Turbo Biscuit Posted December 14, 2012 Share Posted December 14, 2012 Hey all, new to Hybridz, been working on a '78 280z since March now. Had some good times and bad times but have learned a lot! I am having some issues with my ignition system. I've got the engine to purr pretty well, but it does miss randomly. The timing is dead on at 800 RPM, but it's still missing and I'm getting some crossfire on cylinders 1 and 2. When I swap wires 1 & 2 the crossfire goes away but the motor still misses. I can't tell which cylinder is missing, I'll leave the timing light on each cylinder for quite awhile and don't see any misses (even though I hear them), but when I hook it up to the coil-to-distributor wire I see the misses. I've replaced everything except the coil and wires (coil in the mail, had to return it to MSA because it was DOA), which it seems likely it would be one of them. However I was wondering if it might be the transistor module. I opened it up and would like to replace all the semi-conductors and capacitors. The board has been dipped in a "tamper proof" epoxy, but it melts off pretty easily. I was wondering if anyone has done this before I go reinventing the wheel. I couldn't find a datasheet for the power transistor, and the zener diode codes on the board aren't specific enough to find a direct replacement. If anyone could shed light on this I'd appreciate it. Thanks! Also, the coil on the 78 280z doesn't have a ballast resistor (there is a resistor for the tach down the line in the circuit), so I'm getting 12v AC on the coil. From my understanding the module limits the current on the '78 so as to eliminate the need for one, is this true? Quote Link to comment Share on other sites More sharing options...
EuroDat Posted January 1, 2013 Share Posted January 1, 2013 Have you tried downloading the FSM and doing the diagnostic tests on the ignition system? See link for manual http://www.xenons30.com/reference.html It has quite a good section for testing this. The only real tuning you can do on the OEM system is a variable 20kohm resistor in the temp sensor for the efi. Then you can adjust the fuel/air mixture over the hole rev range. Its a better mod than playing with the AFM spring tension. I have a 77 280z with ballast resistor. Didnt know a 280z came without... Chas Quote Link to comment Share on other sites More sharing options...
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