I'll sum up the problem first and then go into great detail
I've got a 1994 Pathfinder that cranks but won't start. There is no spark while the engine is cranking but there IS spark when I turn the distributor manually with the ignition turned to "On". I can hear the fuel pump and injectors but I haven't checked fuel pressure yet as the no spark on crank has me stumped. Also, after trying to start, the #6 injector will click constantly. The injector only does this after a failed start.
Read on for the whole story:
This vehicle had a bad automatic transmission but the engine ran fine. I sourced a donor vehicle with a working transmission and much lower kilometers. Pulled both the engine and transmission from this vehicle but due to some unforeseen complications with the donor vehicle, I decided to only use the donor transmission and the original engine. As it sits now the vehicle has original engine, original harness, and donor transmission.
After hooking everything back up, the engine would crank but wouldn't start. After some listening/checking I found that there was no spark coming from the ignition coil. Checked connections, continuity, resistance, etc and couldn't find anything wrong.
Entered self diagnostic mode for the ECU. Got 5 red flashes followed by 5 green flashes. According to the manual, this means there are no faults detected.
Started replacing ignition components taken from a running engine. Swapped the distributor, power transistor, and coil. No change. Swapped a known good ECU, no change.
Checked various voltages. Only found one problem. The voltage going to the power transistor dropped from 12V to 9V during cranking. The manual claims 9V is too low, 9.5V or something close is the minimum. Installed new battery. No change.
Tried self diagnostic mode again, still no faults.
Starting to get desperate/crazy at this point. Removed the distributor from the engine while keeping it hooked up to the harness. With the ignition switch set to "On", I can rotate the distributor by hand and hear the fuel pump, injectors firing, AND I GET SPARK! Put the distributor back in, try to start.... no spark.
Read about the ignition switch going faulty where ignition circuit isn't energized when the switch is turned to start. Tested the ignition switch with a multimeter and everything checks out. Tried a known good ignition switch, still no spark.
Still no faults on the ECU.
Help?
