Hello everyone!

My son and I are working on his 2004 chevy trailblazer with the 4.2 i6. Last year around emissions time, chasing down codes led us to find out there was some excessive crankshaft endplay ( sounds kinky ) going on, and we secured a used good 4.2 to swap in. Many hours and weekends later, the engine is in but we are having some problems. The replacement engine came with a PCM, which while on would not get the starter to turn. We swapped it to the PCM from the old motor, and voila the starter will turn the engine over...but the truck won't catch and start. We are at a loss now as to what to try next. We have checked all connections and grounds and everything seems to be ok.

The fuel pump does not seem to come on at all when turning the key or attempting to start. I'd think I would be able to feel or hear the pump going from under the vehicle, and I can't.

We just really aren't sure exactly what to look for or try next. Anybody got suggestions?

Oh by the way, this motor swap is a huge pain in the ass if you were wondering.