Looking for advice. I was getting random misfires on my log runs. I changed my OE plugs for BPR7ES plugs, gapped to .026. All the misfires are fixed but I still get a lean spike/misfire past 7200 rpm. My AFR's all fairly flat from max boost to 7000 rpm otherwise. I'm running 21 psi, approx 11.0 AFR's, and I have zero knocksums. Should I worry about this misfire?

 

Whats your timing at and right before the misfire.

 

15 and 17 degrees. My ECU is staying within my high octane timing map. As I mentioned before - there is zero knocksum.

 

maybe its your rev limiter????

 

My rev limiter is set at 7700

 

If your below 500whp you shouldn't be having that problem at that timing level. You stared with the cheapest stuff first, the plugs. Do you have a buddy you can swap coils with?

Also does your timing map have smooth transitions where you are having problems. Like no big 3 degree jumps from one cell to the next. It try to keep jumps down to 1 degree from cell to cell but sometimes have to go to 2.

 

No access to coils. But I will look over my timing maps. Thanks.

 

Injector duty cycle too high??

 

Interesting thought. I didn't log my duty cycles though - dammit.

 

try 0.21 gap

 

Similar problem with my Green and S1's. This actually started before S1's but still on the Green. Random misfire/break up usually around 7K. Plugs were at stock gap so I dropped it 22. This didnt really seem to fix it so i dropped it again to 19 and while it was better its still not desirable to run that tight of a gap and it didnt fix it anyway. Alot of it seems to be boost related (30#) though and while I have a COP setup I have been busy with customer cars and havent gotten to mine. IDC's were at 80-81% with the FIC750's even at 30-31psi on the Green/S1 combo. Timing was in the 13-15* range on Turbo116.

 

Thanks for the input JohnBradley. I know it is not my injectors maxing out their IDC's. That should show up as a gradual leaning out, not a misfire spike. I'm still stumped but my car drives great. And this problem is only at 7200 rpm.

 

does it happen on lift-off?

 

It happens right before lift off.

 

11's is fairly rich. Shoot for 12's and see if it clears up the misfire up top.