Suggestions-Getting Pre-Ignition/ Detonation

I need a little help here…

I’m Running a B18c1 with 11.5 to 1 Wiseco pistons and stock fuel system exept for an adjustible FPR…

I appear to be getting Pre-Ignition only at low RPM under under a load. This only started after i put my Chipped P28 ECU in ( no Knock Sensor) . I could just swap my P72 back in but it runs alot better with the Chipped ECU at High RPM. I do have an A/F ratio gauge ( not sure if it’s worth a Sh*t) it shows rich at the point i get pre-ignition. I’m running stock NGK ITR plugs.

I’m still kinda of a noobie at this so if i’m leaving out important info please let me know… Any help would be great.


What gas a ya running? Base timing ya at?

93 Oct

16 degrees

Well then I say its gotta be the chip. From what I read about most chips are kinda crude that richen the mixure put and advance the timing. So maybe the chip isn’t for running the high compression as you are and its over advanced timing is causing the pre ignition. And the no knock sensor may be a problem too because it cannot retard the timing when it “hears” the pre ignition knock. I never had a chip, its just what I read at one time so take my stuff at .5 a cent. Whats my solution? Hondata, thats what I am getting soon…I hope

colder plugs fixed it… :slight_smile: :rockon: :rockon: :rockon: :rockon: :rockon: