Hey I have just replaced the wiring loom on my motor and connected the fuel pump relay and EFI relay as this motor is in a Patrol now it want start ECU has power got spark got fuel pressure to the fuel rail but wont start it fired once but thats it? How do I test my injector pulse and are the a earth signal to cause the pulse? ---------- Post added 29-09-11 at 21:15 ---------- Just to add the loom was out of a Manual if I have got a Auto ECU could that cause me probs?????

Injectors are always powered on one pin, and the other pin is switched to earth through the ecu. Hold a long screwdriver against an injector with your ear hard up against the grip of the screwdriver......like a doctors stethoscope. You should hear a distinct "click, click, click".

Thanks for your help.. I have found the fault there it 2 Power supplys to the Injectors one from the ECU and the other from the reverse polarity relay that I dont have in my new loom, as far as I understand it stabilzers the voltage when cranking cause when I hold 12v on the injector wire it start and if I disconnect it will keep running

Quote: Originally Posted by bj290 [View Post] Thanks for your help.. I have found the fault there it 2 Power supplys to the Injectors one from the ECU and the other from the reverse polarity relay that I dont have in my new loom, as far as I understand it stabilzers the voltage when cranking cause when I hold 12v on the injector wire it start and if I disconnect it will keep running Good to hear it's sorted. I'm going to get pedantic here, but the circuit is as i described above - power is fed from the reverse polarity relay, passed through the injector, then the ecu switches it on/off to ground. With ignition on engine off, if you measure the voltage at both injector pins with one lead on ground there is voltage on both pins because the ecu has switched the injector off. Because there is no voltage difference across the injector, no current flows and the injector stays off. When the ecu switches it on, one pin on the injector effectively becomes ground. Therefore there is 12v across it, current flows and the injector opens. It's nothing to do with stabilization. Hope that helps future troubleshooting.