No spark, no coil pulse, have injector pulse

meat_ax · 2025-02-10T08:42:18+0000

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? I’m at a complete loss here. Any suggestions would be greatly appreciated.

Thanks guys.

newfutile · 2025-02-11T08:25:10+0000

Have you scanned for codes?
We don't have that vehicle here,does it have an imobilzer?
Most vehicles here need ecu pairing usually with vin number

meat_ax · 2025-02-11T11:01:40+0000

newfutile said:
Have you scanned for codes?
We don't have that vehicle here,does it have an imobilzer?
Most vehicles here need ecu pairing usually with vin number

Its a 95 fairlane, a lot of the F series in the U.S. use a similar ECU.
It hasnt thrown up any codes at all.
Imobilizer usually stops cranking, this cranks ok. Plus the imobilizer light is flashing as normal.

meat_ax · 2025-02-11T11:24:40+0000

newfutile said:
Have you scanned for codes?
We don't have that vehicle here,does it have an imobilzer?
Most vehicles here need ecu pairing usually with vin number

One thing that was weird, day before this happened, for about 5-10mins the car ran like ----, cylinder 1 wasn't working, pulled cyl 1 lead out and it had spark. blew out a whole bunch of smoke so I shut it off. This cant be a coincidence, just not sure how its related.