Help - Misfire!

[DBP]

Hi all,

 

I noticed the other day that when it was cold the vRS was boost surging, but fine once warm. So as I was backing out today the car was very lumpy and struggled to get away in first. There would be no power then all of a sudden kick in. I thought this was due to the cold and once it warmed up a bit this effect edged off.

 

I went out later in the day and noticed this effect was still there, if not worse now. She was very lumpy to drive and was back firing like crazy. So I imagined it must be a build up of fuel so I tried burning it off by putting the boot down, and, whilst moving in the high RPMs this is fine. But soon as you go back to your stop starts, the effect comes back.

 

Later on in the day I went for lunch, I noticed if I drove it really gently in first and second it was "ok". I also noticed that this effect only really kicks in on first and second when I am giving it beans, otherwise its "fine".

 

I don't know what to think? Because its back firing and lumpy, I can only assume its over fuelling, but it doesn't smell of petrol/drinking fuel. But this lumpiness only happens when the turbo spools and the foot is down in the lower gears :/

 

Any ideas?

[DBP]

Also checked the oil and it still clean atm.

[pauldazzle]

Maybe Coil packs. Have you had them changed under the VAG replacement campaign?

[Liverpool-Lad]

Does sound ignition related!

[vrsmark]

Things to check first...take the plugs out and have a look at them,check the gap and if they're ok plop them back in!

Before you do this next bit get the car scanned to what cylinders it's misfiring on,make a note which cylinders...? Now swap the coilpacks around and drive the car...scan it again and see if the misfire has moved to another cylinder!

You could also do that with the plugs and injectors!

This will help you see which onjector,coilpack or plug is causing the problem!

[DBP]

That is what my next thoughts where, coil packs and sparks.

 

I've had the packs changed under recall already. TBH, when the pack went last time, it doesn't feel like that. And on tick over it doesn't struggle. Its literally trying to pull away in the 0-3,000 RPM band.

[DBP]

when its not raining it try and pull the plug on the packs and see what happens.

[Liverpool-Lad]

Any fault codes?

[kentphil1]

Breather pipes ok?, when was throttle body cleaned last?. As others have already said get a scan done as soon as is possible.

[marko pollo]

my breather pipe (top rocker cover) was split and it caused her to surge wen given the beans, also her tick over wasnt the best, the top breather pipe joins to the air intake and if it is letting in air it will make her run lean as it joins after the maf, this does cause surges in boost, might b worth a look..

[DBP]

Can't get my Vag-com working so I used the torque app. And it gave me P0117 which is the G62 engine temp sensor, which according to Ross wiki, can cause idle issues. and rough running whilst cold and I have noticed it struggling to hit 90'c

 

tried unplugging the coils, all of them caused rough running and the engine sits steady when on idle.

[pauldazzle]

CTS failure is pretty much standard on VAG 1.8t's so it's no surprise you've got a fault code for that.  Yes it can cause rough idle, & running problems as the ECU won't fuel correctly. N.B. Replace with a genuine VAG CTS only.

[DBP]

CTS failure is pretty much standard on VAG 1.8t's so it's no surprise you've got a fault code for that.  Yes it can cause rough idle, & running problems as the ECU won't fuel correctly. N.B. Replace with a genuine VAG CTS only.

 

Well they only cost £10 to replace, so nothing to loose by just swapping it anyways. Noticed it hasn't been happy since the junction pipe snapped.

[pauldazzle]

£10 for an aftermarket one, which rarely work properly. Real VAG CTS is usually at least twice the price.  Buy cheap buy twice

[marko pollo]

cts??

[DBP]

This is Febi

 

http://www.vwspares.co.uk/octaviaswitches.php

[pauldazzle]

cts??

Coolant temp sensor.

[marko pollo]

Coolant temp sensor.

i dont feel daft at all lol

thanks mate