odd high rpm misfire

[mach1one]

I'm having an odd wot misfire in my 90 awd with the Gen2 maf. Here are the relevant mods

E16g with 3" exhaust @ 20psi
680 inj
255lph
FP2 cams
Base timing set at 5 degrees.
BR7ES @ .028

The car will start to lightly sputter then cut out. Before that it pulls and builds boost fine. It doesn't sound like a coupler blowing off, I've checked them all and they're tight.

It happens in 2nd @ 6k, in 3rd @ 5k. AF when this happens is high 10s. Logger shows 16-17 degrees, 4-5 counts of knock. PW is 90%.

I've checked the ECU, plugs, spark plug wires, coil pack was recently replaced. I'm running out of ideas. I previously had a FP Red on and acted the same for what it's worth.

 

[TurboChrged93]

Some questions. I see you have larger injectors. Did you put the "U" clips back on the injector pigtails to keep them secure? Base timing set with timing plug grounded? Adjustable fuel pressure regulator? What's that set @ with vac line off and plugged at idle? 255 walbro low or high pressure. What are your corrections set at on your maf2? Only happends under heavy or WOT? I take it by PW 90% you mean injector duty cycle? Tried BPR7ES?

 

[mach1one]

Base timing is 5 degrees with plug grounded, 255 low pressure. The maft is set to -30% at high load and I'm getting high 10s on a/f. And it only happens at WOT.

The 93% DC was at 36 base fp with hose on at idle. I upped it to 40 and leaned the injectors out. It still stumbled but not nearly as bad. I believe if I upp the base a bit more and lean it out it should clear out all together. I don't think these injectors like to be worked above 90%. The previous set I ran at 100%+ for a good while, never any problems. Thanks.

 

[mach1one]

Ugh. Problem still exists. Verified cam gears are correct, and tried a .025 gap on the plugs. Changed fuel filter, and verified fuel pressure is not dropping. No change. Injector clips are all on. Boost leak testing had no major, just some minor leaks that I fixed. The only thing I can think of is that its ignition related, but I'm not sure.


Any ideas would be greatly appreciated. The car sputters at wot above 5-6k in any gear. Up until that point it feels fine.

 

[JeffGST]

I would go even smaller on the gap.

Go even as small as .020 and see if that solves it. Right now, you need to use process of elimination and rule out on thing at a time.

Rule out the spark plugs first.