2000 silverado 4.3l to 6.0l swap...wont start

[wesleyland]

I now do have a 99-02 pcm and harness, all of the connectors match up. I have a sensor here or there that arent the same but nothing that shouldnt hold the truck back from starting. I spoke with the guy reprogramming my ecm and he thinks its a security issue where thins cant communicate correctly.

[Frenchy]

VATS needs tuned out. There's also a ground, drivers side, bottom of the engine block. If that's connected, the truck will crank but not fire.

[wesleyland]

yea he is suppose to take VATS out and tune it. Im sure if i got a 2000 - 2002 engine it would have made simpler since pins changed in 2003. But since i have 2003 engine, the harness and pcm of a pre 2003 v8 so it will pin correctly to my truck. It should work unless I am forgetting something.

[farmtruc]

does the engine have spark and fuel while cranking

[wesleyland]

yea it is dumping fuel to the fuel rail. Spark I am not so sure of. But I do think the previous pcm was a bust and halfway worked. I should be getting a new one in end of this week.

[farmtruc]

if the injectors are squirting fuel, it's not vats.

[wesleyland]

hmm ok, I know the security light inside the pickup keeps blinking security when the key is forward or i try to start it.