Engine/Transmission (1998.5 - 2002) Lift Pump Woes

[bhutchinson]

The shop manual for my truck indicates that the fuel pressure should be a minimum of 10 psi during the "run" mode for the stock lifter pump. I don't understand how dodge can see their in-tank modification as a correct fix if the replacement pump only pushes an unsteady 7psi.

 

[DJudson]

Lift Pump

I'm just catching up with this as I've been on the road, installing my 3rd lift pump in the NAPA parking lot in Twin Falls, Idaho. I relocated the second pump to the frame rail with the Genos kit and it still failed. Pressure on the new pump was as before, 16psi idle, 12-14 (post filter) under load. Less than 1k miles, pressure begins to drop, now under load is 10. 5, idle 12 (new/clean fuel filter). I'm ready for something else.

 

[CTHunter]

I just replaced my LP in my 98. 5 due to my last one giving erratic pressure readings. Before it became erratic it would give a good 14-15 psi at idle, 10-12 on hard acceleration (post-filter). Then it started jumping around from 7 to 12 to 3 to 0 to 13 psi. So I got the latest stock pump from Cummins and it only gives a steady 10 - 11 psi at idle and drops to 8 - 9 on acceleration. Do the newer pumps not build the same pressure or do I need to take it back and exchange it? They said it had a 6 month warranty. I was just surprised not to see 15 psi at idle with the new pump. btw, I double checked with test gauge to eliminate sending unit mal-function.

 

[bhutchinson]

Voodoo, It sounds like you have a lot of experience hot rodding your truck. The dealer just installed their in-tank pump solution to my truck, and I don't think it's working right. When I start the truck, it will sit there for a full minute at 0 psi. After that it unsteadily bumps up over the next minute to 7 psi. As I drive, it bounces all over the place, up to 9, down to 5, down to 3, back up to 7, etc. It doesn't seem to matter whether I am accelerating or taking my foot off the throttle. If and when it settles down, it stays around 7 psi. I don't think I've seen it hit 10psi yet. The gauge is a brand new westach I installed two weeks ago. Does this sound like a gauge problem to you or more like a pump problem?