Engine/Transmission (1998.5 - 2002) fuel pressure

[TheDodgeMan69]

I have on 01 D2500 and i in stalled a fuel pressure gauge and it showed 8 psi at an idle and 2 psi when I got on it. My friend said my transfer pump was bad. So I replaced it with a stock pump and it only shows 10 psi at idle. Is 10 psi normal? I heard from several people that the pressure shouldn't be lower than 12 psi. Any ideas?

 

[Missouri Mule]

14 psi to 16 psi at idle is ideal should go up when you rev engine. I have read no less than 5 psi at wot.

Squeeze your rubber retrun line see if pressure goes up if it does than your overflow valve is bad. If it doesn't go up your new pump is weak.

 

[TheDodgeMan69]

Could a dirty fuel filter cause low fuel pressure? Driving the truck for a week now. The highest pressure is 11psi. Still 10 at idle and at highway speed. I will try piching the hose and report back.

 

[SHobbs]

Stock L. P I get 12psi at idle, around 10 at highway speeds and usualy never below 7 at WOT. My pressure is measured after the filter and a drop in pressure is what I go by as far as the filter. I know a fresh filter gives me 12psi and when it drops to around 10 at idle and 5 or below at WOT then I change it. The stock L. P pressures vary with every pump some I have had 10 at idle and never below 6 at WOT. Best thing is to have a fresh filter and see what your pressure is.



If you have not done it yet I suggest relocating the pump to the frame rail, it really helps with the WOT pressure it did on mine. It also helps the longevity of the pump being that it is happier as a pusher rather than a puller.

 

[Koa Man]

What kind of FP gauge are you using? If it is one that uses an isolator, check the antifreeze. Insufficient amount of antifreeze in the isolator will give you low pressure reading.

 

[VHolloway]

I have a fass I get 20 psi before filter 19 after filer at idle on the open road 17 to 18

wideopen 15 to 16 allways starts rite up. but i don't start it like a gasser like most do

 

[John - K5AWO]

Stock L. P I get 12psi at idle, around 10 at highway speeds and usualy never below 7 at WOT. My pressure is measured after the filter and a drop in pressure is what I go by as far as the filter. I know a fresh filter gives me 12psi and when it drops to around 10 at idle and 5 or below at WOT then I change it. The stock L. P pressures vary with every pump some I have had 10 at idle and never below 6 at WOT. Best thing is to have a fresh filter and see what your pressure is.

If you have not done it yet I suggest relocating the pump to the frame rail, it really helps with the WOT pressure it did on mine. It also helps the longevity of the pump being that it is happier as a pusher rather than a puller.

My pump is stock on the engine, and I concur with what SHobbs says here.

Been meaning to put that pump on the frame rail now for 5 years. One of these days :-laf

 

[WestTN]

Put a Vulcan Big Line kit on. It will replace the horribly restrictive banjo fittings. I doubt you will see a pressure drop over 1 psi under the same conditions you stated.

 

[TheDodgeMan69]

I am useing a ISS PRO gauge w/out an isolator. I bled the line several times to get all air out of the line. Now The pressure is down to allmost 8 psi going down the road. 11 psi at an idle. Havent changed the filter yet. Could the replacement pump be going out allready?

 

[SHobbs]

Dennis,



Yes sir, AN fittings and 3/8" or 1/2" line helps alot.

 

[RCrosby]

vulcan 1/2" lines all the way, call there shop they will help you, I have the fass ddrp pump near tank with 1/2" lines. 14-16 psi. stock engine. if you are planning to put more power on that engine. you may need a bigger fass pump. your injector vp-44 pump needs fuel. or the vp-44 will go down hill. good luck

 

[TheDodgeMan69]

l changed the filter and the pressure went up to 11 psi at an idoland 10 psi goin down the road. Thanks for the help.

 

[ALepley]

Get rid of the that stock lift pump asap. Put a fass or air dog system on. Its the best investment you can do for your truck. $400 for an fass or $1700 for a vp its your choice.