Engine/Transmission (1998.5 - 2002) Fuel Pressure Gauge

[madmanmanick]

I just installed a 0-30 fuel pressure gauge on my truck. During the Op-test I got 12-13 psi at idle and 7-8 psi when I accelerate. I have mounted the sending unit on the billet fuel filter cap. A friend of mine just installed one on his and also just recently had his lift pump crap out and had it replaced with another stock lift pump by a dodge delership. His gauge is reading 7-8 psi at idle and 2-3 psi when he accelerates. His sending unit recieves the fuel from a banjo fitting on the side of the fuel injection pump. Does the fact that his gauge receives its signal after the filter acount for the difference in pressure. And which of our trucks is reading the correct pressure for a stock fuel lift pump.

 

[Wiredawg]

It has been a few years since I had stock LP on my 02 w/ pre filter and aft filter FP sending units. I used to see less than a psi drop from pre and post filter. Also, mine used to idle around 13 and drop to about 8 psi full throttle. I installed a FASS 150 GPH and see 16 psi idle, and 14 psi full throttle. I use the old LP to transfer fuel from my aux tank to primary and is fine for that.



Wiredawg

 

[mhenon]

... And which of our trucks is reading the correct pressure for a stock fuel lift pump.

Probably both! LP pressures seem to be all over the place depending on who you talk to. You could check both systems with a mechanical gauge just to be sure.

Mike

 

[JCyrbok]

Do you have the intank pump or the kuft pump on the side of the engine

(or relocated)?



Did Dodge replace your buddies with the intank pump (which is likely)?



Yours sounds about right for the original carter pump located on the engine and his sound like what I have heard for the intank pump that Dodge now replaces LP's with.



Hope this helps



J-

 

[FYarcho]

It's hard to say for sure where the problem lies. But I would definately be worried about those pressures. Upgrading my fuel system was one of the first things I did, and usually the first thing I recomend to anybody. If I were you I would consider going to the big line kit from Geno's with the lift pump relocation kit. It removes all the banjo bolts moves the lift pump back closer to the tank. After I did that it made a big difference for me for stable fuel pressures.

 

[bnbrown]

the wifes 2000 with stock LP (replaced 20k ago) runs about 9psi idle, 6 running down the hiway, and 3 WOT...
my 99 with stock LP (replaced 10k ago) runs at 17psi ide, 9 WOT
both are post filter mechanical gauges

 

[WestTN]

When I replaced my lift pump I used the Vulcan re-locator kit. This allowed me to eliminate ALL the restrictive banjo fittings. While I had everything apart I added provisions to measure fuel pressure before and after the filter. If you don't do anything else, get those banjo fitting out of the system.



Having before and after pressure readings allows me to diagnose filter plugging. As a result I can safely run fuel filters until they need replacing rather than replacing on some short schedule.



Now I typically see about 14 psi before the filter and about 13 psi after. At full throttle (Smarty on #7) and boost at 25 psi I still have 12 to 13 psi going the VP44.