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I have a 2005 Kodiak C5500 with a Duramax (LLY). Drove it about 200 yards and it died. I could get it to restart if I continuously pumped the primer on top of the stock fuel filter. Got it home and made the following "fixes".
  • New Fuel Filter. I have two DuraMax trucks so I have a lot of experience with this, and the priming process. Used AC Delco Filters. Result, no luck. Same issue, only runs when continuously primed.
  • New Fuel Filter housing and rubber hoses to the filter housing, as well as back to the tank. Another new fuel filter just in case. Result, no change. Still only ran when the primer pump was continuously pumped.
  • Installed New AirDog Rapter lift pump. This version is just the pump, still using stock filter. Also installed a 3rd brand new fuel filter just in case (New o-rings every time). New lift pump installation went well. Installed between the tank and the stock filter. I have a fuel pressure gauge on the lift pump. Running 10psi (which is stock and suggested as my engine is stock). Lift pump seems to work well. When I remove the air bleeder screw it will quickly pump out a ton of fuel. I have done this several times to ensure no air is in the system. Truck still only starts if I hand prime the stock pump and will only continue to run if I continue to pump the primer pump. I didn't think this would be an issue with a lift pump installed.
When the truck starts and runs (Only when continually pumping the primer pump), it sounds normal. No excess smoke, just normal idle. Won't really rev up well, but thinking it is because I can't prime the pump that fast.

As a recap, new filter, new filter housing, new hoses (nothing past the filter housing), new lift pump pushing 10psi. Still only starts and runs when I prime it. Am I forgetting something? Not thinking about something? Fuel Pressure Regulator??? CP3 pump???? Would it run when primed with a bad CP3?? Huge thanks for any help and advice.
 
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