yo Joe and ND,
Here is some info on that Single-Function Reservoir; "...Dual fuel pump systems must have a fuel accumulator between them. The model from BC Broncos is a multi-tasking wonder. Fuel accumulators store fuel from the low-pressure pump for the high-pressure pump. Storing fuel is a great idea for rock crawlers, as the accumulator holds a reserve of fuel, just in case gravity temporarily affects the gas tank. Accumulators also equalize fuel flow between the pumps. If one pump is pushing 72GPH and the other is only flowing 50GPH, something has to give. Once the accumulator is full, excess fuel flows out to the return fuel line, and back to the tank. This keeps the low-pressure pump from stressing the high-pressure pump. Normal accumulators stop there, but not the model from BC Broncos. They built one starting with a fuel filter. You get the accumulator and the filter all in one $70 package..."
Source: by Ryan M (Fireguy50 at fordfuelinjection.com
"...'88 Single-Function Reservoir
Used on '88-89 Broncos (& F-series/E-series/Rangers/others with single tank dual-pump EFI). In this version, the only moving part is the tank-side inlet check valve. The return ports flow freely and are NOT connected to the reservoir. The engine-side supply port is open to the reservoir.
To test it, unplug the frame fuel pump, disconnect the engine-side supply (large) line, and cycle the key. If fuel flows out of the reservoir ******, the reservoir is working normally. If not, disconnect the tank-side supply (large) line, and cycle the key. If fuel flows out of the line, the reservoir check valve is probably stuck, or its internal filter is clogged.
A reservoir marked "DO NOT REMOVE CUP" does not contain a filter. For a replacement O-ring for the cup, buy a NAPA 3268, Fram CG3862, or equivalent filter...
Fuel flows in through the larger tank-side supply ****** from the in-tank pump to
the inlet check valve, which allows it into the reservoir. As the cup fills, fuel moves up the pickup tube & out the larger engine-side supply ******. Unused fuel enters the engine-side return ******, bypasses the
blocked-off check valve ('88 revision) and exits the tank-side return ******.
The only fault that would cause a noticeable problem would be for the check valve to stick closed, blocking any fuel from entering the reservoir, but this isn't likely. With the cup removed (have a replacement cup O-ring in-hand before attempting), a sharp pick can be used to pull the valve downward & open. The valve cannot be removed from the reservoir body.
Single-Function Reservoir Testing in 88-89; "...Used on '88-89 Broncos & F-series/E-series/Rangers/others with single tank dual-pump EFI. In this version, the only moving part is the tank-side inlet check valve. The return ports flow freely and are NOT connected to the reservoir. The engine-side supply port is open to the reservoir. To test it, unplug the frame fuel pump, disconnect the engine-side supply (large) line, and cycle the key. If fuel flows out of the reservoir ******, the reservoir is working normally. If not, disconnect the tank-side supply (large) line, and cycle the key. If fuel flows out of the line, the reservoir check valve is probably stuck, or its internal filter is clogged.
by Steve83
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-- ND said "fuel at the regulator" but randomly there's something blocking fuel from getting to the rails...
If SFR check valve is ok;
So, next thAng to ck would be the rubber or steel fuel lines
Are there two fuel lines still there?
One is Supply - from tank/pumps/SFR to FPR/rail/injectors
Other is Return - from rail to FPR/tank
they are supposed to be different sized lines or hoses; but some swap in 5/8" rubber fuel hose instead.
