Anyone happen to have any experience with a misfire on cylinder 1 CEL?

My car has a fairly standard Science of Speed stage 2 kit with a reflashed ecu.

I have ruled out coils by swapping, new plugs, valve adjustment. Injectors passed oscilloscope, new map sensor, strong vaccuum although slightly fluctuating at 20-21 in hg at idle.

Car gave compression of 240, 240, 235, 240 psi, a leak down is pending, but i suspect with compression that strong it wont tell me much.

The car idles fine in closed loop with afr at 14.7 to 15.1, then cycles every minute or so to way rich at 13.5 then off the charts lean at 16 (as far as my autometer o2 reads) at which point it MIGHT throw the CEL. I dont feel it misfiring it just throws the CEL, other than that it drives fine.

Im thinking possibly a tuning issue? I can try to contact blacktrax for a touch up tune but I cant seem to figure out what the cause is...

 

Whats the gap on your plugs? And what plugs are you using?

 

Is ur auto enter gauge narrow band ? If so forget about looking at it useless....

 

I believe they are NGK laser iridiums and gapped at the standard 0.044, however the car is at my mechanic so I can't say for sure.

Its a wideband, my next thought was that maybe my O2 sensor could be on the way out, but I feel like that would be giving me other issues, and the cyclical afr reading would be more erratic.

Maybe I should just try disabling closed loop?

 

.044 sounds too big. Try a smaller spark plug gap. I would start at .030.

 

X2

 

X3 4 and 5 lol

 

I'm not sure about the exact gap, but was told that they were re-gapped smaller.

Would too large a gap cause it to lean out only at idle? I mean my AFR's are rock solid during partial and WOT accel and even being held at partial throttle at say 2 or 3k rpm.

 

What size injectors? The oem wideband is not going to trim the fuel as perfectly as it would with stock injectors. It's trying its best.

Have you replaced the factory wideband or is it the original one that came with the car? There was a service bulletin on the sensor which required replacement to a new part number. Your factory wideband may be bad. Mine crapped out as soon as I flashed the ecu for the first time with flashpro.


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They should be RC Engineering 650cc's. I bought the car from a friend 6 months ago, and it ran just fine up until earlier this month, and it was well sorted other than this recent p0301 business. Even made a 1000+ mile road trip from SF to LA without a hiccup. The previous owner was super meticulous and it should be up to date with any service bulletins, but I will check on the o2

When your o2 was going bad did you get repeated p0301s? or did you get a P1149 or similar flavor?