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Hello S3 wizards. I am an avid reader of this forum and use it quite a bit for ideas/fault finding etc. I try not to ask to many questions as the answers can usually be found with a bit of patience...however, some opinion on this would be helpful.
Car is a stage 1 mapped 2003 S3 8L. The mapping was done by the previous owner at atlas remapping (if anyone has heard of them?). Any way, a month after i bought this car it started to hesitate and misfire whilst driving, mpg wen through the floor (down to 10mpg on last run). I think its grosely overfuelling but rather than chuck the usual new maf, coils etc i have been trying to at least have an engineered guess of what the problem is.
Now i think i might have a wiring or control lambda fault, here is my resoning......from cold the car seems to behave itsself, although a bit of a rough initial start (leaky injectors maybe). any way all the maf and injector times look ok whilst warming up. When it gets to a certain point the lambda control seems to go wild (live control value jumping all over the place), it then seems to stop altogether (see pic) the third digit in block 030 stays at zero.
Does anyone have any opinions, do you think im on the right lines. Im a bit concerned that the second lambda stays at mostly 100. (the htr does flick to zero every now and then) but i didnt think this had any control over fuelling?
I am getting zero fault codes (although i have had multiple misfires detected when ive taken it on a test drive and tried to boot it and get some readings). Also, disconnecting maf has no affect so I think i have ruled that out.
Im very close to buying a new lambda for the control (pre cat side). just dont want to throw cash at it and replace parts until its fixed (I'm not an audi engineer....).
I've done a through check of boost and vac lines, cant find anything obviouse, i was thinking FPR but this now all happens at idle, or could a faulty FPR allow too much fuel pressure and effectively over fuel the engine?
Thanks in advance guys, I'm trying not to ask silly questions or get you to do the work for me, just a bit of guidance is what i'm after (before a take a sledge hammer to the damn thing lol)
Car is a stage 1 mapped 2003 S3 8L. The mapping was done by the previous owner at atlas remapping (if anyone has heard of them?). Any way, a month after i bought this car it started to hesitate and misfire whilst driving, mpg wen through the floor (down to 10mpg on last run). I think its grosely overfuelling but rather than chuck the usual new maf, coils etc i have been trying to at least have an engineered guess of what the problem is.
Now i think i might have a wiring or control lambda fault, here is my resoning......from cold the car seems to behave itsself, although a bit of a rough initial start (leaky injectors maybe). any way all the maf and injector times look ok whilst warming up. When it gets to a certain point the lambda control seems to go wild (live control value jumping all over the place), it then seems to stop altogether (see pic) the third digit in block 030 stays at zero.
Does anyone have any opinions, do you think im on the right lines. Im a bit concerned that the second lambda stays at mostly 100. (the htr does flick to zero every now and then) but i didnt think this had any control over fuelling?
I am getting zero fault codes (although i have had multiple misfires detected when ive taken it on a test drive and tried to boot it and get some readings). Also, disconnecting maf has no affect so I think i have ruled that out.
Im very close to buying a new lambda for the control (pre cat side). just dont want to throw cash at it and replace parts until its fixed (I'm not an audi engineer....).
I've done a through check of boost and vac lines, cant find anything obviouse, i was thinking FPR but this now all happens at idle, or could a faulty FPR allow too much fuel pressure and effectively over fuel the engine?
Thanks in advance guys, I'm trying not to ask silly questions or get you to do the work for me, just a bit of guidance is what i'm after (before a take a sledge hammer to the damn thing lol)
