S3 210bhp very flat until 5k rpm

[Dex]

hey I'm new to this forum, and s3's as this is my first but it seems to have a problem
If your poodling around town it drives fine, but once you open it up it seems very flat until about 4.5-5k rpm and then goes like f**k, it also backfires at 3000rpm if your playing with the throttle
It has a decat pipe
I have replaced all vacuum hoses with silicone
I have

 

[Dex]

I have bought I genuine bosche maf that was tested and put that on but it has made little to no difference,
Any help or pointers would be greatly appreciated

 

[superkarl]

VCDS. Your best chance of diagnosing a problem.

Without that it's all guess work and could be a hundred different things

 

[Dex]

I see, I will have to try and find someone in my area with it and who knows how to use it, I have it on my laptop but haven't got the cable or know how to use it

 

[daz-20vt]

buy the cable and get a mate to go along with you.
the guys here will tell you what to log for i am sure!
if i knew id help

 

[Dex]

Ok il have a look, do you know if the flebay ones work? As I don't want to shell out too much on a cable for if I don't like the car once done lol

 

[<tuffty/>]

http://www.audi-sport.net/xf/thread...lp-please-read-before-posting-updated.168407/

<tuffty/>

 

[Dex]

S3 year 2000 apy engine 210bhp, only mods are decat and panel filter

 

[derek84]

Mine did this once it got to 5k ish would feel it but mine was because it had a Chinese turbo and it used to surge it's nuts off

 

[jojo]

I'm guessing the wiring harness for the coilpacks.

 

[Dex]

Mine did this once it got to 5k ish would feel it but mine was because it had a Chinese turbo and it used to surge it's nuts off

That may be the case with this as I have only owned it for 3 weeks, I hope not though. Is there any way I could tell?

 

[Dex]

I have noticed that part of the harness is all taped up as I guessed it had been replaced, is it worth pulling all the tape off and looking? Hopefully they aren't just twisted and taped, do the wires break or burn out? Just so I know what I'm looking for

I'm guessing the wiring harness for the coilpacks.

 

[jojo]

I have noticed that part of the harness is all taped up as I guessed it had been replaced, is it worth pulling all the tape off and looking? Hopefully they aren't just twisted and taped, do the wires break or burn out? Just so I know what I'm looking for

Common issue with the wiring harness is, especially with cars of your age, the plastic goes brittle and starts to crack, leaving the wires exposed, so the missfire is like the wires shorting out.

 

[Dex]

(Jojo)
Oh right, if I get a chance tomorrow il look into that as if there are any bad ones I will replace them

 

[Dex]

Common issue with the wiring harness is, especially with cars of your age, the plastic goes brittle and starts to crack, leaving the wires exposed, so the missfire is like the wires shorting out.

I have just been out and removed the insulation tape covering the wires, this is what I found, the taped single wires worried me but they were all fine apart from the one missing some of its casing, I have circled it in the pic, but should I have all these joins in the harness? Or is this not a problem?

 

[Dex]

 

[Dex]

Also I have noticed my coil packs push in and 2 of them have bam written on, but there are 4 bolt holes around each coil and my engine is a APY

 

[jojo]

Also I have noticed my coil packs push in and 2 of them have bam written on, but there are 4 bolt holes around each coil and my engine is a APY

Hi, can't answer your first question, as I've never had this problem on my car.

Regarding the coilpacks, APY should have bolt down coilpacks, but later cars, AMK&BAM, have push down coipacks. Nothing wrong with running these versions of the coilpacks, so nothing to worry about.

 

[jojo]

One other thing you might want to look at is the connector for the MAF sensor, pull it off and inspect the plug and pins.

 

[Dex]

One other thing you might want to look at is the connector for the MAF sensor, pull it off and inspect the plug and pins.

I inspected that while I was out there but they were fine, well until they join into the loom anyway

 

[Dex]

Does anyone know if that harness looks ok ? Or should I replace the wires that are full of joins and that bare one?

 

[Tom93]

Personally i think you should replace the lot. And mis matched coils are a sign that someone knew it had coilpack issues and just replaced one or two not just whole new set in there.

 

[Dex]

That is what I was thinking, il get out there tomorrow and sort the bodged wiring, if that doesn't cure it il get new plugs and coils

 

[Tom93]

You can get wiring harness from Awesome, about 35 quid just cut and solder one wire at a time, real easy, just make sure the wires are the same length when you cut so they go back in the conduit neatly. Coils you could just buy 2.0tfsi ones, cheaper than new 1.8t ones, and then plugs get the bk7re....

Also on the coil subject it looks like all yours have been changed because they all look like push fit ones to me, and your rocker cover suggest you should have bolt down ones, hmm.

 

[Dex]

Ok thanks mate, il get on with that

 

[Samuealle]

Ok thanks mate, il get on with that

Buy some heat shrink too. Don't use electrical tape. Its **** in every way.

 

[oldcar]

I thought he said :back fired" not misfire....check for your NGK plus make sure its geniue-with stamps on the nuts and so on....

 

[Dex]

There isn't a misfire, just a back fire and a large flat spot

I thought he said :back fired" not misfire....check for your NGK plus make sure its geniue-with stamps on the nuts and so on....

 

[Dex]

Bit of an update
I've Spent the last 2 nights cutting dodgy looking connections and replacing wires in the wiring harness, I have just got it all done and back together, with new ngk platinum plugs
I just took it for a test spin and it is better, not so flat but still very boring. I gapped the plugs to 0.8, replaced a few more pipes that looked cracked etc
I think a set of red r8 coils are the next thing as mine are miss matched and look fairly old.
My old spark plugs were bosche and the firing end was white, and wouldn't 'wipe' off, ngk website says it has deposits, was this because of crappy plugs or something wrong with the car?

 

[jojo]

White usually means running lean. Could your fuel pump be a bit weak?

 

[Tom93]

TFSI coils would more than suffice

Also fuel filter?

 

[Dex]

But red r8 ones look cool too lol
The boy said it had been serviced, but after seeing the plugs I was going to give it a full service next week

TFSI coils would more than suffice

Also fuel filter?

 

[Dex]

White usually means running lean. Could your fuel pump be a bit weak?

That is always a possibility, how could you test it though? Or is there a way to see if it's just a normal a3 one? Nothing would surprise me with how this car seems to have been treated

 

[jojo]

That is always a possibility, how could you test it though? Or is there a way to see if it's just a normal a3 one? Nothing would surprise me with how this car seems to have been treated

Doubt it'd be an A3 one, the S3 one is a twin pickup, A3 one won't work... Guess you could need to log it to see if the fueling is upto scratch?

 

[oldcar]

Bit of an update
I've Spent the last 2 nights cutting dodgy looking connections and replacing wires in the wiring harness, I have just got it all done and back together, with new ngk platinum plugs
I just took it for a test spin and it is better, not so flat but still very boring. I gapped the plugs to 0.8, replaced a few more pipes that looked cracked etc
I think a set of red r8 coils are the next thing as mine are miss matched and look fairly old.
My old spark plugs were bosche and the firing end was white, and wouldn't 'wipe' off, ngk website says it has deposits, was this because of crappy plugs or something wrong with the car?

mine is gray-light brown......air fuel ratio is 12.5 to 1 by revo .

 

[Dex]

mine is gray-light brown......air fuel ratio is 12.5 to 1 by revo .

im not aware if mine has a remap mate so I have no clue what ratio il be running, I keep trying to upload a pic of the plugs but it won't let me for some reason