i think that your biggest points here are:
1- The main relay needed replacing (a likely reason for the parking lot failure)
2- you are getting erratic action for both spark and fuel, but something at least
3- you were having a problem prior to your current problem.
4- you have an ecu, cam and crank sensor, igniter, and coil that worked in other cars.
To me it seems like a bad ground that finally crapped out...particularly an ecu ground. or maybe a fusible link? I dunno, but I will certainly bet that this problem has something to do with why your main relay went bad.
I will also bet that all your old sensors, coil and ecu are still fine
Now someone correct me if I am wrong, but the fuel injectors always get voltage with the key in on, when the tooth on the crank passes the sensor that causes the voltage to drop to whatever injector corresponds to crank position? Thus opening the injector for a brief moment?
You checked that you were indeed getting 12v to all three power supply pins in the harness with the key on
The fuel injectors are getting 12v as well
You checked the starter switch as well? That one is supposed to get voltage only during cranking (pin 81)
Just for grins check the voltage at the throttle position sensor. It's one of the few sensors you can test without the car running and that isn't a pain to get to. If you are getting 5 volts at the positive and whatever voltage at different throttle openings then that is a good sign because the ecu is sending something.
This kind of wacky electrical work is why I like using a power probe instead of a multi meter. All you have to do is touch the probe to a wire and it tells you whether its a ground, a pos (with or without voltage) or a faulty wire if there is no sound. and you can push the button to supply 12 volts instead of screwing with a jumper wire. The only con is the cord is kindof a pita
If I were in your shoes (meaning in no particular hurry ha), I would just start at the top of that pinout and check as much as I can without the car running. I would take a couple of hours to look at the diagram and find the wire color as well and label the important ones so I don't have to look at the stupid pinout so much. Lol
If I found any goofy readings, (especially any of the circuits that get voltage only when cranking) I would cut the wire for the grounds and ground it nearby to see if it changes.
Then I would ask General Disorder if I can borrow his cool scope haha
Just a side note, While stripping and testing my wiring harness, I noticed that the grounds tend to be rather sensitive. At first I just gathered them all together, I believe there were five wires and three body ring connectors to put a bolt through. Well, at first I stuck a bolt through the rings and vice gripped it to the negative terminal. That didn't work well. Neither did simply vice gripping them all at once to the terminal.
Only when I separated them and vice gripped them one at a time did they work reliably. And I was kindof freaking out because I was getting weird action at the main relay, and faulty readings at the ecu. There were wires f**ckin everywhere! haha.
I guess the point I am trying to convey is that by all appearances those grounds were fine and would have even tested fine, and were indeed (at times) fine! But just the slightest movement of any wire would cause one or two of those grounds to act up and it would frustrate me to no end. Until after about two whole days of struggling I finally realized that half assing the ground wires the way I did is what caused me a pile of grief
Edited by sparkyboy, 21 January 2018 - 04:45 AM.