i have a 99 3500 dually 5.9 Cummins turbo diesel. When it sits like over night it is hard to start but once it starts you can cut it right back off and it will start right back up fine. You can even start it up cut it right back off and let it sit for a couple of hours and it will start right back up this is in North Carolina so it is not cold here right now. Is this something else or would this inline fuel pump do the trick
thx

 

how is the fuel pressure?

 

i will check that as soon as i can thx
what should it be?

 

im in nc to i would check your batterys voltage intake grid heater and fuel pressure and even fuel filter

 

Finely got the pieces to connect my fuel pressure gauge to it.
When turning it over there is no pressure but as soon as i stop to let starter cool off it goes up to 10psi and bleeds back down to nothing. When it finely starts it is around 8psi on the input side and 5psi on the output side

 

input/output of the fuel filter or the lift pump?


either way, both are too low.

10-20psi at ALL TIMES. (other than engine off and lift pump not running...bleed down is perfectly normal as the injection pump has a fuel return that goes back to the tank)

This includes idle, cruise, and wide open throttle.

Ideally you want 14-20psi for better injection pump cooling and lubrication.

 

that was from top of the fuel filter i am pretty good at gas engines but i am learning on diesel engines and i really want to thank you for your help. what is wierd to me is when trying to start it i can not hear the lift pump running not sure if the engine is just drowning it out or what but as soon as I quit trying to start it it sounds like it starts pumping

 

normal operation should be: key on - pump cycles for 2-5 seconds as a quick prime.
cranking - pump should run at 25% duty cycle (7psi during cranking only)
bump starter but engine not running - pump will run 100% duty cycle for 15-30 seconds.
engine running - pump will run 100% duty cycle continuously until engine is turned off.

 

ok thx again