oldgoat69

It is finally dry and sort of warm here today. The suspension is all done so lets got for a ride. Not so fast! Upon attempting to start the car I get no fire.
It cranks just fine.
Fuel pump runs.
I have 12 volts to the coil packs.

What is weird:
I show 14 psi boost with the key in the run position.
I get no fire to the plugs using a timing light to show fire.
Temp shows 55 degrees, it is 43.
I show no DTC's.
Car ran great when I parked it in early February.

The combination is a 2003 LQ9, Stock PCM with a very basic tune.
Any ideas?

Brian68

PCM/frame/engine grounds?

oldgoat69

Everything tests good.

99MUSTANG5.3L

Are you certain that you're getting 12V at the coils while cranking?

oldgoat69

I will check again. For sure in run position.

99VetteFRC

Sounds like PCM is shutting off the coil signal for some reason. You should be able to test the signal circuit from the coil to the PCM with a LED test light. Hook the clip side to Bat+ and the Test light probe to the PCM signal and crank. The LED should blink. If not sounds like PCM issue. Could be something telling the PCM not to fire. Also check Injector pulse, usually if PCM shuts off coils it shuts off injectors too, even though the pump still runs.

oldgoat69

Thanks for all of the ideas. I figured it out. It is something in the ignition switch. I bypassed the switch (hot wired) the main power and it started right up

99VetteFRC

Glad it wasn't anything to serious.

Doug G

I hate electrical gremlins