The car randomly doesn't want to start, and each time it fails to start, I find I have no injector pulse.

I just wanted to be able to trace the wire back from the ECM and check it all out before I go ordering parts. Might just be a dodgy wire.

Also, the signal that goes to into the ECM, what is it exactly? And how can I check if its present?

 

On the ECM, check the pin F10 on C3 (dark blue wire) with the key on. You should see cca 40Hz signal (reads usually as 2.5V on a voltmeter) from the VATS box to the ECM telling it that it's-all-good and the ECM then allows the engine to start.

So if you're missing that signal on that wire, you might have a bad connection on the key resistor pellet or on the wires that go from the ignition cylinder to the VATS box.

Hope this helps.
Lou

 

Yeah mate, thats what I was after.

Unfortunatly That wire is only seeing 5V. Even with the 2 white wires in the orange sleeve under the column disconnected.

Could this mean my key is buggered? I'm have a HUGE problem getting a resistance value of it. The multi meter flicks up some very low number occassionally (life 180 or something) but nothing constant.

 

You're seeing 5V on the dark blue wire? 5V AC or 5V DC?
If you're seeing 5V AC, that should show as 2.5V DC.

Where were you measuring the resistance? On the key itself? On the wires on the steering column? If on the wires, then yes, your ignition cylinder might be a little messed up. I'd do a search in this forum and see if anybody had a similar problem and maybe solved it by cleaning something. Easier things first, before replacing the cylinder.

Hope this helps.
Lou

 

Your right, it was 2.5V I stuffed up. Ok, so if thats present, why arnt my injectors firing? What else could stop the pulse signals from working?

 

If you are absolutely sure that you have enough fuel pressure and you have power to the injectors, I would check the inj. actuator wires on the ECM (connector C2: dark blue on C11 and dark green on C12) and also the distrubutor reference pulse input wire (connector C2, pin D8, purple/white).

Other than that, I'm out of ideas at this minute.

Hope this helps.
Lou

 

Yeah mate. Just wanted to repy and let you know how things went. It was all a problem caused by the 12V feed wire to the 1,3,5,7 injectors was shorting out onto the injector driver wire.

Both wires to that injector were pulsing in sync, so the injectors never fired. All re-wired now and the car starts and runs like a champ!

 

Good to know.
Enjoy your running car now!

Lou