Ill try to keep this short. I always wait for the wait to start light to go out before cranking. Two weeks ago I started having a hard start situation that randomly would occur. If I stayed on the ignition it would eventually start after about 3 seconds. If I let off and immediately tried to start again would fire right up. So I started to observe things and heres what I found out.

If I turn on ignition and the wait to start goes off but I do nothing. Just before all the indicator lights finish going out, the wait to start light would come back on and the lift pump would cycle as if I had just turned on the ignition switch, ie the fuel presure would hit 15 psi, and drop back to 2. As long as I delay starting in anticipation of the second wait to start light I never have a hard start. So this is the problem. Any ideas why 2 wait to start cycles occasionally?

 

That doesnt sound normal. Have you checked to make sure all connections and grounds are secure? Have you checked for codes?

 

Not checked for codes. It is rather weird. Happens about every 3rd or 4th start. I am waiting to see if it gets worse. Wasn't able to find anything like it on search.

 

Next time take notice what the overhead display says when you try to start up and experience the hard start or double prime.

 

FWIW it has to be pretty cold for the Cummins to need to cycle the grid heaters. Most marine Cummins don't even have a heater.

Gota be something (check valve, etc.) that keeps your pressure in your rail. My be the pump itself. Might look there.