N14 celect occasionally shuts down

1994 White/GMC (Volvo) tandem dump truck with a Cummins N14 Celect diesel and 9 speed overdrive Road ranger trans. The "Engine Fluids" light will come on with a buzzer. The engine will derate and shut down. It will start right up again and may do it again 5 minutes later and it might not do it again for 2 or 3 weeks. There is no overheating problem and all fluid levels are fine. The check engine light has never come on and the diagnostic switch has never shown any codes. There seems to be no rhyme or reason
to when it does it; idle, slow speed, fast speed, loaded, empty, hot, cold, etc. Doesn't matter.

Over the past 2 years, we have performed the following work to this truck to
try to solve this problem:

1. Removed the instrument cluster, cleaned and applied dielectric grease to
the harness connection. All of the gauges appear to work.

2. Removed the low coolant sensor from the coolant reservoir tank, cleaned
and tested it. It appears to work. Of note, this truck has a 2 pin coolant
level sensor in the reservoir. The Cummins wiring diagram also shows a 4 pin
connector which appears to have a factory "shorting plug" installed.

3. Inspected miles of under hood wiring, cleaned and inspected harness
connections, checked wire continuity, etc.

4. Cleaned and inspected the 3 ECM connector plugs. Checked the continuity
on every wire in plug A, the sensor connector plug. Checked the 12 volt
inputs and grounds into the ECM,

5. Replaced the crank sensor, coolant temp sensor, oil pressure sensor, fuel
shut off solenoid.

6. Cleaned and checked engine and chassis grounds.

7. This engine has 3 coolant temperature sensors. One controls the fan. One
has a factory connector plug on it and goes to the ECM. We're not sure where
the wires to the third sensor go.

After all of these repairs, the problem still exists. COULD IT BE A FAULTY
ECM? The engine ECM for this truck: P/N 3619037, S/N 72557.

We desperately need to get this truck repaired. If anyone has any ideas I'd be greatly appreciative.

Brian

 

Thanks for your reply. Yeah, I'm lost on this one. I'm wondering if something could be going on in the ECM that is sending false info from time to time.

 

I truly appreciate all the replies from the group. I rarely let a troubleshooting issue beat me but this one really has me scratching my head.