An independent shop and a Cummins dealer couldn't solve this man's dilemma. The truck continued to lose power until he finally decided to take it to a shop. It ran but barely. Problem not solved. Truck towed to Cummins. Problem not solved. Now the truck won't even run. I have gone over all their work. Fuel side of the equation checks out. I have found the ecm doesn't have keyed power. The 4 battery posts are hot. By using a meter I have found there is no continuity from the key to firewall connector.
If I have read Pushbroom's diagrams correctly the #23 wire at the key should power #26 at the ecm. I have continuity from the firewall to the ecm. I don't have juice on the truck side to the key.
Am I on the right track? Any suggestions are greatly appreciated. Btw. This is a no pay job for a friend. A challenge I couldn't resist.
95/95 379 no start
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by bigguns, Dec 8, 2019.
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Check the fuse panel first for blown fuses or corrosion buildup in the fuse panel and also check for broken wires and good ground
bigguns Thanks this. -
Ring @pushbroom doorbell see if he’s around. I’m guessing N14?
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From the thread title I think you are saying it's a 1995 379 pete. Have you checked the main cab breaker? Look at the dash The far left side is a piece about 4x6 inches. Remove that and there is a big breaker behind it. Power goes to that before going to ecm/dash panel and ignition key.
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Correct 94/95 Pete. N14 Celect. Rolls over but will not start. On the actuator plug that goes into the ecm, #s 20,21,22, and #23 are hot. They are the 4 battery hots. #26 I thinks is the keyed hot and it isn't. Sorry for the crappy explanation. I can get the last 6 of the engine s/n and truck #.
Oxbow Thanks this. -
Engine is 11771433 from factory.
#26 should be the key power at the ecm like you figured.
On these older trucks the diagrams suck. Ill see if I can remember and pull out the big book tomorrow and work and look a bit more. Ill attach the cab diagram but its horrible to read compared to the new ones. It sounds like you are on the right track however.Attached Files:
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pushbroom I appreciate your last file of wiring diagrams BUT I can't make much sense of it. What I need is a diagram showing the wire(s) from the inside firewall connector to the key switch or from that connector to the point where it gets juice for the ecm. I have traced from the ecm to the firewall but I'm having trouble getting to the source of power.
This job isn't a priority so there isn't any hurry on the help you provide to me.
I may need to open to tight fabric weave around the harness just inside the cab. That will give me easy access to following wires. I'm trying to avoid untying as much of the harness as possible.
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