12v Cummins Swap Wiring

[Jarrett Melvin]

So I'm getting close to buttoning up a lot of this project and firing it up.

More less looking for some reassurance or advice on wiring.

I've started to thin out and sort the harness for what I'll need and not need. It was and 87' tbi. I havnt cut or removed anything yet.

My thoughts are, I should only need my two alternator wires. I was able to mount and use the original alternator from the truck. The ignition wire from the fire wall. Big + from the battery to starter. Any grounds of course.

I have a green and tan wire aside for what was my water temp and oil pressure. I've got GM sensors installed for those. I got my fuel gauge wiring aside and as well as front and rear lights and such.

Is there anything I'm missing or should look out for? Especially grounds. Thanks

 

[Ricko1966]

Your alternator should have a total of 3 wires 1 exciter,1 current sensing,1 12v out. You are going to need a wire to engage the starter. I assume the Cummins uses a solenoid on the injection pump to shut the engine down,you can use your old 12v+ for the HEI to control this. Grounds,ground the engine well to the frame or battery,make sure the battery has large and well connected ground to the engine the frame,and the body. Everything else can ground through those components. The engine block or frame,or body can conduct more current than any wire on the truck.

 

[77Dmax]

Whats nice about GMs of this era is the computer harness is separate from the engine and light harness. All the computer stuff comes out of the right side and all of the engine/light stuff comes through the fuse box connector on the left side.