Fuel issue

[2trux]

I'm working on an 88 ranger. It seems to be suffering from fuel pressure issues after driving for a short time, (intermittent issue of course), I have replaced both fuel pumps and checked the wiring. One strange thing I noticed is on the canister thing that is is between the tank and the high pressure pump the fuel supply line connects to the top fitting on one side and the bottom fitting on the other. Of course the return is just the opposite. Is this correct or has someone flipped one of those lines? I bought this as a non-running truck.

Thanks

 

[Uncle Gump]

The canister thing has a fuel filter in it. Have you changed it?

I also thought the lines were different sizes and couldn't be connected wrong.

But I believe if they were wrong... the return line would now be the pressure line and it wouldn't run at all.

 

[2trux]

No I have not changed the filter in it. I tried once to remove the bottom and it wouldn't budge. I guess I will remove it and try again.
It also seems interesting that they have the return line go through the filter and not just bypass it like the front filter.

 

[Paulos]

It is my understanding that they stopped putting the filters in the fuel reservoirs after '87. That configuration on the reservoir is correct. The connectors are not changeable, so small connectors are return, larger connectors are supply/pressure.

 

[RonD]

Yes, that can just be a reservoir and no filter inside, so cap is GLUED on and will break if you try to remove it

Yes, there are 4 lines on the canister they are different sizes so will only go on one way

Return line just passes thru the top of canister, it is in that configuration from the days of DUAL gas tanks
Single gas tank wouldn't need that setup but with dual gas tank option it could be added easier if Return was on the canister so it could be switched as well as IN hose

Dual tank canister seen here: https://www.ford-trucks.com/forums/attachment.php?attachmentid=202590&d=1501296008


As for the fuel pressure issue, there is a Fuel Pressure Regulator(FPR) on the engine, its connected to the Return line

You don't mention testing the fuel pressure?
Should be 30-40psi with engine running
And should stay above 30psi when you hold engine at steady 2,500rpm

And with key off pressure should hold above 20psi for a few MONTHS

 

[2trux]

I got the reservoir off and removed the bottom without breaking it, ( that sucker was on hard). There was no filter.
I did spot a piston wrapped with a spring in the inlet side. It was just rattling around and if it got in the right position it shut off flow from the inlet.
I drilled it out and there is nothing now to restrict the fuel in that piece. Only time will tell but I have a good feeling that this was my problem.

I have attached 3 pics showing the valve with the piston in, after being drilled out, and the part I pulled out.

 

[2trux]

@RonD When the truck is running right the fuel pressure sits around 32 running and 40 when key is first turned on. When it sputters the fuel pressure has dropped to 20 or less. I believe that is due to the restriction described above.