six months ago i had all eight injectors replaced..diagnosed as bad return rate...the past couple days here or there it would just crank, and ten minutes later of letting it sit, it would start. this morning, however, all it did was crank, not a slow crank, but just crank and not catch...normally after letting it sit for a few minutes, it would start...not today...injectors again??? i looked at my real time data w/predator and balance rates, rail psi, everything checked out once it finally started when i got home from work today....any ideas?

Loosing prime? If it's cranking and won't start purty much gotta be a lack of fuel....right? Once it starts then you would have all your balance rates and fuel rail pressure. Seems like the problem is getting the fuel to the injectors in the first place. That's my guess. Maybe crack the bleeder screw and pump to see if you get any fuel out of it. If you have to pump it a bunch you might not be keeping your prime. It's a good first step anyways.
JP

Had kinda the same thing happen to me and it was a cracked fuel filter houseing,,small pin hole

plenty of fuel at housing...a diesel mechanic said it could be filter head or cp3 leaking as injector return rates were perfectly fine...

Check the battery voltage while cranking it over-- if it is less then 10 -- :cool: may be batteries-- The computer needs more then 10 to turn on!

This is going to sound crazy, but did you have the block heater plugged in the night before trying to crank it that morning?

nope...happened last year during summer...dealer said injector return rate and replaced all 8. ive never plugged in heater. cranks plenty fast enough, plenty of voltage...i think its a cracked filter housing personally...we'll find out soon enough, she goes in next week.

Check the battery voltage while cranking it over-- if it is less then 10 -- :cool: may be batteries-- The computer needs more then 10 to turn on!

That's the TRUTH!! I had this happen and the dealer couldn't even figure it out. Then they charged the batteries to continue being able to crank for each test and walaa, it started right up.