Make A Fuel Pressure Gauge


This page describes how to make a simple fuel pressure gauge to help diagnose and adjust your fuel pressure.  You can do this with simple hardware store parts.

Parts You Will Need

To build your fuel pressure gauge, you will need:

Quantity Part
1 0psi - 100psi pressure gauge /w 1/4" pipe fitting
1* female 1/4" to female 1/4" pipe coupling
1* 1/4" pipe to 5/16" hose barb adapter
1 5/16" hose barb brass "T" fitting
1ft + 5/16" fuel injection hose
4 5/16" fuel injection hose clamps
1 roll Teflon pipe thread tape
* If you can find one you can exchange these parts for a female 1/4" pipe to 5/16" hose barb adapter

Most of the pressure fittings and gauges can be found at your local Ace Hardware stores.  The larger ones carry a very nice selection of brass fittings and adapters.  If you can't find a few parts, try some other hardware stores.  Some larger auto parts stores carry brass fitting as well.  If worse comes to worse, look in the phone book for a shop that specializes in pressure systems.  They usually stock everything.  You can also try McMaster Carr.  The fuel injection hose and clamps can be found at most auto parts stores.  If you want to be able to see the gauge while driving, get a couple of extra feet so that the gauge can be located outside the hood the clipped to the windshield by a windshield wiper.

Putting It Together

Use the below diagram to assemble the fuel pressure gauge.  Use hose clamps at all hose connections and use Teflon pipe sealing tape at all pipe threads (look in the plumbing section of your hardware store).  Cut the length of hose so that about 3 to 6 inches goes between the fuel rail and the "T" fitting, while the rest goes between the "T" fitting and the gauge.


The gauge gets installed between the fuel supply line and the fuel rail.  When removing a fuel line, always make sure you release the fuel pressure on the system, or you will be sprayed with fuel!  You can do this by taking the cap off of the service valve on the fuel rail and pressing the valve stem in the center.  Do this with a large rag so that it doesn't spray fuel all over the manifolds.  This is not a permanent installation!  You don't want this thing hanging here when driving normally.  Do not install it on the fuel return line.  You will not get a proper reading there!

If you want a permanent fuel pressure gauge, consider an electronic unit from Autometer.  The new gauges do not require isolators to be mounted internally.

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Updated 11/11/2003.

Copyright © 1996-2003 Russ W. Knize.