Hey ya'll, picked up a Isspro 0-100psi fuel pressure gauge to add to collection. The directions to where to install it aren't very good. The only place i see to install it is the needle valve on the drivers side towards the front next to fuel bowl. Is this the correct place? also what am i needing to hook it up fitting/parts wise? Already have everything wired up just need to know where and what is needed to hook up the sensor. In the directions is says about using 24" of rubber hose and a needle type fitting but if you used a needle fitting something needs to compress it in order for the fuel to reach the gauge... Truck is a 97 F250 7.3, any advice or input is greatly appreciated!

 

I pulled the Schrader valve.installed a 1/8" not 90° fitting and threaded my sensor into that.

 

that Schrader valve is what i am referring too.. i had to put two 90 degree fittings (to be able to fit the sensor, i cant fit it straight out as there is not enough room tried just 1 90 degree and it wasnt far enough away from the fuel bowl) and my gauge works but its all over the place? I know the lift pumps don't maintain the same pressure for long but the readings aren't even useful. Do you have pictures on how you did yours?

 

I was able to screw the sensor directly to where the schrader valve was at. The readings dont seem to bounce around as much but it still bounces around. Any way to be able to get more steady readings?

 

This is how i have the sensor installed:

 

That's the problem with not having efuel. You will just have to kind of see the average of where it is.driving would make the needle slow from the pulsing.
Is your gauge a needle or digital?
I have an autometer gauge also so I'm not sure how they compare

 

Ah gotcha, i kinda figured thats why because of the lift pump. Its a needle gauge, its a Isspro EV2 style.

 

Also my graduations are rather large and its only quarter sweep.

 

Fuel pressure is measured at idle (40 - 80 PSI) on our trucks and fluctuates greatly. To get an idea of where your fuel pressure is, add the lowest reading to the highest reading, then divide that figure by 2. This should give you an idea of whether you're in spec or not.

As an example,
Lowest reading at idle: 50 PSI
Highest reading at idle: 70 PSI
50 + 70 = 120
120 / 2 = 60 <-- This is the number you want to be between 40 - 80 PSI.

Your fuel pressure would be approximately 60 PSI and is in the "Normal" range. If you're closer to 40 then your spring (between the schrader valve and FPR) may be wearing out. You can add a BB to increase fuel pressure, or you can purchase a "Refresh Kit" (or whatever Ford calls it) to bring the fuel pressure back to spec. Whichever method is used, check your fuel pressure again. You don't want to go above the 80 PSI mark. That could cause other fuel pressure-related issues if you do.

Back in the "old" days, we incorporated a liquid filled line with a rubber snubber between the gauge and pressure connection. This was on gas engines and even then, it didn't help much due to the use of a mechanical fuel pump, but the gauge needle did settle down a bit with this combination.

 

The mechanical fuel pump will provide pulsating pressure readings to correspond with the piston strokes. To tame these pulsations, get a $20 needle valve at a hardware store and put that between the engine and the fuel pressure gauge, or the gauge's sending unit if it's electric. After installation, close the valve and start the engine, then slowly open the valve until steady fuel pressure readings are registering on the gauge. It should not need any further adjustment for smooth and steady fuel pressure readings.

 

Sounds interesting. Would you have a picture of this setup? I understand, I think, what you wrote, but I'm unable to see it in my mind.

 

Sorry but I'm a Caveman with computers, so can't do pictures.


Word Picture This:


Get a brass hardware-store fitting to screw into the fuel pressure regulator port in order to replace the Schrader valve. This fitting should accommodate a compression-type 1/16-inch nylon tube. For the compression fitting and nylon tube, I simply bought a setup that is designed for and used for mechanical oil pressure gauges. Usually they can be bought as a package at auto part stores. This nylon tube is then extended to and installed on the needle valve. The needle valve is mounted on an L-shape bracket I attached on the firewall. Since I use an electric fuel pressure gauge, I installed the gauge's sender unit to the other side of the needle valve using brass fittings. The electric wires for the gauge are routed through the firewall. The gauge is mounted wherever desired on, below or above the dashboard. The fuel pressure readings are quick and steady and average around 50 psi for my system.

 

Interesting upgrade/install. Thank you. Reps sent.