8 - £12 for a set. Ideally change these every 6-8k along with the oil