LT4Hawk9

New LS3 crate engine, came from S&P. We got it turning over tonight, and it was not firing and trying to start at all. We got out the little handheld spark tester and it was showing lit up whenever the ignition switch is on...we confirmed it with a timing light...nearly constant spark on those two cylinders, even when not cranking. We can hear the plugs buzzing! We unhooked those two coils, and tried a scanner, but it will not make electrical connection to the engine. What the flip?

Everything seems hooked up properly, and the grounds are all good. I plan to call S&P in the morning, but thought someone on here may have an idea of what to check, so that I can sleep tonight.

If this harness needs to go back to S&P, I may need bail money.

fire67bird

The inability to connect a scanner has me leaning on a bad pcm or something isn't connected correctly. The coils shouldn't be getting power without cranking the engine.

LT4Hawk9

This is with the ignition switch on. I'm totally confused.

V8Rumble

iTrader: (9)

Hey Mike - I don't know for sure if this will fix the problem or not, but trace your RED injector signal wire back & look for anywhere that it could be shorting out. (I'm basing that on the fact that today I've been doing research on how to do my own engine harness, & I just happened to watch this video today - if you skip to the 4:00 mark & watch it for a couple minutes -while writing down the colors he mentions- you'll see why I immediately jumped on the RED wire. But seriously - trace it back through the harness, keep the "noid light" on it while wiggling the wire harness - and I'll bet you'll find the problem in short order!)

Good luck man, I hope this helps ya!

V8Rumble

iTrader: (9)

I think that everyone on this particular board knows that feeling!!