P.I.T.A Missfire Problem

[Audi Parts Guru]

OK, so my S2 Avant has a rather annoying intermittent missfire on number 2 cylinder. Now, I've done the following and I still have this intermittent missfire

1, swapped the plugs around, no difference
2, fitted a new coil to number 2 cylinder, no difference
3, swapped POS units, no difference, missfire is still on 2
4, fitted a fully refurbished set of injectors, no difference

Having said that, when I apply some pressure to the POS backing plate, the missfire does appear to go away

Any ideas folks???

[Tonks4x4]

Do a compression test.

[Audi Parts Guru]

Do a compression test.

It's definitely electrical

[Tonks4x4]

Pull each injector plug off while it's running and see if you can round it down to just one cyliner.

Is it lumpier when it's warm idle than when it's cold idle?

[A80Avant]

as i wrote to your other thread i have a pos unit if you want to test/buy.

[Audi Parts Guru]

Pull each injector plug off while it's running and see if you can round it down to just one cyliner.

Is it lumpier when it's warm idle than when it's cold idle?

It's definitely number 2 cylinder

[Audi Parts Guru]

as i wrote to your other thread i have a pos unit if you want to test/buy.

Many thanks, I may well take you up on that offer, I just need to be a bit more confident that it is a faulty POS unit as I swapped the POS leads around and the missfire was still on number 2 cylinder, indicating that the fault lies elsewhere

[Tonks4x4]

And have you swapped the ignition coils around with number 2?

Same as you say if you have swapped the POS over and that was at fault you would expect it to change cylinder.

[Audi Parts Guru]

And have you swapped the ignition coils around with number 2?

Same as you say if you have swapped the POS over and that was at fault you would expect it to change cylinder.

Read my first post

[Tonks4x4]

Then surely you have covered all electrical???

I take it if you crank it over with the coilpack cover off and all the plugs in the end on top of the engine they are all giving a good spark?

On from that it can only be fuel delivery through injector 2

or

Compression?

[Audi Parts Guru]

Then surely you have covered all electrical???

I take it if you crank it over with the coilpack cover off and all the plugs in the end on top of the engine they are all giving a good spark?

On from that it can only be fuel delivery through injector 2

or

Compression?

It's intermittent, so it can be ok for a while and then suddenly start to missfire. I've also fitted a fully refurbished set of injectors that are perfect (I know, i tested them ;o))

I'm sure it's electrical, and I think it has something to do with the loom around the POS backing plate as the missfire goes away when I apply some pressure to it

[Audi Parts Guru]

As for compression, well that would surely be there all the time.

My missfire comes and goes all the time. It could be fine for one day, then missfire the next

[mcandmar]

If you have ruled out the POS units i would suspect a broken wire or dodgy connector. Wiggle all the connectors and wiring loom and see if you can locate the problem.

Just dont do it on a car with HT leads and a miss fire. ...dont ask

[Audi Parts Guru]

If you have ruled out the POS units i would suspect a broken wire or dodgy connector. Wiggle all the connectors and wiring loom and see if you can locate the problem.

Just dont do it on a car with HT leads and a miss fire. ...dont ask

It's an ABY, so I don't really have HT leads

[Evilgoat76]

If you have ruled out the POS units i would suspect a broken wire or dodgy connector. Wiggle all the connectors and wiring loom and see if you can locate the problem.

Just dont do it on a car with HT leads and a miss fire. ...dont ask

Hurts doesnt it?