Quote:
Originally Posted by Stl-986
RedTele58's post got me thinking (dangerous thing). I'm not too sure it is a connector issue, but it could still be a wiring issue, but this is where I need help understanding the wiring & coils.
When looking at the diagram the coil has 3 wires. 1 is +12v, 2 is ground. 3 goes to 42 welding point WL Motor, which I think goes to a relay if I am reading things right. The same ground is shared with coil 1-3, SAI pump motor & engine intake cooling fan motor. This ground is located right by the AOS & the outside corner of the intake manifold. Verified that it has 5 ground wires.
So, big question. If I disconnect that ground wire from the engine, should that wire still have ground connectivity? If I am reading the diagram right I dont think it should.
My question is if the gp 12 is disconnected from the motor, should there still be ground connectivity between those ground wires and ground?
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I may be totally off-base on this as I have no real experience on P-cars' electornics. Having said that, most cars I've worked on, the DME or ECU, or whatever they call it, does not send voltage, it completes the ground. So, my theory is that post #1 is NOT +12v, but ground for the Primary circuit (low voltage) of the coil (when the DME grounds it), #2, GP12, is the ground for the Secondary (high voltage) circuit. The diagram shows a diode for the spark plug side, which would be the main ground, so maybe GP12 is to ground some transient voltage?? And #3, VS42, is acutally +12v. This would make sense why VS42 would hit all 3 coils and other parts.
You can test this if you have a circuit tester and connect one end to any ground and probe #3 on the harness and see if there's 12 volts. And if you have and OHM Meter, you can probe both ends of all three wires to check for continuity or excessive resistance. I'd at least check for a broken wire by testing continuity before worrying about replacing the entire harness.
Hopefully this helps get you on the right track towards troubleshooting.
EDIT: Actually, you don't need to check both ends of all the wires. If #3 is in fact +12v and you get +12v on the #3 post of each coil, then those are all good. If you have an OHM meter, you can check for continuity from #2 to any ground on the car. The only wires you need to check both ends for continuity are the #1 wires. You need to probe them at the both coil side and the DME side to check for continuity.