C180 (W203) Misfire

[derekpayne]

Hi

I have a C180 (W203) which has developed a misfire on 1 cylinder (currently the OBD2 is telling me its number 3) have swapped the plug with number 2 but still showing as number 3, it only happens when its cold, warm it up, turn the engine off, wait a few minutes, start it up and its cleared.

I have swapped the coils of 2 & 3 over, it didn't missfrie at first but after about 1 mile it started, had the laptop connected to the OBD socket and it still said that number 3 was missfiring, so its not the coil pack.

The only thing that keeps occuring in red is the following "Fuel System 1 Status - Closed Loop Control but Fault exists" then it changes to amber showing "warm up" and then to green "normal operation".

It would appear that the misfire is only apparent when I have driven about a mile from cold, it then starts misfiring on 1 cylinder (number 3) and if I stop for a few minutes, turning the engine off, when I restart, the problem has gone away and the engine is running fine.

Maybe something to do with cold running and the fuel system?

I have just put my OBD on it and have got the following:

Fault code - P0303 - Cylinder 3 misfire detected
Fuel System 1 status - open loop control - warmup

Freezeframe:

Fuel system 1 status - open loop control due to system fault
Calculated load - 85.1%
Coolant temp - 64deg C
Short term fuel trim bank 1 - 3.91% lean
Long term fuel trim bank 1 - 7.03% rich
Engine speed - 2323rpm
Vehicle speed - 28mph

Hope that all helps to diagnose this fault.

Cheers

 

[jaymanek]

You need to do a compression test to rule out burnt valves which are an issue on this engine.

 

[derekpayne]

Thanks for your reply.

I dont think it is the valves, as if it was, the misfire would be there all the time and more prominant on tickover, it feels more like either an electrical fault or high pressure fuel like an injector, as I have ruled out both the plugs and coil packs, I have just swapped numbers 2 & 3 injectors, if it happens again and its now number 2 thats misfiring then I know its an injector faulty, if its still number 3 then we have to look deeper into the problem.

Cheers

 

[Alban]

clear the fault code and fix the problem.

 

[BlackC55]

Thanks for your reply.

I dont think it is the valves, as if it was, the misfire would be there all the time and more prominant on tickover, it feels more like either an electrical fault or high pressure fuel like an injector, as I have ruled out both the plugs and coil packs, I have just swapped numbers 2 & 3 injectors, if it happens again and its now number 2 thats misfiring then I know its an injector faulty, if its still number 3 then we have to look deeper into the problem.

Cheers

Do as compression check as advised. The missfire from a valve not seating properly can come and go.

 

[derekpayne]

Just as a matter of interest, I swapped numbers 2 & 3 injectors over last Thursday just in case it was number 3 injector faulty etc, but I have not experienced any misfire since Wednesday last week, maybe it was a bit of sh1t in number 3 injector?

All seems fine now, will let you know if anything else developes.

Cheers

 

[MphumiN]

I have the same misfire problems on my W203 C180 2004. It was caused by a sustained oil leak into my coil sockets because my tappet cover was worn out. I replaced the gasket cover and the car ran smoothly for about two weeks. Now the car is misfiring from cylinder 2 and 3 where most of the oil had leaked. Is it possible that the oil leaks damaged the coils now they need to be replaced? The car is consuming fuel at a meteoric rate and its jerky.