misfire issues..... still!!!! aaagggghhhhh!

[adsisbest]

Hi, haven't been on here for a while but hoping you guys and your masses of experience can help me before i end up driving my car off the nearest cliff!!!

Had my 1999 S3 for a few months now, and what originally started out as a small intermitent misfire under load in 4th, 5th and 6th gears has now developed into a major misfire in all gears and i cannot for the life of me get it sorted!!!

To cut a very long story short, i'm very aware of the usual misfire issues and typical fixes to resolve it, but even now after i've...

replaced recirculation valve, fitted 4 brand new coilpacks, new set of top quality spark plugs, new genuine Bosch MAF sensor, and replaced most of the major turbo/breather pipes including some of the smaller ones with forge pipes, still no joy, if anything its getting worse!!!!!

Main problem is, from the word go the car is dropping no fault codes and i've never had any warning lights on the dash. (small lie, had one fault code for coolant temp sensor, now also replaced with new genuine audi part!)

Car now misfires in pretty much every gear as soon as i hit 3000rpm and is really starting to get me down as i still as yet haven't been able to enjoy the car to its full potential!

Please guys, i know lots of people ask about misfire issues but i really have run out of ideas and need your help.

Many thanks, adam

[adsisbest]

update from original post:-

Went up to my local Audi Dealership earlier today to buy a replacement clip for coolant temp sensor as old was was shot and asked if i could get some advice from one of the mechanics.
Parts guy asked what problem was and his answer, as is every time i ask for some 'expert' advice, was, pay £57 and they'd diagnose problem. Explained that i've had diagnosis done twice already on decent bosch diagnostic equiptment and car shows no fault codes therefore not prepared to fork out to be told same thing again.
He then said that their equiptment will sometimes find codes that others won't because it does a much deeper search. Is this true??? or is this guy just full of s**t, because to be honest, the impression i get from the morons in that place everytime is, unless you walk in with a blank chequebook, they couldn't give a toss what your problem is.
Said i would concider it and get back to him.

My gut feeling, after replacing so much already and reading through pages and pages of forum threads, is it has to be the 'ignition amplifier' or 'ignition module' as some people have referred to it. Trouble is, when i mentioned the possibilty to Mr helpful from Audi Plymouth said he "wasn't sure, would have to plug it in and test it first" yet again! (seems they no longer have the ability to give general advice without first plugging it in to something!!!).
Then after spending the best part of 20mins looking up my reg details on his computer he reckoned there were three of the buggers on my car starting from £107 upwards each but couldn't tell me where they were located on the car (probably need a machine to tell him that!).
Went to GSF to ask about ignition amplifier... nice guys, couldn't be more helpful but needed part numbers as not databased on their systems. Said get us part numbers and even if we don't stock them we'll find someone who will.
Called Audi, asked for part numbers so i could cross reference what i would be removing from the car and matey says he'd have to look them up, will call me back in 15-20mins...... 3 hours ago!!!!! Muppet!!

Therefore, after that rather long-winded rant (sorry about that just needed to get it out!) i have a couple of questions:

Is the general feeling that it is the ignition amplifier?

If so, where can it be found on a 1999 S3, APY engine code? And are there three of them? Does anyone know where i could find the part numbers without going back to the nob in my local Audi garage?

If not then looking at my original thread, any ideas what it could be???

I'm seriously lost with this now, please help!!!

[adsisbest]

now know its not the ignition amplifier as apparently my S3 doesn't have one being APY engine type, so don't understand why the guy at audi reckoned i had 3 of them!!???

As i previously asked, can anyone confirm if the Audi diagnostic equipment can pick up faults that others can't? if so may need to bite the bullet and pay for them to test it after all, as much as it will pain me to do so.

Also, anyone else with previous experiences similar to mine have any ideas what i could take a look at next without splashing out loads more cash???

i know i've asked before but no-one seems to have any ideas? do people still use this forum or have i upset someone???? lol

cheers again, adam

[zollaf]

the coil packs are driven directly by the ecu, so no ignition amp. a misfire can be the engine loosing a spark, or fuel, or lack of compression. the map sensor can also be responsible. you need a diagnostic computer to check live data of all sensors to see if anything isnt right. then an oscilloscope can be used to check the pulses to the injectors and coils. this needs to be carried out when the misfire actually occurs. if no anomalies can be found, then it could be the actual injector, or a sticking or burnt valve. basically you need someone with diagnostic gear who can use it to pin point the fault. all too often you hear 'no fault codes, no problem', but there is a lot more to diagnostics than a fault code. i dont know where in the country you are, but if you are near nottingham then a chat with crasher at C&R would be a step in the right direction. it may not be cheap since diagnostics arnt, but at least your car would work.

[kite]

What zollaf said, and also that would stop you throwing parts at it.....

[adsisbest]

fair one guys, at the end of the day no one enjoys throwing money at a problem with no light at the end of the tunnel. trouble is, i'd originally hoped that having had the car diagnosed twice over the course of a few months would have picked something obvious up but it didn't, and i didn't fancy handing my car over to audi and saying fix it cos i may as well give them my blank chequebook pre signed so they could rape my bank account! either way, its gonna cost me! just wondered if there was any truth to the fact that they'd be able to identify faults that maybe other garages may not.

I'm a man that likes to be able to sort his car out himself without paying a garage to do the work as i'm sure most of you guys are, but i have to say, this ones got me beat!!!

in reply to zollaf, i assumed myself that its best to identify a problem while its occuring but unless its on a rolling road, how would they do this, as the misfire/fueling problem only really kicks in on boost at @ 3000rpm. i've noticed recently that i can bypass the issue by accelerating slowly past 3000rpm in the same gear, and once past about 3500-4000rpm if i then floor it, the car goes like s**t off a shovel. otherwise accelerating and changing gear normally, as soon as it comes on boost the car jumps all over the place! sound familliar to anyone???

p.s. i'm in plymouth so as much as i'd love to pop up and see crasher (as he does seem to be the man in the know on here) its a bit far to travel. bugger really! Although in saying that, at this rate, i'm sure i'll still have the same problem by the time edition 38 comes around again and thats in the same neck of the woods???

cheers for your feedback tho guys, much apreciated