Engine/Transmission (1998.5 - 2002) High fuel Pressure

[rkelso]

I have never posted and question before. Always tried to find my answers by reading.

I have had high fuel pressure for about two or three years now. I have a carter (GP461HP ,18 PSI, 100 GPH, ) I put it right after the fuel tank. Its all 3/8 lines with all AN 6 fittings,(fuel filter to the vp 44 with 1/8 port in between the two for mechanical fuel pressure gauge) The fuel pump is feed form the bottom of the fuel tank 3/8 AN fitting. I put in a bypass valve right after the carter pump to see if I could bring down the pressure. I got it to hold about 35 LBS for a good year or so. For some reason the last couple of months I can not keep the pressure form going to Zero when I get into the throttle. Changed the filter and turned off the by pass and still can make it drop to zero only when I get into it hard. . The pump when the by pass is turn off will get up to 60 lbs. I would sure like to know why a pump rated at 18 PSI can build up to 60 . Any advice would be great



I fulled out my profile dont know why it doesnt show

02 auto,piro,boost,trany temp,fuel pressure,cold air intake,edge comp wire taped,shift kit, western trans T. C, 4" exhaust tubo back,cool down timer,Steering stabilizer

 

[Pullintime]

what did you ever come up with on your high psi issue?

 

[Pullintime]

I'm in the process of running down an almost identical issue. 1/2 diameter 300 psi fuel line from 1/2 module drawlstraw to injection pump/ pre-screen before (2)4601Hp carter pumps ran in parallel to provide a backup and/or increased flow) started running over hundred PSI and holds 80psi from shutdown to restart. Everything else is exactly as you'd like to see...

 

[NIsaacs]

I would say your fuel pressure sending unit is bad.

Nick

 

[Joe Mc]

From what I've heard here (and there are many variants) the VP doesn't like a head (LP) pressure of more than 25#. Also, if you have less than 10# @ WOT or any other throttle position that's not good for the VP. I'm not sure how any of the pumps mentioned above could produce the kind of pressures indicated? I've been using an aftermarket (Walbro) system with a regulator which I have set at 20# for years (this particular pump can make up to 90# unregulated), I see no increase or decrease at any throttle position. I suggest connecting a mechanical 0-30# gage with a hose long enough to tape on your windshield and go for a test/comparison drive to see what is really going on.

 

[Bob4x4]

I'm in the process of running down an almost identical issue. 1/2 diameter 300 psi fuel line from 1/2 module drawlstraw to injection pump/ pre-screen before (2)4601Hp carter pumps ran in parallel to provide a backup and/or increased flow) started running over hundred PSI and holds 80psi from shutdown to restart. Everything else is exactly as you'd like to see...

A Vp truck will not start at with high fuel pressure,verify your fuel pressure gauge before trying to fix a high pressure issue

 

[Pullintime]

Kool... I installed a mechanical gage, long before I did anything, to verify the vp was getting fuel.
Everything is doing a good job. Pulls hard, all other gages are right on time, and there is no coolant in the oil or oil in the coolant.