Hey guys, got a 1995 NF Fairlane with no spark.

Car cranks fine, have 12v at the coil coming from the ignition when on reds.
The 3 yellow signal wires that come from the ECU all have 12v, but no pulse when cranking, they all stay at 12v.

Injectors are pulsing so no issue with fuel.

Have a new battery connected to it, has a new cam sensor that tests fine at around 1100ohm, crank sensor also tests fine at around 360ohm, tried a new crank sensor to be sure but no difference. Also tried 2 different ECU’s with the exact same code as the original (4DMF), still no difference. Have tried testing for coil pulse as well as cam/crank sensor readings at the ECU and getting the same reading as the engine bay so wiring looks fine. I though it would be an ECU problem not sending a pulse signal to the coil but all 3 ECU’s cant be faulty.

I’ve exhausted every option I can think of. What else could cause no coil pulse? Have I missed something obvious here? Should there be 12v coming out of the ECU to the 3 yellow signal wires. I’m at a complete loss here. Any suggestions would be greatly appreciated.

Thanks guys.

I think you should check that the ECU is receiving proper power and ground signals. If the ECU isn’t powered correctly, it won’t function.