Hi. I own an unmodified UK spec Fiat 124. Still the factory ECU map with a whopping 140bhp.
Previously I had a CEL for a cylinder 3 misfire. Changing the coil made no difference. When I removed the spark plug is was heavily fouled. It did look wet. Changing the spark plug or cleaning the plug instantly solves the misfire. The CEL clears and the car drives back to normal. This has occurred on cylinder 3 twice, the other spark plugs never have an issue.
Just out of interest I was playing around with OBD2 readers and noticed that when the car is idling at 800rpm and warmed up (so its closed loop), the Long Term Fuel Trim is always a negative percentage. Suggesting the car is running rich and its trying to back off the fuelling to compensate.
Any ideas is this is normal or what could be causing it?
screen shot from idling. The short term hunts around 0% as expected, the long term always stays around the -7 to -12%
Real time graph of various driving conditions. With a few steady gear changes at the start upto 100 sec, then a constant 3000rpm from 100 secs to 165 secs, then a lift off (coasting), idle at a set of red lights from 180 sec to 190 sec, then a short acceleration upto 5000rpm with 2 or 3 gear changes around 190 sec, then coasting again, then steady drive from 210 sec.
Previously I had a CEL for a cylinder 3 misfire. Changing the coil made no difference. When I removed the spark plug is was heavily fouled. It did look wet. Changing the spark plug or cleaning the plug instantly solves the misfire. The CEL clears and the car drives back to normal. This has occurred on cylinder 3 twice, the other spark plugs never have an issue.
Just out of interest I was playing around with OBD2 readers and noticed that when the car is idling at 800rpm and warmed up (so its closed loop), the Long Term Fuel Trim is always a negative percentage. Suggesting the car is running rich and its trying to back off the fuelling to compensate.
Any ideas is this is normal or what could be causing it?
screen shot from idling. The short term hunts around 0% as expected, the long term always stays around the -7 to -12%
Real time graph of various driving conditions. With a few steady gear changes at the start upto 100 sec, then a constant 3000rpm from 100 secs to 165 secs, then a lift off (coasting), idle at a set of red lights from 180 sec to 190 sec, then a short acceleration upto 5000rpm with 2 or 3 gear changes around 190 sec, then coasting again, then steady drive from 210 sec.