Shimming the fpr from 48 psi, how much shimming.

[FreeFlyFreak]

Hi again.

Today I cleaned my fpr screen, it was filthy, covered in what seemed to be a fiberous material.

I just got my fuel pressure guage and am showing 48 psi at the schrader valve.

I have some questions:

1) In your experience how much do I need to shim to get from 48psi up to recommended pressure.

2) What is the recommended pressure and recommended by who?.

3) In your experience what is best to use, bb, screw, rivet, washer?

4) Had the spring out today to have a look. How do you get the silver part out of the housing, does it just pullout with some needle nose pliers?

I must be able to change the shimming easily. I will want to put it back to stock when I get my new fuel pump next week, and then reshim as I guess a new pump may have better pressure. But for now I just want to shim it as is to see the effect.

Thanks

[Quadzilla]

When I shimmed mine, I used a #2 allen head screw, because I thought it would be easier to keep the spring centered, and also keep it from kinking. The bb is probably the easiest way, but doesn't leave any way to adjust the pressure.
I started with a #2 screw, and found that it didn't raise the pressure enough, so I added a nylon washer to the screw before putting it into the spring, and that brought my pressure up to about 70psi. I tried a second washer, but that made my idle lumpy, so I removed the second one.
I understand that most don't see any improvement after the pressure is up to 65-70psi. 75psi isn't noticeably better. 80-85psi would be considered the upper limit, since anything higher puts undue stress on the fuel pump.
If you want to get the little silver cup out, needle nose pliers, or a magnet work well.
Happy shimming!!

[FreeFlyFreak]

OK thanks.

I just finished it, I couldnt find a screw at the hardware store near me to fit, but they did have a BB that was perfect, so that is what I used.

The BB is not adjustable like a screw would be but it worked just fine, I am at about 60psi right now, actually 58-63 with the ocillations but that was on a cold engine. I think it may come up a bit as the engine warms up and the spring expands? Anyway it does idle quieter and it is is at the top of the range that ford recommends now.

I was shooting for 65psi but I think I may well be there on a warm engine when I put my new fuel pump in.
I have a leak in the valley and am going to pull every thing out and fix it, change the pump, replace the flexible hoses, replace the bajo bolt washers, and clean and check the filter bowl while I have it out.....
Anything else I need to check or replace while I have everything out of the valley next week?

[Patrick Feeley]

Take a good hard look at the condition of the small wiring harness that runs around the fuel bowl. The insulation like to get mushy on the wires when exposed to fuel. Cheers!

[Paul H]

Yea what Patrick said!!

The wires going through the pastic harness cover to the IPR is the worst about it. The fuel will eat up the back of the plug for the IPR too. Could cause the IPR to act funny or all sorts of goofy idle problems.

[greenskeeper79]

Anybody have pics or a link for instructions on how to do this, might have to try it out on the truck since it hasn't been done yet. Thanks!