LS Swap No Spark VATS?

[JimNazium]

I just put a 2006 LQ9 (Vortec 6.0) in a 1956 Chevy and I have no spark.

No Codes. All grounds look good.

Can the VATS prevent spark?

I was under the impression I could fire the thing up and the VATS would shut the engine down after 3 seconds so I could at least make sure it runs before I program the computer. I have not got the VATS removed from the PCM yet.

Thanks for any help.

[prozak567]

with VATS it should start for a second or 2 then shut down. do you have RPM showing when cranking it over ? you can check with a scan tool. bad crank sensor will prevent spark. Another common problem, is the wire people use to switch the ignition relay, has to remain hot while cranking.

[JimNazium]

Hey - thanks for the reply! A little late

BUT, your second comment was exactly what it was.
The old Chevy ignition switches would kill power to the ignition wire during crank. So, I made a little jumper wire, with a diode on it, that goes from the hot leg, during cranking, to the ignition wire and it works great.

Thanks again for your reply.

PS: In case someone else runs into this problem, I got the pic below and more info from the Online Hot Rod & Custom Car Magazine - MyRideisMe blog (I think).