When i want to start my truck in the morning or even let it sit for like an hour its very hard to start and i have to bump the key to let the fass run then it will start. i put it in the shop and they said it needed a new computer so i did that and it still didnt fix the problem it has a brand new vp-44, it has 20 psi on the fuel when running. imput please i am beating my head against the wall trying to figure this out.
The fault code that we need to be concerned about is P1694, it means that there is a communication problem between the ECM(Cummins controller) and the PCM(powertrain control module) . The modules communicate over the ccd bus. The ccd bus is a two wire communication system that allows the computers to talk to each other. This ccd bus is going down and causing your problems.
The first thing I would check is the main large connector in the fuse box in the engine compartment. Make sure the connector is bolted down all the way and you can't pull it up. I am thinking we are losing a power or ground to the ECM and we need to start by checking that connector and make sure all the fuses are inserted all the way.