I have a 1988 F-150 4.9L 5-speed 2x4. The truck originally had dual tanks. Both tanks rusted from the inside. Last year I replaced the rear tank, tank pump, and sending unit. I removed the front tank and am not replacing. I also replaced the high pressure frame pump and frame mounted fuel filter.

Truck ran great for the past year.

Last week fuel began leaking out of the fuel lines for the front tank (they were left connected to the Dual-Function Reservoir and the tank side end was wrapped in plastic and tied up under the bed.) I removed these lines and blocked off the two ports on the Dual Function Reservoir that fed the front tank (which is no longer installed).

Yesterday, the truck was running great, then died instantly while driving. I could not restart it and had to get a tow. An hour or so later (after being towed home), the truck started and ran, however the high pressure frame pump is moaning pretty loudly.

My questions are:

Can I replace the Dual-Function Reservoir with a Single-Function Reservoir? Is the Single-Function Reservoir a direct replacement (bolt holes, fuel line connections, etc.)?

Can I remove the Dual-Function Reservoir and put these lines in place of a reservoir? Dorman Products - 800-159 or is it better to keep a reservoir in place for the pressure frame pump?

Thanks!

 

Yes you can.

Yes it is.

You need to keep the reservoir or you can experience engine surging and poor performance on hills and acceleration.

 

"SUBFORD", thanks for the response!

Is this the correct Single-Function Reservoir?

P/N: FOTZ9K044A


Thanks!

 

Looks like the mounting holes are opposite on the Single-Function Reservoir vs. the Dual-Function Reservoir. Will this pose any mounting issues?

Single-Function Reservoir
P/N: FOTZ-9K044-A



Dual-Function Reservoir
P/N: F1UZ-9B263-B

 

No it will not.
The mounting bracket has four holes in it so you can mount either one.

 

.

Thanks again for the info. Ordered the Single-Function Reservoir.

 

Some of those reservoirs have a filter in them. When they finally get plugged up the truck will do exactly what yours did. The reservoir cup may say "Non-serviceable, do not open" but they LIE!

 

Being that the Dual-Function Reservoir is 26 years old plus the fact that I am only running a single tank, I just assume replace it with a Single-Function Reservoir. I will definitely hold onto the DFR after removing it, and will open it up to inspect as well.

 

Mine ran 23 years 363 days (according to the build date) before it plugged up and that happened just after a very rough ride in a near-miss accident. I had to take the ditch to avoid a crash with other vehicles that had crashed in the road. No damage was done to my truck but I guess the ride shook loose the gunk in the tanks. I had to have fuel pumps shortly after the plugged filter discovery.
You should be fine with the SFR but do tear into the DFR and see how they work, It's a neat idea but a pi*s-poor design!

 

Thanks again for the help "subford". The Single-Function Reservoir bolted right up without any issue. I also replaced my frame pump and inline filter. Truck is running great now.

 

I disassembled the Dual-Function Reservoir. It was full of rust (from the old tanks) and one valve was sticking. I fully disassembled and cleaned it and set it on the garage shelf for possible future use.

 

Did it have a filter or was it already removed?

 

Oh, nevermind. If the valves were full of rust it obviously had no filter!

 

Correct, there was not a filter in the canister.