Engine/Transmission (1998.5 - 2002) Stock Lift Pump Specs

[lfuchs]

Im Wondering What Lift Pump Psi Are Ok. I Installed A Fuel Gauge Last Week. Ideal 13. 5 Psi

70mph 8-9 Psi

On The Floor 3. 5-5 Psi



I Took It In Dodge To Have It Checked. ( I Didnt Know If Gauge Was Correct) They Me Tell There Is Nothing Wrong And Its With In Specs. But 3. 5 Psi Scares Me.

 

[Greenleaf]

I have one installed (on a 1999 model) and at slow idle I see 13. 5 and at WOT I see 6. 5. The lift pump is not new. It's well over 1. 5 years and 20 some K miles.



GL

 

[jeepit]

I too would like to know what are the minumum numbers. I have idle 12, cruise 8, wot down to 5

 

[Greenleaf]

My engine has a replacement injection pump and is 100% factory. Cummins manual states ; Run engine at high idle, the filter inlet pressure should be greater than 7 psi otherwise, there is a lift pump malfunction.



This could also indicate a restriction. The manual gives spacific instructions to test the fuel supply to the lift pump with a clear hose and a vacuum gauge.



Scott

 

[JKinney]

I just bought and installed the vulcan big line kit and moved the oem pump to the frame in front of the tank. 14. 5 idle 12 full throttle under load Oo.

 

[Thomas]

... They Me Tell There Is Nothing Wrong And Its With In Specs. But 3. 5 Psi Scares Me.

The current 24-valve Diesel Transfer Pump Diagnosis does not involve pressure readings: http://dodgeram. info/tsb/2003/14-002-03.htm

That said, it's time to replace the pump.

 

[KTobin]

Ditto on the above post's recommendation. Time to replace the pump. Under the old specs, the pump would be replaced under warrantee with numbers that low. However, DC has since changed their criteria from PSI to volume (flow) due to their overwhelming LP warrantee costs. Since you will be on the hook for a new LP, I think that you would be better served investing that money in a FASS or RASP system. I just got in under the wire with my last LP warrantee replacement so I run a pusher. I will run a complete aftermarket system if and when my stock LP packs it in again.



Kevin

 

[mhenon]

You want to see something "really" scary... check out these number on my newly installed in-tank pump;

Idle..... 7psi

cruise. . 4psi

WOT... . 1-2psi

I called the dealer that did the install (they did a good job by the way) and they didn't like those numbers either. We're working on a solution. Got a feeling DC is gonna say it's running fine. If thst's the case. . I'm thinking of putting the OEM LP back on and run it in series with the in-tank pump. I just don't think those pressures are going to keep they VP44 alive for long.

Mike

 

[jeepit]

You want to see something "really" scary... check out these number on my newly installed in-tank pump;

Idle..... 7psi

cruise. . 4psi

WOT... . 1-2psi

I called the dealer that did the install (they did a good job by the way) and they didn't like those numbers either. We're working on a solution. Got a feeling DC is gonna say it's running fine. If thst's the case. . I'm thinking of putting the OEM LP back on and run it in series with the in-tank pump. I just don't think those pressures are going to keep they VP44 alive for long.

Mike

mhenon, Have you come up with any solution with dealer yet??

 

[Tom W]

I wish someone could explain something to me. If the injection pump can operate at zero pressure it must provide some suction. I think this is so because some have found out when they change filters the lift pump is not working. Therefore, could it not be said that a strong injection pump could provide more suction and pull down the the line pressure and a weak injection pump would not pull down as much. In a hypothetical situation where you had one pump pulling and another pump pushing could you not have zero pressure between the pumps and yet have a lot of fuel flowing? Maybe a flow test is better than a pressure test. Just something to think about.

 

[mhenon]

Bosch say the VP44 will work fine even with slight negative pressure and needs no lift pump. In the Cummins/pick-up configuration though it hasn't worked out for everyone. If this were a marine application, with the fuel tank(s) typically above the engine, there might be few problems with a Cummins/VP44 combo.

There's also the fact that the LP in the Dodge/Cummins is above the fuel tank and several feet away. Look at any after market electric fuel pump and it will say "mount below fuel tank and as close as possible".

If I had this to do all over again I would have put an after market pump down by the fuel tank and installed a pressure gage (man. . was that dumb!). That would have ended most of the problems.

I haven't had a chance to take the truck back to the dealer (work) but will soon. I don't really know what they can do though. The install was done right and it's working. . low pressure or not.

I will post something here if the dealer actually makes a change.

Mike

 

[chazj]

I am 3K before I am out of warrenty. The truck just had the new in-tank fuel pump installed. My guage readings quickly hit -0- PSI w/o much effort. Am worried that pulling my 10K trailer will find 0 the normal operating pressure.



Has anyone had Chrysler extend the warrenty on the Injection Pump because of the new operating pressures? The idea that Bosch accepts 0 PSI is a new one to me; I always thought they wanted a min 7PSI.



Any feedback would be appreciated. Very hard to find accurate #'s to make my case to Chrysler as I think they should have no problem extending the warrenty if they are sure that their "fix" is the long-term correct one.

 

[jeepit]

I am 3K before I am out of warrenty. The truck just had the new in-tank fuel pump installed. My guage readings quickly hit -0- PSI w/o much effort. Am worried that pulling my 10K trailer will find 0 the normal operating pressure.



Has anyone had Chrysler extend the warrenty on the Injection Pump because of the new operating pressures? The idea that Bosch accepts 0 PSI is a new one to me; I always thought they wanted a min 7PSI.



Any feedback would be appreciated. Very hard to find accurate #'s to make my case to Chrysler as I think they should have no problem extending the warrenty if they are sure that their "fix" is the long-term correct one.

Mine reads about 7 idle, 5 cruise, 0 wot. Have been told measuring by volume not pressure is what Bosch, Cummins, and Dodge do now. I have plenty of warranty left so I am running it as is. May put bigger lines in soon. Also check out thread,"pumps, lines and what not". Good info there.

 

[RAJohnson]

chazj if you are approaching the end of your warranty coverage period, I personally would be concerned with anything below 5psi @WOT. I have replaced my OEM LP with a FASS. Plenty of pressure all the time

 

[GOT-Torque]

I've also got the Vulcan big line kit with a new Lift pump mounted on the frame rail back by the tank. I've got 15 psi idle, 13-14 cruise, 12 WOT. Couldn't be more satisfied with the Vulcan kit.

 

[Tom W]

I got a new lift pump from Cummins and mounted it back by the tank. Also new hoses and got rid of the banjo bolts. Steady 14 lbs and can't pull it down very much.