HOW TO: Check regulated fuel pressure, pump max output, & leakdown
With the engine off, and the fuel pump activated: 45psi at the service port could indicate a faulty fuel pressure regulator, or something else. 60psi at the fuel filter outlet could indicate a faulty fuel pump, or something else.
We also need the leakdown pressure at the service port, and at the fuel filter outlet, to make an accurate diagnosis. The article explains how to test them, and why all of the readings are necessary. Without all 4 readings, your guess is a good as mine
We also need the leakdown pressure at the service port, and at the fuel filter outlet, to make an accurate diagnosis. The article explains how to test them, and why all of the readings are necessary. Without all 4 readings, your guess is a good as mine
Pictures as promised. If this is incorrect please feel free to remove this post.
Here are all the parts you will need.

Dorman #800-121 - $7.66

1/4” MFL X 3/8” hose barb adapter from Homebrewing.org - $6.08

18” (minimum) fuel injection rated fuel line - $7.99

Fuel Injection Hose Clamps - $2.99

Here are some pictures of the assembly. It is pretty straight forward so I assume I got it right
This end goes to the pressure tester

This end goes on the output of the fuel filter

Completed assembly
Here are all the parts you will need.

Dorman #800-121 - $7.66

1/4” MFL X 3/8” hose barb adapter from Homebrewing.org - $6.08

18” (minimum) fuel injection rated fuel line - $7.99

Fuel Injection Hose Clamps - $2.99

Here are some pictures of the assembly. It is pretty straight forward so I assume I got it right
This end goes to the pressure tester

This end goes on the output of the fuel filter

Completed assembly
Last edited by Tajohns34; Apr 8, 2016 at 11:12 AM.
Perfect, thanks! I've got all the stuff to build one, but haven't got around to it yet. I built this one a few years ago and use it all the time. It connects inline at the fuel filter outlet. It's a bit more expensive, but it checks everything: regulated pressure, system leakdown, pump max output pressure & pump leakdown.

I've got another one that goes in the return line that checks for internal fuel pressure regulator leaks.

I've got another one that goes in the return line that checks for internal fuel pressure regulator leaks.
Last edited by Captain Hook; Apr 10, 2016 at 12:18 PM.
So since mine didn't work I ordered a pair of Dorman 800-086 (they come in pairs). You can also use a dorman 800-082, (straight) The 90 degree bend makes it much easier to hook up.

Same as the other. except this one fits my ACDelco fuel filter

Here it is on the filter. Make sure you pull the plastic clip out of the fitting if yours is still on the fuel filter.

Once you have everything hooked up it should look like this when connected to the pressure tester. Mine worked great

Same as the other. except this one fits my ACDelco fuel filter

Here it is on the filter. Make sure you pull the plastic clip out of the fitting if yours is still on the fuel filter.

Once you have everything hooked up it should look like this when connected to the pressure tester. Mine worked great
Last edited by Tajohns34; Apr 16, 2016 at 02:51 PM.



