98 5.4L 24V long crank before starting

[haze10]

The truck is a 1998, 5.4L 24V Cummins, Ram 3500. A couple of months ago I lost the lift pump, which also took out the fuel injection pump. Truck has 125K miles on it. With both replaced, the truck ran good for about two months. Now, when the truck sits for a few hours, the engine cranks for about 5 to 7 seconds before it starts. It sounds like the engine isn't getting any fuel. So having read about the lift pump previously, I decided to try an experiment. I clicked int he starter for a split second, without starting, and left the key in the 'on' position. This is supposed to trick the lift pump to run for 20 seconds. I could hear the lift pump running, and after it ran for 10 seconds, I'd hit the starter again - engine will start instantly.

Any idea of what this might be. Lift pump seems to be running, Is there a check valve of some sort that might be letting the fuel drain back?

Any ideas would be appreciated. The rebuilt injection pump did come with new electronics. The lift pump I believe is a Carter.

thanks

 

[dapepper9]

Do you know how much the new carter lift pump flows? You may need to get something better that flows more.

I know vp44 trucks have quite a bit of fueling down low so if your lift pump is taking too long to supply enough fuel it might not start right away.

 

[haze10]

Lift pump was a direct replacement of original (I was told Carter). I wouldn't think flow rate would be an issue for starting or idle, only heavy loading.

 

[dapepper9]

I wouldn't either but the stock lift pumps are weak and if you got a cheaper stock replacement that'd be what I'm thinking. I very well could be wrong tho too

 

[MagSport]

It sounds like the fuel is draining back though. A check valve is a good place to start.

 

[MagSport]

I've been doing some research and there isn't a check valve on the pump but there is one on the tank. My guess is that check valve has failed.