Engine/Transmission (1998.5 - 2002) Fuel Pressure Higher At Start-up Than When at Idle. ????

[jmaji]

I have a situation here that is against the book. The Dodge manual states that my 2002 Ram stock lift pump, at start-up, is suppose to put out 7 psi. Which, understandably, is to allow the engine to start easier. After the engine is started, the pressure is to be no less than 10 psi at idle.



Welllllll, the fuel pressure in the start-up mode is 10 psi, not 7. After starting the engine I get a maximum of 8. 5 to 9 psi at idle. Driving speeds (no load)vary between 6 & 7 psi. WOT is 3-4 psi.



I changed my fuel filter when I bought the truck at 42K and now have 49K. My manual pressure gauge is connected to the fuel system with a 1/4 "ID fuel line. This connection is at the Schrader valve of the VP44. The previous owner in Canada put on 42K miles, of which 98% were highway towing miles of an unknown weight trailer. Unknown if this is the original LP. If looks could tell, it probably is.



Like other TDR members, I'm concerned about my IP. I haven't noticed any declination of power since I've owned her. I've only had the fuel pressure gauge on for the last 2K. Just before that install, I towed a 12k trailer up a 9%(+-) grade. For a stock truck, I thought she did real well. Never got below 40 mph.



I'd really like some feedback on that screwy reversal in those pressures at start-up and idle and the seemingly low operating pressure. Also, I'd like comments on my pump's operation pressure and if they are so low to cause harm to the IP.



Thanks in advance for any comments.

 

[Graphic man]

i would put a new LP in it!

With a new LP you should have around 5-7 psi key on, mine goes to 15 psi then to 5 and then the pump turns off (i have the updates done)

start up 12-15 psi and that will go up and down until the grid heater stops,

at cruz around 10-12 psi

WOT 8-10 psi



Hopes this helps!