Gray is the correct TFI. I don't have anymore more trouble shooting suggestions. Sounds like you are down to PIP or TFI. Stopping with 0v on the coil green wire is not good. It means you have full power on the coil. The coil and TFI will overheat. In the old days they used a ballast resister to lower the voltage on the coil. The TFI controls the dwell time to limit how long the coil has voltage applied. In even older days, dwell time was how long the points were closed.
From your 1st post: The electronic gauges (LEDs) turn on with the ignition switch. That's good. When you turn on the headlights, the "cluster illumination relay" switches the electronic gauges power to the headlight switch dimmer circuit ( fuse 13). This doesn't work.
The B2 to I jumper test should only turn on the illumination lights that come on with the headlights, not the electronic gauges (because the cluster illumination relay stays in the ignition switch power position). All the stuff on circuit #19 LB/R wire in the diagram I posted should turn on.
Note: The B2 terminal of the headlight switch is labeled A in the wiring diagram.
If you plug the headlight cable harness back into the switch, will the electronic gauges now work with the headlights on?
hummm,, i think your learning me sumthin there,,,,,,!!!
the eec is in the game of spark control only if the spout is connected.
now there is a few youtubes out there and one specifically i can think of where a fox body guy has the EEC unplugged.
he cranks the engine and he has spark regardless of spout or not being undone.
Come on now. Pulling the Spout jumper and unplugging the EEC does the same thing. Opens the SPOUT circuit between the TFI and the EEC. Spoke too soon . EEC pin 16 is the ignition ground for the TFI. I am surprised you could spark with EEC unplugged.
I haven't forgot that switching the key off and back on makes the problem go away. All of the checks I suggested should be done without switching the key off. The TFI only operates independent from the EEC if the SPOUT is disconnected. When the SPOUT is connected, the EEC controls when the spark fires. This is how it controls the timing. If you are getting spark with the SPOUT disconnected and it still won't start: 1. It says the TFI is working. 2. There are other things the EEC is not doing besides not triggering the SPOUT, maybe like also not triggering the injectors. The EEC 5v power supply being out of specs may explain why it's behaving erratically.
then i should drive?????????????????????????????????
You can. It shouldn't hurt anything. You would be running at the base timing. I was thinking if when you have to coast to a stop, you unplug the SPOUT, and it starts without turning the key off, that eliminates the TFI as the problem.
Fuse 17, one of the fuses you said had been replaced with the wrong size, supplies the power for the cluster LED (Data) display. Except for when the headlights are on. The cluster illumination relay then switches the power source to the headlight switch dimmer control. Check to see if the LEDs light-up with the headlights on.