So I am still having some misfire issues with the new engine.
When I start the car from cold, it runs and idles as it should. All 4 cylinders firing. If I tap the throttle a few times the engine revs as it should but then it only runs on 3 cylinders when it returns to idle. It's always misfires on cylinder #3 when this happens.
Then when the engine is hot the misfire goes away on its own. I don't touch anything, it fixes itself.
When I am driving the car and its hot there is no misfire at all.
These are the things I have done to troubleshoot.
swapped coil packs around - still same issue, misfire cyl 3
swapped injectors around - still same issue, misfire cyl 3
I bet you all saying its the coil pack harness now, well I pull the plug off the cyl 3 coil pack, removed the coil pack and stuck a spare spark plug in the coil pack and connected the plug, it was firing away with a nice blue spark.
So I then check the plug, it was also firing.
I then decided to reduce the plug gap a bit as they were set to 0.8, I set them at 0.65. The car started and ran fine, so I thought I had found the issue. So this morning I come to start the car, and it runs even worse. Like only 2 cylinders firing, then dies and won't start again, smells like its flooding.
I then think maybe then big injectors are over fuelling. So I put the stock S3 injectors in and flash the stock S3 map. Unplugged the maf as its in a rs4 housing (thought scaling would be out)
Start the engine, it start but same as before, runs rough, dies and won't start again.
other things I have tried.
changed ecus - no difference
held injectors into a bottle to see if there are spraying - all ok
changed sparked plugs - no difference
changed fsi coil packs with new 1.8t coil packs - no difference.
Checked coil pack harness for continuity - only check as far up the harness as I could get to without removing the harness.
things I haven't checked yet, and plan to do.
check continuity from coil packs connectors to ecu connector - NEED TO FIND A ECU PIN OUT DIAGRAM.
check engine compression - dont see how the engine runs fine when its hot for there to be a compression issue.
I await solutions