I have a 1996 Silverado 2500 manual 5.7 and the white plug on the ecu fried. Pin 17 and 18 are fried. Now the truck won't start. It did before and it started cutting out and eventually died. Now it just cranks. I have no spark and can not seem to get spark back even with multiple ecu swaps. Any ideas? Pin 17 and 18 are grounds so I have tried to just ground them to get the truck to start but no progress. I also cannot find a wiring diagram for where pin 17 and 18 go to to check them, they should be grounds but with key on pin 18 seem to get power. I just want to get the truck running before I spend any real money on it. Any input would be great, thanks

​​​​​also I have a new crank sensor, new ignition module and coil

 

Thanks

 

Welcome to the forum. I'm moving to the truck section of the forum where you will get more views.

 

Those circuits are supposed to ground at point G120 on the top right of the engine, next to the throttle body.

That ground point is shared by multiple components, inside and outside the cab, including several components used for engine control and starting.

If excess voltage is present on the wires when disconnected from the VCM then there could be a short in the harness or one of the other components using that ground has shorted.

What is the voltage reading with the VCM disconnected? Keep in mind less than 0.5 volts is normal as there’s always a “residual” charge on any ground wire that’s spliced into other circuits.

 

I will check tonight when I get back in the garage and get back with you.

 

I might have been wrong about pin 18 getting power. The multi meter says there is no power. I must have been checking a different pin and got them confused. They both have no power going to them. I have 12v at the pink wire to the ignition module
but no spark

 

Just about every major engine control component relies on battery voltage with the key on.

The ignition control module, ignition coil, cam sensor, crank sensor, and fuel injectors should all have battery voltage at key on.

The ignition supply circuit for the engine is the pink wire and almost all of them receive power from the ENG and ECM fuses in the underhood fuse block.

I’ll try to get a wiring diagram posted in the next couple of days.