What would cause a loss of prime after cp4? I prime my system with everything hooked up and it will lose prime within 30 minutes. Once I unplug 3/8 fuel return line at firewall and plug it from cp4, it will hold prime.
Yes it does start once primed as hard as i can pump it. Without lift pump it will run until truck idle drops to normal idle from warming up. With lift pump on and set to 10.5 psi it will run and drive. Without the truck running does the rail pressure regulator (fpr2) hold the system primed? I'm wondering if that it allowing a small enough leak into the return line to the tank when the truck is off and sitting. (180k miles) Know what part of the system holds the fuel primed will greatly aid in troubleshooting.
Need to vacuum test the filter primer pump. Get a handheld vacuum pump with a separator likes those used to bleed brakes and connect it to the outlet line. Yes you remove the outlet line and vacuum test the primer pump on the filter housing. Should hold, if it doesn’t then primer pump and housing need to be rebuilt or replaced. Try that
Another great video Tony! Thank you for sharing your wisdom and knowledge. I am a novice shade tree mechanic enjoying learning about diesel engines. Question, I recently purchased a stock 80k mile 2013 2500HD with the 6.6 LML. Am I ok running the factory fuel system with OE AC Delco filter changing every other oil change or would you recommend a preemptive lift pump upgrade? If so what lift pump would you recommend? Thank you Sir!
Hello mr. Salas, well i have the lml duramax itsa 2011, its on a savana ambulance, it came to my jobsite because of bad shifting, it couldnt shift to 2nd shift. it had tranny valves stucked, but also has a failure with the injection system under load, when i shift to drive, injection pump fails at over 12,000 , neverthiless there are no codes on this one. what should i look for? i cannot command the duty cycle on the fprs, i only can see the injector balance rates, injector cutout seems to be fine, injection pump reaches to 25,000 on neutral, but under load starts failing over 12,000 psi as i told you above, when it fails like this, it smokes a lot gray/white smoke, coolant is ok, smells like diesel, only under load, i will tell you, it starts like a charm, no starting issues. what do you think? by the way great info!
Can you do a vid for a LML. I got a 2013 Silverado 3500 with LML. It's a crank no start. I hooked up scan tool and fuel rail pressure stays at 29 psi. Before and during cranking. Fuel pressure volt at .49 and unplug it goes to 5v. I hooked up gauge to test port and pumped it to 15psi and it held cranked it and vacuum went to about 4
I have not installed the CP3 on an LML. I have done replacements of the CP4 but I make it mandatory that we add a aftermarket lift pump upon pump and injector replacement. No issues! Thanks for the question!
