Engine won't start - no ignition pulse or spark?!

[rickardss]

Hi,

Can anyone help me to work out why my L92 won't start?!

Checked power to all coils, injectors, cam and crank sensor, etc. All seems fine & grounds, continuity and resistance tests also seem fine.

I don't have an injector pulse - checked with NOID light. Also don't have spark when cranking - checked by pulling a spark plug & holding against the block.

Cranking is fine but that's as far as I get. I will check the pulse signal on the cam & crank sensors tomorrow. With key on, both the positive voltage & signal wires have 5 volts present. Will try and check for the on / off variation in 5 volts on the signal wire.

[rickardss]

So I have rpm while cranking every time (approx 153). Engine ticked over once but thats it.

Cam and crank sensors seem ok

Can anyone help with ideas?

[MonzaRacer]

Coils and injectors should be fed by ignition voltage.
Verify that. You also need to make sure the ecm is getting a crank signal.

[rickardss]

Thanks Lee. ECM was receiving crank signal & there was voltage at the coils and injectors.

Seems the problem may have been fuel pressure. With the OEM harness changed (fuel pressure sensor removed) the ECM was only turning on the fuel pump momentarily with key on. While cranking it didn't appear to turn the fuel pump back on and therefore no pressure to the injectors. I wired the pump so that I can manually turn it on & off via a relay which seems to be working ok. Just means ECM wont be controlling fuel pump on/off.

[eldogg]

I always try to spray a little starting fluid in the throttle body. Instantly you know if it is fuel or ignition related.