Engine/Transmission (1998.5 - 2002) Starting issue

[nfox]

My friend just bought a 98. 5 24v cummins and he said the previous owner installed a new lift pump 9 months ago and the guy that owns it now just installed a new fuel filter. He said it will start right up sometimes and other times you 'll have to crank it for awhile. Is there a spot to check fuel pressure on these 24 valvers, i have no idea as i am a 12v man? Any other things to look for, maybe a failing vp44, hope not!! He said the truck doesn't miss or anything, but power seems flat to him after 2300rpm. Any advice?

 

[justinp20012500]

There is a schader valve on the inlet of the vp... You can make, or buy a simple mechanical guage from Genos Garage and check the FP.

 

[isb360]

On the 98. 5's there are two test ports in the top of the fuel filter housing, one pre-filter and one post-filter. I think the threads are 1/2" NPT. Both ports have bolts in them from the factory. The one that is closest to the front of the truck is the post-filter pressure. Check pre- and post- to check for drop across the filter.



No need to tap into the VP44.



The factory shop manual also describes a detailed procedure that steps you through different diagnostic steps to verify the lift pump is putting out fuel, etc.



Hope this helps.



Tim

 

[nfox]

Lift pump

When i turn the key to the run position, should the electric lift pump turn on? What do i need to do to get the pump to turn on, and i would assume when the pump is running there should be battery voltage feed wire powering up the lift pump? These 24v are foreign material to me. thanks!!

 

[Hohn]

First, the test ports on top of the filter housing are 1/8" NPT, not 1/2 npt-- same as grease gun hose.



Yes, the LP should run when you turn the ignition to "on". It will run at a low voltage setting for about 10 seconds, or until the engine is cranked and started, then it will go to full power. Typically, you'll see like 5psi when you first turn the key ON, then it will come up to 15psi+ once it's started.



Justin

 

[mhenon]

LP

I thought the lift pump didn't start to run unless you "bumped" the starter. Like after you've changed a fuel filter or something. . you need to bump the starter without starting the engine. . then you can hear the lift pump running.



Mike

 

[nfox]

We'll my buddy showed today with his 98. 5 24v and we installed a new fuel filter and fuel pressure gauge, fuel pressure is right where it is suppose to be, turn the key to run and had 5 psi and bumped the starter and had 17 psi, and did that 4 times and it still took a little cranking to get the truck started, is that normal? Then we went out for a test drive and the gauge never went below12psi at wide open throttle, truck is stock. Then we went outside of town about 4 miles and talked to some friends of mine and was there for hour and a half and went to leave and the truck would crank and crank no start, fuel pressure would come up as soon as the key was turned on, so i cycled the pump 3 times and it cranked for 3 seconds and fired right off, it don't miss or shake or smoke, it started up and idled normal and it revs right up when i hit the gas pedal. Any ideas on what to check next? My buddy has a friend with a scanner so they are going to hook it up and check for codes and see what he figures out. Thanks for the help so far i will let you know if we figure anything out.

 

[B.G. Smith]

https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=103217 Check the above thread, some similarities. bg