I'm beginning to think this isn't a lift pump issue. The 03's are known for hard starts/no starts when an injector(s) starts to fail. The injector bleeds off fuel pressure while the truck sits. For whatever reason, removing the stock filter and replacing it (or even just opening the filter housing and closing it back up again seems to net a few more starts). It's impossible for the owner to test their injectors individually, but you can try an impromptu test in your driveway. Once you get the truck started, slowly bring the RPM's up to 3000 then release the pedal. The rpm's should fall to idle in under 5 seconds (4 is even better) without "hanging" anywhere.


Can you smell fuel in the oil?


I had an issue where my rpms wouldn't drop to idle without hanging at 1200 for a second or two. The harder I worked the truck, the longer they would hang there. Took it to friend who just also also happens to be a Cummins tech. He did the diagnostic tests which pointed to at least one failing injector. Changed all 6 (you'll not like the price) and problem solved.

If the truck passes this simple test, then I would look for either fuel bleeding back toward the Raptor (leak between CP3 and Raptor) or a restriction (or air leak) in the fuel line between the Raptor and the tank (ice in the line, suction tube sucking to the bottom of the tank, loose fitting pulling air in with the fuel) .

For your CP3, the Raptor should be set for between 15 and 17 psi. Supposedly, anything MORE will make them a bitch to start.

 

Thanks, will try that out and see what happens. SO, just went outside and tried to start her, nothing, removed the filter and within a few seconds she fired right up I am now starting to think there is something in the filter housing that is restricting flow. When I pull the tank in a few days I think I will pull the filter housing as well and cleaning her out really well.

Will let you know about the RPM test, thanks again.

 

Mine had the same problem with the hard starts to not running right before I bought it. It was my buddies truck and he never messed with the filter, but like dieseldudes truck, the problem was the injectors. Thank goodness I didn't have to foot that bill. Sorry, not trying lower your hopes. Hopefully it's just something with your housing. Good luck!

 

The more I think about this, the more I think I am loosing prime and or sucking air. The reason I say this is when I was replacing the fuel pump with the Raptor I had to remove the old adapter from the inlet side of the filter and replace it with the one provided in the Raptor kit. What I noticed is the Mech had put the old adapter on and did not replace the bad O-ring, left it in and also put another O-ring over it . If he did a shady job on an easy adapter like that, what else did he take short cuts on . My next option I do believe is to remove every fuel line in the truck, check for any bad threads, or O-rings, then replace and torque to specs. This I HOPE will correct my issue.

 

Just change the suspect fitting first! Work your way back one at a time!