Problem starting diesels

[jrtracker]

Have a 2001 4100scb with twin Cummins 370 hp diesels. Issue is I have sporadic issues getting the engines to crank. When I turn the key the alarm sounds but the motor doesn’t crank. I’ll try the other motor and it may or may not crank. After trying for about a minute, they will eventually start. It seems they start once the preheat indicator goes on... does that sound correct that the preheat indicator must come on before they will start? Thank you

[Phillbo]

Yes, you need to wait for the glow plugs to heat up.

[dbriceno]

I has an issues with the wire from the batteries to the starter on one motor. There were some tight bends and the wire was corroded within the insulation. Replacing the wire took care of the issue.

[mmwjr]

I won’t think the glow plugs would prevent the engines from cranking, starting yes but not cranking. The cranking circuit the the ignition switch, solenoids and starter plus wires. Are the positive and negative wires clean and tight?

[shrew]

I used to have an old 1981 VW Rabbit Diesel that you used to have to wait for the glow plugs. Even when it's 50 degrees out, my Yanmar starts immediately. I don't even have a glowplug light to know when the glow plugs are warm.