No Calpack Damage???

[turbojustin]

I just picked up a hybrid LC2 Blazer that is running a stock ECM. It runs rough when under boost and sometimes does not start. It just cranks over like its getting no spark. Fuel pressure seems good at startup and idle.

I opened the ECM and it had no Calpack in the socket. I replaced the missing calpack which turned off the check engine light, but it still suffers under boost and has the no start issue.

Also, the radiator fan never turns on. I tested the relays and they are good. The fan will turn on if I jump the relay.

Here's my question...Could this all be signs of a bad ECM? Could the ECM have been damaged from driving the truck with no calpack?

I have already replaced the following sensors with known good parts: MAF, Cam sensor, crank sensor, ignition module, and coil pack. Unfortunately, I don't have a spare ECM.

FYI: The truck has a Caspers modified stock engine harness. Also, the previous owner said the truck has ran this way ever since the engine swap.

 

[turbobob924]

Hybrids are tough to trace these problems!

Try checking the basics, there is a no start troubleshoot diagnosis checklist out there.

sounds like some flaky wiring and or grounds. Check that the ECM connections in the 2 big blocks are not corroded and there are not loose connectors. There are pretty small and easily get loose in the connectors blocks.

Check that you have a good crank signal at the ECM. The voltage of the crank ref signal should fluctuate as you crank the engine.