More help required with my S4 engine issue

[tonybolony]

Wow i am thinking i was never meant to have a nice B5 S4.

At last i got it through its MOT and road legal, got to drive it for all of a day then.......... while drive in started to seem like it struggled, so i floored it and all was ok.

But today, it idles fine, but seems to be missing, and then when you try drive it, it sounds funny, and really struggles to pull, making the car shudder. I was wondering where i should start my investigation to nail this problem so i can start to enjoy my BiTurbo .

Would be nice to actually get to use this car properly

 

[aragorn]

Boost leak test has to be your first port of call, along with a fault code scan.

dont thrash the car at all until you've done that and ensured everythings leak-free, or you will end up wrecking the turbos.

 

[S4_dan]

Coil packs do fail on these too. A vagcom scan should reveal any issues.

What condition are the spark plugs in?

 

[tonybolony]

will take the sparkies out tomorrow if its nice weather, so i will come back to you.

 

[tonybolony]

so i used a Vag com and it tells me there is open circuits intermittent on Cylinders 4 5 6, i checked engine management fuses and all are ok, so i am gonna take a guess that the coil packs are ****** ?

 

[aragorn]

maybe one of the ignition amplifiers?

 

[tonybolony]

ok am gonna be thick now, where is that located and how can i test it?

 

[Arrkon]

Isnt the amplifier inbuilt to the coil pack?

The coil pack is at the front of the engine i think. Measure the resistance between both opposing ignition (spark plug) lead connections on the coil pack, should measure beween 8-14k, the plug leads should measure 3-7k.

That is of course, if you pack looks like this:

 

[aragorn]

they're on top of the airbox, and theres two.

I guess you could swap them over and see if the fault moves to the other cylinders?

 

[tonybolony]

ok so its very hard to see anything in such a compact engine, can anybody point me to where the coil packs for 4 5 6 run to as its only that side that has the intermittent fault

please..... am going nuts not been able to drive this car after spending all the time getting it through its mot :-(

 

[aragorn]

I've already told you. The ignition amplifiers are on top of the airbox. swap them over and see if the fault moves to the other bank.

 

[tonybolony]

sorry mate, missed that bit, got a lot on my mind. Anyway i had a mess and try cleaning the contacts etc, and have now gone from intermintent 4 5 6 to open on just 6, then i swapped over, i got open on just 3 , then after went to intermitted on 1 2 3, so i am guessing a new ICM? , Also there is a K&N on my car (not by me) so the ICM were not on top of the airbox

 

[aragorn]

Bingo. Almost certainly a failed ICM.

If they arent fitted to the OEM heatsink that may well have contibuted to the failure. You should really get them fitted with a heatsink before the other one dies.

 

[tonybolony]

ok my next question is, other than a dealer can u recommend somewhere for replacements, or can i use a certain type? , cant wait to get this car on the road

 

[aragorn]

They probably have a bosch part number, so you could try your local motorfactors or bosch dealer and see if they can get you them cheaper.