Engine/Transmission (1998.5 - 2002) confused about fuel pressure

[GW01]

i have a 99-24 valve dually and i just installed a westec fuel pressure gage. at idle i have 8psi and 2000rpms about 5 psi. i think this is low so i called 3 dodge dealers in my area. here are the answersne said 40-50psi[wrong answer]one said 12psi at idle and one advised to disconnect fuel line ,bump lift pump and pump fuel in a bucket and measure the fuel in oz. i have read alot of the post about fuel pressure and the more i read the more i get confused. does any one have any suggestions. also i have 64000 miles and the original lift pump and no mods. thanks:--) :--)

 

[JR2]

I think your best option is to go to the nearest Cummins parts counter and buy a new lift pump( unless you have an extended warranty).



8psi and idle and 5@2000 is low. I know Dodge changed the way they diagnose lift pumps to a pressure and flow, but I can tell you for sure that 8 at idle is not good. I don't have the part number for the lift pump handy, but I know its a bunch cheaper (try 50%) if you buy it from cummins rather than the dealer. You can replace the pump yourself with out too much trouble.





Good luck and if you need directions for the lift pump change out check out this recall notice from dodge. The recall part does not apply, but the directions for changing the lift pump do. I would however reccomend changing it out from the top of the engine instead of doing it from the bottom. You don't have to pull the starter that way. Its a bit harder, and you can pull the fuel filter off if you want, but pulling the starter is a pain.

 

[JKuehl78]

I just put in an Autometer FP and its readings are bit sparatic. It's electrical so I'm not sure if it's the sending unit or just where I mounted it (it's in the brass plug in top of the filter canister) I idle at 15psi, cruise around 13psi and WOT at 10 psi. This is with 275 injectors, I took the comp out because I just put in a new VP44 and lift pump. I have a Wildcat Max Flow kit not yet installed, I ecpect my numbers to increase as this is what others report. I had to switch out pumps around 72,000 or 83,000, I don't remember, so you may want to look into a new lift pump before your VP goes. LP's are only $150, VP's I think are around $3200.



That's my thought, hope this helps,



Jeff

 

[thejeepdude]

Originally posted by JKuehl78

LP's are only $150, VP's I think are around $3200.

Actually, VP's can be had for as little as $800 if you know where to look, not including install. A modified VP with ~20% better flow can be had for about $1500 or so. That's the route I plan on going if my VP ever bites the dust. Even at those prices, a good lift pump is stilll cheap insurance!

 

[JKuehl78]

Originally posted by thejeepdude

Actually, VP's can be had for as little as $800 if you know where to look, not including install.

WOW!! I had no idea. Where? I may buy one just to have in stock.

 

[JPLB22]

If you are still interested in doing the flow test, I believe that 45oz. is the lowest it should be. That is with the key off and doing the starter bump to run the LP for 22 seconds or so.



Also I think that you need to catch the diesel from somewhere post filter ( whether that be coming right out of the filter, or at the VP fitting ). Anything lower than 45oz. than the dealer should replace under warranty. But a really healthey LP should be somewhere in the mid 50's oz. 's



All this info is from a dealer in my area, so take it for what it's worth.



Jeff

 

[thejeepdude]

Originally posted by JKuehl78

WOW!! I had no idea. Where? I may buy one just to have in stock.

I haven't had to buy one so I can't remember exactly where, but I know someone posted in a thread somewhere that there was a place in Texas that sold them for that cheap. Someone commented that the price was lower than their dealer's cost. Search the VP44 threads and I'm sure you'll find it. If you really have 800 bucks to keep a spare handy, can you pick one up for me too?



Edit: It was this thread that RobbyRam said he got one for $750 bucks...