This is a C-Series Cummins in a 1994 Class A motorhome. I fired it up the other day and it started Bang(!) right away like always. Ran for maybe five minutes, happy idle, then shut down. Won’t start again. It cranks great, tries hard, but not even a cough. No smoke. I suspect the fuel cutoff solenoid but I manually blocked it open and no difference. Here is one clue, as I crank there is no movement of the tachometer. Normally when cranking the tach will show a few hundred RPM but now nothing. Can’t find a single fuse or breaker that isn’t working. Ideas?

 

I would imagine it probably has a mechanical injection pump correct? No electronics?
If so it may be a lift pump its hard to say might try a shot of ether and see if she fires. not to much though .

 

It has a new lift pump, and new filters.

 

Might check the crank sensor if the tach isn't moving.

 

That's a thought. Is there a quick test for that?

 

should get a k ohm reading of some kind you would have to locate it and unplug it.
check it with an ohm meter but i wouldn't think that would keep it from running if it has a mechanical injection pump.