rb cutting out at 5000rpm

[WarantyVoid]

i have searched all over, and i cant get this motor to run correctly. i have an 89 s13 with a s1 rb25 swapped in. i have a walbro 255 with a z31 fuel filter. i have a front mount intercooler, and a 3 inch downpipe and straight back 3" exhaust.


at around 5000 rpm the engine breaks up and i get clouds of black smoke out the exhaust. so i know its not a fuel cut. this leads me to believe it is maf or ignition related. the timing is set to 15* off top dead center. the ignition chip, and all of the coil packs pass the ohm tests. the spark plugs are ngk iridiums with a 6 heat range, and gapped to .80. i cleaned the maf with some spray contact cleaner today, and it didnt make a difference. i adjusted the tps into place. .45 when closed 4.5 at WOT. no noticeable difference. i am out of ideas. if any one has any ideas on how to fix this so i can enjoy my rb swap i would be eternally grateful.
thank you so much in advance.

[ANVIL]

a lot of times the coilpacks can pass the ohm test, but still be bad. they can fail under load, or ground out. read this whole thread

How To Fix Missfire Problem - Skylines Australia (http://www.skylinesaustralia.com/forums/Fix-Missfire-Problem-t119403.html&hl=coat+coilpack)

i would try this first. only thing is i wouldnt use tape, id coat it with urethane or silicone or something similar. do that and report back...

[Darius]

Everything looks normal. I'm with Anvil once again. It is probably a coil bleeding the spark to the head instead of pushing it thru the plug. Try coating the housings. If that doesn't work, get some LS2 coils and do some rewiring. POW!

[Norty]

Is that .80 in standard or metric. Either way stock plug gap for the rb should be .030-.035 thousandths. Sounds like you are blowing out the spark. Just something to check.

[Jtuned_andy]

.8mm or .030 thousandths should be a relatively stock gap