Problem with the S3, strange.. Help would be great!

[jonnyc]

Hey all..

Ok, so collected the car (private sale) and drove home.. Half way back I had a CEL flash up for 5 seconds, it did this twice then went away.. Now a bit of a description as to whats happening..

The car fires up fairly quickly (a little longer than usual, but about 3 cranks) but it runs terrible, on idle it has a very heavy misfire.. It will rev up but again with a big misfire and lots of pops from the exhaust etc..

I have a CEL on the dash but the codes are all relating to coolant which as far as I know the engine hasn't overheated.. Plenty of water in the engine and oil level is fine

3 codes stored..

Rear heater core temp sensor (G154) Sporadic 001- Upper limit exceeded

Coolant temperature sensor at radiator outlet (G83) Sporadic 001- Upper limit exceeded

Coolant temperature sensor at engine outlet Sporadic 001- Upper limit exceeded

So this is where it gets interesting..

I pulled the coil packs and swapped them all with coil packs I know are working from another 2.0T FSI car.. No difference made what so ever..

So then I thought it must be the plugs..

They all came out looking clean apart from cylinder 4, which is very wet with what smells like fuel..

I swapped the plugs too, still no difference, so now im running on plugs and coil packs from my other car which I know are all fine, and its made no difference..

Im trying to think what it is, seems that there is no spark/ignition on cylinder 4, but what could be causing this?

My only thoughts was something to do with the connector that plugs onto the coil pack??

Any help would be appreciated!!

Thanks

Jonny

[snapey]

sh*t the bed, can you not check the line voltage to the plug and check it against the supply the other three plugs are receiving to make sure its arcing.

Might be worth going over all the connections with some contact cleaner to remove any dirt, water etc to make sure there are no shorts etc.

I'm not very clued up on car electrics by any means but 9 out of 10 electrical problems at work on the engines are down to sh*tty connections.

Is the car not under warranty?

Might be worth ringing the bloke or gal you brought it off to make sure he knows something you don't.

Luke

[MAT ED30]

Take it for a spin and try do some logs to check all is doing what it should

[jonnyc]

sh*t the bed, can you not check the line voltage to the plug and check it against the supply the other three plugs are receiving to make sure its arcing.

Might be worth going over all the connections with some contact cleaner to remove any dirt, water etc to make sure there are no shorts etc.

I'm not very clued up on car electrics by any means but 9 out of 10 electrical problems at work on the engines are down to sh*tty connections.

Is the car not under warranty?

Might be worth ringing the bloke or gal you brought it off to make sure he knows something you don't.

Luke

Good idea, yeah I thought initially that it was something a lot more serious in the engine but it seems like its electric, not that it makes it any better.. Just there a bitch to find the problem most of the time!

I haven't heard of anything like this before so trust it to be on my car!  

Take it for a spin and try do some logs to check all is doing what it should

Need to do some logs of it when its on idle.. It hardly runs so driving it about at the min isnt really an option.. 

[SteveP]

I would have though a connection issue with the coil pack would throw an open circuit error TBH 

Could you try with the coil pack on cyl 4 disconnected to see if it does throw an error?

[MAT ED30]

How old is the car and how many miles has done? And I am sure on vag com if you go into engine u can check for missfires and also do a readyness check to make sure all things are working as they should but do this test without the engine on, and you can also check each of the cylinders for missfires and also check the coils with the engine running

[MAT ED30]

Could it be down to the inlet Mani sticking as this can make them missfire

[four!]

Perhaps a quick compression test, compare with the 3 good cylinders to rule out mechanical damage on no.4 ?

[jonnyc]

I would have though a connection issue with the coil pack would throw an open circuit error TBH 

Could you try with the coil pack on cyl 4 disconnected to see if it does throw an error?

I did go through them disconnecting to see, with no.4 unplugged it ran better than with it plugged in.. With each of the other 3 unplugged it was running even worse (probs only on 2 cylinders)

I have only had it on a code reader, and not Vagcom, but to be fair they should see the same things..??

How old is the car and how many miles has done? And I am sure on vag com if you go into engine u can check for missfires and also do a readyness check to make sure all things are working as they should but do this test without the engine on, and you can also check each of the cylinders for missfires and also check the coils with the engine running

07 and 35k.. I have done a readiness check, all was ok..

Need to do some much deeper digging..

Could it be down to the inlet Mani sticking as this can make them missfire

Possibly, never heard of this before, dont fancy removing the inlet manifold myself to be honest, dont know how this would make just one cylinder not fire??

Perhaps a quick compression test, compare with the 3 good cylinders to rule out mechanical damage on no.4 ?

I need that doing yes, I really hope its not, but I think there is a chance its done a piston / ring..

[snapey]

I'd just take it into Audi on Monday matey, save yourself a load of stress.

I might sound quite negative towards it by saying that but that’s what I'd personally do with it being under warranty.

Luke

[jonnyc]

I'd just take it into Audi on Monday matey, save yourself a load of stress.

I might sound quite negative towards it by saying that but that’s what I'd personally do with it being under warranty.

Luke

Yeah, could well be the best way mate..

[Hurdy]

That's not good at all!!

If it does turn out to be a Piston/ring, you have to look on the bright side and get the forged rods in there whilst it is opened up to repair it.

Hope it isn't though and ends up as an easy fix for you.

[jonnyc]

That's not good at all!!

If it does turn out to be a Piston/ring, you have to look on the bright side and get the forged rods in there whilst it is opened up to repair it.

Hope it isn't though and ends up as an easy fix for you.

Well I did that that haha.. Arrgh.. Just P*ssed me off because I cant drive it!

[Cooper]

Could it be down to the inlet Mani sticking as this can make them missfire

Possibly, never heard of this before, dont fancy removing the inlet manifold myself to be honest, dont know how this would make just one cylinder not fire??

I had the inlet manifold replaced under warranty when my GTI developed a misfire so could be this! Was only misfiring on cylinder 1 aswell!

[illyun]

Hope you get it sorted Jonny... surely the seller must have known about the fault    At least its still under warranty. 
Sorry couldn't be of any help though