Engine misfire?
Discussion
PH Collective,
I'm after some help. After spending all day trying to sort my engine I am out of ideas
I have a Pug 406 Coupe with the later ES9J4S V6 3.0 engine. When it gets warm it seems to start misfiring. I put it on the diagnostics which say misfire in cylinder 2. I swapped the coil with cylinder 1 and the fault stayed with cylinder 2. I swapped the plug and injector with cylinder 1 and it still said misfire in cylinder 2. I swapped the plugs / coils / injectors from the back 3 with the front 3 and still the same misfire with cylinder 2 reported on the diagnostics (I cleared the faults between each change, its not the same registered code).
If I disconnect the injector to cylinder 2 I can hear the engine revs lower as it struggles to adjust. If I disconnect the coil, it does not change the engine note. If I pull the coil out slightly I can hear it arcing against the plug. Putting another plug I can see the spark arc against the engine when its put close. Compression is around 175psi on all 6 cylinders, so its not HG failure.
Cylinder 2 has a spark, it has fuel & it has compression. I'm flat out of ideas. Any suggestions would be much appreciated!
I'm after some help. After spending all day trying to sort my engine I am out of ideas
I have a Pug 406 Coupe with the later ES9J4S V6 3.0 engine. When it gets warm it seems to start misfiring. I put it on the diagnostics which say misfire in cylinder 2. I swapped the coil with cylinder 1 and the fault stayed with cylinder 2. I swapped the plug and injector with cylinder 1 and it still said misfire in cylinder 2. I swapped the plugs / coils / injectors from the back 3 with the front 3 and still the same misfire with cylinder 2 reported on the diagnostics (I cleared the faults between each change, its not the same registered code).
If I disconnect the injector to cylinder 2 I can hear the engine revs lower as it struggles to adjust. If I disconnect the coil, it does not change the engine note. If I pull the coil out slightly I can hear it arcing against the plug. Putting another plug I can see the spark arc against the engine when its put close. Compression is around 175psi on all 6 cylinders, so its not HG failure.
Cylinder 2 has a spark, it has fuel & it has compression. I'm flat out of ideas. Any suggestions would be much appreciated!
I'm no expert but it would suggest a wiring problem between between coil/Injector and ECU or as suggested above an ECU problem.
First step, if not checked already, I would check and clean up the engine earth strap, that can give all manor of weird faults which you wouldn't believe possible. Then check wiring and clean the wiring connectors back to the ECU. If still no joy then you could try making up a jump lead to bypass the existing wiring from the coil to the ECU (assuming no box of tricks in between), then do the same again for the injector wiring.
Then I would try and borrow an ECU to iron that out (if you have access to one try that first, guess most people don't though).
After that a box of matches and a gallon of petrol does wonders!
First step, if not checked already, I would check and clean up the engine earth strap, that can give all manor of weird faults which you wouldn't believe possible. Then check wiring and clean the wiring connectors back to the ECU. If still no joy then you could try making up a jump lead to bypass the existing wiring from the coil to the ECU (assuming no box of tricks in between), then do the same again for the injector wiring.
Then I would try and borrow an ECU to iron that out (if you have access to one try that first, guess most people don't though).
After that a box of matches and a gallon of petrol does wonders!
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