Engine/Transmission (1998.5 - 2002) What's the Minimum Lift Pump Pressures allowed?

[Challenger-II]

At what point do you say, "time to replace lift pump"? My idle pressure is 11-12psi and I can pull it down to 7psi if I stand on it (w/ EZ box) real good. Cruising on highway... . about 10psi.



It has been this way for some time and doesn't appear to be getting worse? Can I live with it and will the dealer replace it under warranty with these pressures?



Thanks!

 

[gsdog1]

Honestly, not bad pressures. That's about what I see with a new lift pump and my current mods. I do want more pressure for other mods, and upgrades to my fuel system are on the way. Others with more experience will help out on the pressure numbers.



I will say this, with that kind of idle pressure, the dealers are going to tell you to have a nice day..... and should you decide to take it in, you will probably want to take the box off. If you don't do that, you will most likely be told to fly a kite!



Matt

 

[Walleye mike]

I see the same readings. I put a new lift pump on to get the WOT reading a little highter but had the same numbers. So I put the old one back on and kept the new one for a spare.



Idle I do get 13, cruise 9-10, Wot 7

 

[JPLB22]

I'm not really sure but I don't think the Dodge dealer will even test your pressure any more. I believe they are testing volume now. They disconnect the banjo on the bottom of the fuel filter ( post '99 ) and bump the starter, I think anything less than 45 oz. in the time the LP is running, than they will replace.



As far as acceptable pressure I think that really boils down to what you are comfortable running. As for as I know there are no concrete numbers on what the VP44 can and can't handle. I used to think that just so long as the pressure didn't go in to the negative I would be fine. But I feel differently now.



As of right now I am totally stock for fueling and my pressures are:



13 psi at idle

fluctuating 8-11 psi freeway

6. 5 at WOT



I am not comfortable with these numbers, so I am babying the truck. I have a brand new LP on the shelf in the office, am just waiting for the Wildcat Max Flow Kit to arrive.



Sorry to be so long but I am very interested in this subject



Jeff

 

[KLockliear]

I wouldn't run it with less than 5-6psi at WOT.

 

[Challenger-II]

Thanks everyone!!!



Seems like my pressures are not that bad. Pressures are a little higher when the EZ is out of the picture.



It's my original Pump and has 85,000 miles on it too!

 

[slo-ryde]

Cummins is using the volume test too, not just DC. If the volume is less than 45 ounces post fuel filter they start tracing the problem back from there (fuel filter, lift pump, mesh screen in tank, clogged lines, etc. ).

 

[gsdog1]

Interesting info!



Last time I visited the dealership ~ 3 months ago, they wouldn't even quote me a price for an off the shelf LP without a fuel pressure reading. For which, of course, I was to be charged for as a diagnostic test.



Something about a restriction??



Matt

 

[BarryG]

I was just in a local shop the other day to order an exhuast. I have been using these guys for several years. Anyway they get rebuilt vp44's from a big name vendor at least in town here. Inside the box is a sheet of paper that reads Warning warranty will be voided if failure is due to bad lift pump. Anything below 10psi at idle or WOT is the recommended minimum operating psi. I know they are just doing some major CYA there but they are the only authorized Bosch shop here in Denver so I suspect they see a lot of them.