Discussion Starter · #1 ·
Ok, if you've followed the 8psi milled head post here is an update. I got everything installed and now there is a problem at high rpm....from about 5500 rpm up. It starts bucking a popping out the exhaust, kind of like hitting the rev limiter but less extreme. I also can see black smoke coming out the exhaust. It seems like the ignition is cutting out. The air/fuel ratio guage stays in the rich, I adjusted the SAFC richer and leaner and made no difference. I believe it is an ignition problem, but I have a Crane capacitive discharge ignition, LX91 coil, MSD distributor cap, brand new NGK plugs (1 step colder), and Nology wires. The ignition has been on the car for 6 years, I'm wondering if the coil is getting tired? The only fuel related thing changed was the fuel pump, I installed the 255lph pump supplied with the Jackson boost upgrade kit (had a Walbro 190lph in before). I'm going to try and gap the plugs a little closer and see what happens? Any other ideas? Remember my compression ratio is approx. 10 to 1.....and I'm very confident it is not running lean. I've got a steady 75 psi of fuel pressure and also have the 310cc injectors. I'm open for suggestions.