sometimes spark, sometimes not

[Matt McClung]

Okay, I have a problem. I have injector pulse, and I have crank signal at the ignition module, and I have cam signal at the ignition module. All powers and grounds to the module are good. I have taken the coil off the module and have verified with key on, I have power at the coils, but when I crank I have no coil pulse on the three separate wires to the coil. But as I said before, I have injector pulse when cranking. I know that this would usually mean a bad ignition module, but I replaced it already and the new one does the same thing, except that sometimes when I turn the key on and crank it will spark for a second and the engine wants to start but that is it, no more spark. The new module is a BDI brand from Advance auto, and the coilpack is a brand new AC Delco.
Has anybody had any trouble with the BDI modules?

Thanks
Matt

 

[Matt McClung]

Wanted to let you guys know that I figured it out. I was running this through my brain and it hit me, if the cam and crank are not in sync, then the ignition module won't trigger the coil packs even though the module is getting good cam and crank signals. I just rebuilt the engine and when I put the cam sensor in, I was backwards and timed the cam sensor at 25 degrees BEFORE top dead center, so when I cranked the engine it would sometimes spark until the cam sensor triggered, and when the module saw that cam and crank were out of sync, it shut down the coils but kept giving pulse to the injectors.
Once I properly timed the cam sensor, it fired right up, and choked me out of course because of all the raw fuel sitting in the cylinders

Matt

 

["Turbo-T"]

Glad to hear you got it figure out. Still trying to make jive of cam and crank sensor stuff.

 

[87geeinn]

...choked me out of course because of all the raw fuel sitting in the cylinders

It's kinda bittersweet ain't it, when you're sitting there coughing going, "It's ALLLLIVE!!!"

 

["Turbo-T"]

...if the cam and crank are not in sync, then the ignition module won't trigger the coil packs even though the module is getting good cam and crank signals....when I put the cam sensor in, I was backwards and timed the cam sensor at 25 degrees BEFORE top dead center, so when I cranked the engine it would sometimes spark until the cam sensor triggered, and when the module saw that cam and crank were out of sync, it shut down the coils but kept giving pulse to the injectors.

The cam sensor...isn't it supposed to be set to 25 ATDC?

As I am still learning the ops fundamentals of the LC2 electrical ignition set up, I take it, that this is one of the module's jobs? To verify that the crank sensor and the cam sensor are sending the signal at the right time?