Engine/Transmission (1998.5 - 2002) High Fuel Pressure

[Spunkys Ram]

Why would having 7psi Carter pusher pump behind a stock lift pump cause my fuel pressure to be 28 psi at IDLE? Also is that to much pressure for the VP, and would it cause any damage? Thanks for the info

 

[Lsfarm]

pressure

The pusher pump's pressure is added to the stock lift pump's pressure. So if the pusher is actually 7 psi, and the engine mounted pump is actually 15psi, you will have 22# or so. Your pressure guage may be optimistic.



Both pumps can be better than rated so you are seeing a higher pressure than expected. I wouldn't worry about it. The only time that excess pressure is an issue is during starting, that is why the ecm just 'bumps' the pumps. Mine sees a 'bump' to about 7-10 psi, then drops to 0 till the engine starts, then I see 22-24 at idle. Been this way for 35K.



Hope this helps, Greg L

 

[Spunkys Ram]

Any info is good info. I have faith in my readings though as I took pressure with two very expensive liquid filled gauges of different brands.

 

[CstlEng]

I am still suprised that the pressure is that high. The pressure regulator (the valve that is the beginning of the return line that looks like a big banjo on the side of the VP44) should be opening before that. I don't think that you can push enough volume (with your described setup) that a properly opening regulator valve wouldn't hold things to 18 or 20 PSI.



Where are you measuring pressure? If before the filter, and the filter is loaded up, you could get the high pressures on the one side of the filter and still only get the proper pressure (or less) at the regulator.



I have never had too much pressure at the pump, I don't know if that will cause damage (doubt it as long as you don't go much higher). It might set codes or something. I'm sure others will comment

 

[**ICEMAN**]

i have a carter pusher pump on my '01 and mine idle's at 28psi. been like that since i installed it approx 2 years ago.

i read fuel pressure at the vp test port with a electric sender.

 

[Spunkys Ram]

I'm reading at the inlet to the VP with a mechanical gauge... . and the filter was just changed prior to taking the readings.

 

[DDT]

I am wanting to add a pusher too, But only have a 15LB fuel pressure gauge. Will this be a problem?

 

[ROADWARRIOR]

Yes, the 15psi gauge will be a small problem. I finally dumped my 16psi electric gauge, which was pegged. I was surprised when I found the new 30psi gauge is pegged at idle. Driving down the road it sits at 28psi. I have had the same pump setup for a few years and no problems yet.



Dan