NCTURBOS

So I just installed a FP guage on my truck last night... The VP44 and lift pump were replaced approx. 20k miles ago under the previous ownership, and the dealership installed the relocated LP.

The truck has just under 10psi @ idle and when you stab the throttle in park/neutral it drops to pretty much 0 psi. There are no codes yet. When you prime the pump w/o starting the truck it has just above 10psi.

The first (2) things I'm going to do... Try another guage as this one is an older 0-100psi Autometer, and replace the fuel filter. Where is the best place to get a 0-30psi 2-5/8 mechanical guage?? Autometer's site doesn't list one.

I guess then the truck will sit until I get a good LP set-up. I'm leaning towards the mechanical pump that Opie has.

Thoughts?? Probably a good thing the Redline box isn't installed yet.


K.

Doug_TX

Several vendors on here sell mechanical gauges. I'm not sure Autometer sells mechanicals, but ISSPro and DiPricol do and they're good instruments.

Just 'stabbing the throttle' at idle might not be representative of what your FP is actually doing. If you make an instant demand on the fuel supply it will surely drop. It will take the pump a period of time to catch up to the demand. But 10 psi at idle is definitely on the low side. Try a Holley Blue (get them at AutoZone for less than $100) and a Vulcan big line kit. That's probably what I'll do once I get gauges installed.

wcbcruzer

Did you bleed the fuel hose before plugging it into the gauge? Are you running an isolator?

12valve

you cant really see such low pressurew with a 100 pis guage...

get a 30 psi

mine shows 27 at idle, and 18 minimum at wot with the drag comp on 5x5

thats with a Holley blue, inline with the stock lp i have 70 bucks into it

NCTURBOS

I stole the 0-100psi guage off one of the Buicks, for which I need a guage that reads past 70psi as FP rises with boost. The guage reads in increments of '10' but yes how accurate is it at that low of psi... I'm not sure??

I have the guage currently attached at the test port of the VP44, running through 4' of braided line up under the hood to the windshield where I can see it outside the truck. It's not permanent, but is pretty nice for test purposes.

The truck is not a daily driver, and I don't plan on making it a "race" truck. More for playing with and occassionally plulling the Buick(s) to an event. I do plan on making as much power as possible though... without losing drivability!!


K.

Ram1999

It's an "old" 100 pound guage trying to read 10 PSI accurately.

DO NOT trust that gauge.

As said above, get 30# mechanical.

I bought a 30# ISSPRO HERE for $39.

Ph4tty

http://www.vulcanperformance.com/

Another thing to consider is a line kit from the above vendor. He has setups for the in tank pumps like yours. Basically this will increase the volume of fuel in the lines so the pressure won't drop as quickly. He also has fittings to run a different pump than the one dodge installed. Not much $$ required

The mechanical pump is of course the ultimate solution. I want to go with the f-1 cam with f-1 fuel system, but am running a vulcan kit for now and it works great

wcbcruzer

Ah man, I just got a 0-100 psi gauge. I really wanted a 0-60 psi one for better accuracy but I'm running Autometer Ultralite gauges and I couldn't find a 0-60. So you guys are saying the 0-100 psi gauges aren't as accurate?

NCTURBOS

IMHO... I compare the accuracy of the guage similar to that of a torque wrench. The top & bottom 10% aren't as accurate as the middle 80% of the guage.


K.

cluckmaster

Jumpin in - I've got DiPricol Optix guages and was hoping to get a matching fuel pressure gauge, but they only have a 30 and 100 psi gauge. Should I look into another brand for a 40 or 60 psi?

Doug_TX

The 30 psi gauge would be the one you want. There's a pressure relief in the VP-44 that won't allow you to build up much past there. If you are consistently over 30 psi you have a problem with the return valve. A lot of folks are running 0 - 16 psi gauges and they work okay for the most part. But a 30 psi gauge is what you want.

greasemonki

1 psi on a 100 psi gauge is only 1%, so I would agree, use a small increment gauge. Even if the gauge is off by 3%, that leaves a large 7-13psi range at idle.

DL1221

Cluck you have a 97 12-valve right? Then you need at least a 60psi gauge. Don't use a 30, you'll max it out.

30psi gauges are good for 24-valvers, but 12-valvers need at least a 40psi gauge, or even better a 60psi.

Here are the factory fuel pressure specs for a 12-valve:
17-22psi at idle
25-35psi at 2500 RPM no load.

NCTURBOS

Just ordered it. I also checked out Autometer's 2-1/16 mechanical FP guages, they want $200.00 plus for those things on Summit Racing's website!!


K.

NCTURBOS

Is there anymore info on the F-1 fuel system? I checked the website but they only mention their injectors.


K.