Help- 2016 2500HD 6.0 Crank/No start

[CHYKYNLIPS]

Pulled the truck up in the driveway to load trash then shut it off to go inside to eat lunch. Come back out 30 minutes later to leave for the dump and it turns over and over but won’t fire up. Sprayed brake cleaner in the throttle body and it fired up momentarily. Noticed the fuel pump isn’t running at key on. Checked the pump fuse and swapped relays with no change. No CEL or codes.

I know the FSCM was a problem on pre 2016 trucks, especially 1500s but can’t find much info about the 2015+ 2500 gassers so I’m wondering if they changed the fuel system electronics. Anybody have experience with this or have any resources I can check out?

 

[down_hiller]

push the schrader valve down under the hood on the fuel rail and see if fuel comes out. You should get a strong stream if the fuel pump is good

 

[down_hiller]

There should be one on the fuel rail somewhere

 

[CHYKYNLIPS]

I just read your post but already loaded the truck on a hauler right after lunch and it’s at my dads house now but after he pulled up with the hauler earlier, I went to show him how it was messing up and it fired right up. I turned the key off and recranked twice. We were talking about what it could have been while the truck was idling then after 30 seconds or so it started sputtering then shut off. Each time it fired up we could hear the fuel pump running prior to cranking. When it messed up again, we couldn’t hear the fuel pump. Seems there’s a relay somewhere in the circuit that’s failing. I already swapped the cube relay in the fuse box so it’s somewhere else. Haven’t been able to determine where or if the truck has a fuel system control module like the GMT900 trucks do but I’m guessing that might be the issue. We’re taking it to a local mechanic with a good reputation in the morning. Going to avoid the GM dealership for now. Too many nightmare stories for me to go to GM first. I’m pretty bummed about it. Hopefully it’s a clean cut diagnosis and not another sad story of a ghost issue that can’t be pinpointed.