Cummins or Cat, both engines used an intake manifold heater grid; like an over sized toaster element; for pre start diesel warm up. To the best of my knowledge , they do not delay engine cranking , but only illuminate the wait to start light. The grid is only used when intake temps are below approx. 55f , if you're at warmer temps, than that, and have a cranking delay, ignition switch, starter relay or starter solenoid , are possible cause of the problem.
BUT: Always allow the dash system to complete it's bulb check before cranking, the control modules , really don't like that interrupted.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.