1993 Cummins N14 ECM issues

What is your alt voltage? Check grounds! There is a search block on the top right of your screen. Some you tube N14 stuff is pretty good.
When wiring starts being cobbled up like that it is the beginning of of a long term on going nightmare. Boss is better to send to out for repair if needed. Finding someone to trust is hard.
I wish I had just told a boss that 34 years ago on a job. He keep pushing me.
Well do the best you can do, you have all day.
I did not have training on those. They did not have the equipment to test it. The vehicle broke down and the driver had to walk. Then I was dirt.
If you were working on my vehicle I would request you take some time and work through the simple stuff. But please do not go jumping wires.
JMHO and good luck. There are some people on here that can help you a lot. They have helped me tremendously. Work on that and let us know.

 

First of all, I would check the main power to the ecm. There should be 2 fuse holders connected directly to the batteries positive terminal, and the other ends go to the ecm. These wires and fuse holders get corroded over time and should be checked, cleaned or replaced to make sure the ecm has a good clean supply voltage of 12 volts. Also make sure the engine, ecm, and frame are well grounded to the negative battery terminals. Then check your 5 volts coming out of the ecm at the various pins with no sensors connected.

 

Miracle man over here. But not on something I cannot see and touch.

Please whatever you do don't go jumping wires. Use the ones the factory gave you. What always happens is you jump wires, whala shes alive and 6 months later jump more of the same until there is a ball of wire smoking in the mass pile.

If that truck is sick enough to visit hospital, er dealership then let them have at it. They would likely be overjoyed to work on a museum antique rather than the over engineered computer stuff today.

 

Majority of electrical faults are related to the wires. Sensors are more likely to fail than ECM's. ECM itself is usually pretty bulletproof. The last thing listed in most troubleshooting procedures is the ECM.

Being that the truck is 26 years old, I would start with a thorough inspection of the engine harness, plugs etc. Pay close attention to anything that doesn't look "original". Most wiring failures are from previous repairs/alterations.

I wouldn't tap into another power source. Sometimes the ECM reads voltages being sent/received in order to determine fault conditions.

Also verify that the ECM is getting keyed power, constant power and ground on all applicable pins.

 

Call Midwest ECM repair. He can tell you if your problem is likely the ecm or not. He'll repair your ecm or exchange it. Better quality than Cummins & much less expensive.

 

I have a Cummins isx and a code reading sensor supply voltage it deratred on me got it to a shop and it ended up being the pressure sensor...there's like 5 sensors that work on circuit 1 so the truck shows different codes but this guy knew about it and I was back on the road in a hr

 

Glad you found a good guy. I thank you should do him a favor? and post his shop.