Hi all,
I'm working on a 93 mighty max, 4g64, with a no spark condition. I'm fairly sure the ECU is the problem, but thought I'd run it past some experts, see what y'all have to say.
Like I said, no spark condition. Coil power supply is fine, and I can make the coil wire spark manually grounding/ungrounding the signal side of the coil.
Distributor seems to be working. Both signals are present manually spinning the dist when removed from vehicle. I also swapped the dist for one out of a 94 that I had lying around, no change.
The rotor spins when engine is cranked. Timing belt is present.
Checking for signal coming into the ignition control/power transistor, I find no + coming from the ECU to that unit.
Wiring seems to check out. The dist signal wires at the ECU show decent continuity. I hadn't backtraced the signal wire to the ignition control/power transistor, but that grounds out with the key off - I believe that shows continuity to the ECU there. No break to ground on any of these wires.
The main ECU relay is clicking, and also swapped that around with one out of a 94 for giggles. Don't think that's the issue..
So, to my question, are there any other sensors or relays that could shut off spark at the ECU? For instance, is there any security system that could shut down spark? Or, anything like an ASD relay on these? Any other things you might think to check? Or, is it pretty certain that the ECU is at fault?
Thanks for your time and any suggestions.