ymeski56

To the left/ drivers side/ under dash

1987 F-150 XLT 4x4

[quote=ymeski56;500604] Pressing the inertia switch did not make a difference, thanks anyway!

I hear a whirring sound from each in-tank fuel pump, but no fuel will pump out of the dual function reservoir discharge/outlet…

I need to disconnect the inlet of the dual function reservoir, and switch front & rear in-tank pumps to determine if either is pumping.


THINK ABOUT THIS!

15 minutes before my problem started:

I switched from the rear ¼ full fuel tank to the front fuel tank and it was less than ½ full of fuel.

COULD THIS BE WHAT CAUSED MY NO START PROBLEM?

Everything points to the Dual Function Reservoir as being the problem.
Am I over thinking this?

It takes some pressure (2-3 psi. or so) to operate the dual function reservoir and perhaps by switching to a fuel tank that was not full… the pressure was not enough to make the dual function reservoir switch as designed?

I read somewhere years ago: 1980-up F-Series trucks with dual fuel tanks should not be switched unless the fuel tank being switched to was full of fuel.

Does anyone else remember hearing or reading about this?

It would be odd or rare for both in-tank fuel pumps to quit pumping at the same time, right?

Thank you all for thinking about this no start, because of no fuel problem!

chelios

[quote=1987 F-150 XLT 4x4;500689]
i switch from tank to tank, both, or only one, almost empty or full. no problems

ymeski56

[quote=1987 F-150 XLT 4x4;500689]Jack (Daniels) say's you're welcome!!!

1987 F-150 XLT 4x4

THANKS for the humorous reply! ^

I will keep checking.

Today, I will add fuel to each tank to bring them both up to full to see if that makes a difference.

I will then disconnect the inlet to the dual function reservoir to see if either in-tank pump is actually pumping.

If they are pumping, I will know my problem is in or with the dual function reservoir.

Thanks again

ymeski56

Dyslexia is sometimes hard to discern from a polish heritage. I'm experienced in both.
Anyway.Here's what raises my suspicion:
1.% of possibility both went simultaneously is low.
2.A common denominator has been IDed, further promoting premise 1.
Here lies the rub!
3. Checking individual tank pump output would further promote premise 1. & 2.
4. Filling both tanks would discount premise 1. & 2. completely, & demand removal of truck bed
if in fact premise 1. & 2. is successfully discounted.

This will lend 1 of 2 descriptive phrases applicable you may choose from:
A. "I fear my shoes have wet themselves by my profuse pissing upwind!" or.
B. 'I have shot myself in the foot. No more tap dancing lessons, or open toed shoes!"
Simply put, your makeing a big bet on a long shot, instead of a small bet on a favorite!

Check tank pump outputs before filling both tanks solely for the purpose of proving the pump are bad.
If I were you, I'd study the link I provided you w/ the selector valve disassembled, & attempt to return function to it. Manipulating the function by back & forward pressuring the valve with an air compressor hose. If you are successful, it won't mean it's fixed, only that it was the problem & needs to be rebuilt or replaced. Normally an O ring has disintegrated & jammed mechanical function, or multiple seals have swelled, jamming function, or in this case, diaphram failure also!
"Think w/ you dipstick Jimmy!".......WACK!!!!!!

hackersmovie

Fuel level in either tank will make NO difference. I continually switch between empy and full, 1/2 full and empty, full and full, any combo of fuel levels, and nothing happens, truck runs great, Bob's your Uncle. I even switch while running 60-70mph down the highway, no issues.

You can safely rule out, fuel level.

ymeski56

"Bob's your uncle"?

1987 F-150 XLT 4x4

__________________________________________________ ____

ENGINE is running now!

IT IS FIXED!

I filled both tanks with gas this morning, then
I sprayed Starting Fluid into the air intake, turned the key to start the
engine, it started right up, I continued spraying and revving the engine until pressure
read on the pressure gauge.
I backed down the engine and it idled down normally, I let it run while I cleaned tools.

I drove the truck on an out-of-the-way road, ran through the gears 3-4 times at full throttle and no problems, the engine performed normally, drove home & parked with the engine still idling smoothly, turned off engine, started engine 4 more times and no problems!
__________________________________________________ _______________


I THINK…

The High-Pressure Fuel Pump pulled a vacuum and sucked out the fuel from the
Dual Function Reservoir (DFR) and emptied the fuel lines of fuel.

Because if the ports in the DFR are not lined up to let fuel pump through as designed,
the low-pressure in tank fuel pumps cannot pump fuel through the DFR and that’s when the engine starves of fuel.
(When I removed the old fuel filter & the high-pressure fuel pump, both were nearly empty, there was very little gas in them.

I had switched to the less than 1/2 tank of fuel and drove 6 miles before the engine quit.

Again, it seems to have something to do with the inside of the 1987-89 F-150 only
Dual Function Reservoir, because no fuel would pump out of the DFR outlet to the high-pressure pump suction, until I re-connected all the fuel lines and filled both tanks with fuel and started the engine with starting fluid, only then did the fuel system become pressurized through the DFR and on to the injectors on the fuel rail.

I could have filled just one tank and the DFR would have started working as designed; once I sprayed the starting fluid to get the engine running, only then did the fuel system get primed again and show pressure at the schrader valve.

The above scenario is my only logical idea of what caused the No Start Problem!

I have switched fuel tanks in the past while driving also, but
I always had a full tank to switch to, but last week, the tank I switched to had less than ½ tank for some reason…

This information only applies to 1987-89 F-Series trucks with dual fuel tanks.

Thank you all for your replies!

hackersmovie

Google it.

OR

From wikipedia:

Typically, someone says it to conclude a set of simple instructions to mean, "and there you have it," or "you're all set." For example, "To make a ham sandwich, just put a piece of ham between two slices of buttered bread, and Bob's your uncle."