Does anyone know why I would not have 5 Volt power or power to my fuel pump relays coming from my ECM? Pins 48 and 50 have a 12 volt supply and pin 49 appears to be a good ground.
This is an '02 24 valve 5.9 with the manual six speed. It has an Edge Juice Tuner. The engine was transplanted into this 80's Chevy truck several years ago by someone else who I do not have contact with. The PCM is bypassed. The truck was running fine on the 30 minute drive to pick up my trailer. I shut it off while I connected and then it would not restart. The engine will run if the lift and injection pumps are hotwired. The Cummins Bus pin 2 (+) is supplying 4.2 volts. The Cummins Bus pin 12 (-) is supplying 1.2 volts. Both busses are now supplied through the edge.
Thanks

 

Does anyone know if the Cummins buses are supposed to change voltages based on some input?

 

It turned out to be a fried transceiver on the circuit board in the tuner.

 

Update: While the tuner was fried, that wasn't the actual problem. There was a fuse hidden up under the dash behind the gauges that popped. This fed pin 5 on the ECM. Once I gave it power again, it started right up.