Cp4 GMC Duramax conversion to cp3 common rail high pressure fuel pumps or similar.

[Rvrrat14]

My 2015LML has CP4. GM’s setup was a bit better than others with an additional return line. Seems folks had been running truck with low tank and on slopes would suck air, or so they said. I always kept mine 1/2 full at minimum.
I used Stanadyne Lubricity Formula (same on my tractor) since day 1.
I also put on an Air Dawg II lift pump just for safety. Never had issues and sold to my good friend. He’s still running it with zero issues.

 

[Hay Dude]

My 2015LML has CP4. GM’s setup was a bit better than others with an additional return line. Seems folks had been running truck with low tank and on slopes would suck air, or so they said. I always kept mine 1/2 full at minimum.
I used Stanadyne Lubricity Formula (same on my tractor) since day 1.
I also put on an Air Dawg II lift pump just for safety. Never had issues and sold to my good friend. He’s still running it with zero issues.

Before my CP-4 was replaced, I ran Hot Shots through mine while I waited for my replacement date to arrive.
I honestly believe my truck would have run for years more with it, but since Ram replaced them all free of charge, you’d be crazy not to take their offer. Ford stuck their buyers with them and made them wait till they failed. Not sure what GM did, if anything.
I feel for the guys stuck with the potential glitter bomb, but as said before, the failure rate isn’t all that bad….unless it happens to your truck.