Trouble shooting my 100% stock 1990 GXL.
After working my car, (Replacing OMP and ECU) my car is still running very rough. tests show that the Leading coil is not firing at all. I have replaced Plugs and wires with NGK . Using a timing light, I see that the Trailing coil is firing and thus the car will start, but is very rough. I had a extra (stock) leading coil and it gave the same problem.
To prevent anymore throwing of tools and loud vulgar language in my garage.... I would appreciate some suggestions of what to look/test for.

 

The coil needs proper grounding to work so it has to be bolted firmly to the fender surface and the surface should be clean. Additionally the Black/Yellow wire to the coil needs to have 12 volts w/key to on. if that checks out then the other wire which is Green/Yellow is the trigger wire. If the main pulley was rotated by hand and w/key to on the voltage should alternate between two numbers and those numbers are 0 volts and 5 volts. The main pulley can be rotated simply by rotating the alternator pulley. The voltage reading should be 0 volts and briefly changing to 5 volts before returning to 0 volts.

 

Are there any fuses or relays to check?

 

If your trailing coil is working then no.

 

Check the wires Satch said to check.

 

All of the Electrical Tests that Satch suggested were done and the output is correct.
Soo, since the power coming into the Trailing Coil/igniter is correct, and the Wires and plugs are new, then it appears that I have a bad coil. I will be getting one soon.
The part that still concerns me is that the engine runs VERY rough and smokes a lot.
I understand that the Trailing coil is mostly for emission control and that the car should be able to run on just the Leading coils. I have a feeling that both coils may be toast.
I'll see when I get a different set of coils next week.

 

I find it weird that you tried 2 coils and both didnt work. have a feeling its not your coil.

 

I also thought these wouldn't start without the leading firing

 

It would likely struggle to start but it should/could start.

 

If the engine was running on just the trailing coil then that would explain the roughness etc.