I have a similar problem. Fuel was going from my rear tank to my front. I eliminated the front tank and joined the two lines together with a short hose.(saw that somewhere online) Truck ran great for a week or two. Then it started sounding it like it was running out of gas. Spitting and sputtering. It would shut off then would start up again, then go a little and shut off. Now i cant get it running at all. On a another note the rear tank would not take gas and its not ful, but there is gas in it. I would try to fill it and it would just blow back out at me. I dont no what to think. Any help would be great.
Hey guys, I've been reading posts here for quite a while and I appreciate all of the information. I have the problem described here and in many other posts about the fuel problems. How would I qualify for the FTEpartsguy.com discount? This price is excelent for that 6 port valve I need, I just hope they still stock it. I've recently replaced the tank, sender unit and 2 of the 3 fuel pumps. For now I'm going to try ignoring the back tank, but I want to keep it there incase I decide to use it for emergencies even if it's just as a storage tank to siphon from. I also installed a brand new Edelbrock 4 barrel carb and really want to fire up my 460 and hear the exhaust rumble out of my dual glass packs.
Anyway look forward to any responses here and thanks again for all the knowledge sharing.
You float more than likely has sunk and does not float anymore.
To test the gauge:
Unplug the wiring going to the tank.
Turn on the key with the rear tank selected.
Note where the gauge points too (pegged full).
Short the wire with the yellow on it to ground (pegged empty).
If the gauge swings to the other end of the scale then the gauge is good and the sender in the tank is bad.
This diagram gauge wiring should be close to what you have, disregard the in-tank pumps:
i've got an 85 F150 with the carbureted 351 HO, just replaced the fuel pump, and the truck ran great after i blew through the lines and primed the pump. but the past couple days it has died on me in regular driving, much like i ran out of gas, but it is reading at about half tank.
just out of curiosity, i was wondering what size the nylon line is and if i could bypass the selector switch and just run off of the front tank. also the rear seems to empty itself but has no visible leaks or holes, any ideas there?
well, i figured out the issue, seems that the selector valve is bad, and since it would not get power, it would revert to the (empty) rear tank, so in a fit of MacGyver, i just redid the lines so that the front is coming in where the rear was, and vice versa, granted i had to mount the valve vertically to avoid crimping the nylon lines and leave the selector valve disconnected from power (the tank levels still read correctly though in case anyone is wondering). but it has been running perfectly ever since!
Back to the 1985 diesel: I know the gauge itself is ok because when the front tank is selected it works about right. Seems like it must either be a float issue in the rear tank or a wiring issue between the tank and the selector valve switch in your diagram.
Hello All, after reading this thread slowly and carefully, I have thought of another solution to the dual tank selector valve/fuel guage problems that plague this series of Ford Trucks.
But first my problem: Fuel guage does not work on one tank, and only very occassionally on the other tank. It seems one tank is always fuller and both tanks are not reliable when estimating Miles To Empty. Here in Texas, I need a Fuel Gauge!
My first idea to a solution: Replace the Fuel Tank Selector Valve with an aftermarket Pollack valve...The one Ibought has no return ports. Then I could just cap off the return lines to the tank. Also, I could do away with the return line from the motor (SINCE MY TRUCK IS CARBUERATED). YES, IT'S CARBUERATED!
WHY would FORD put such a RUEB GOLDBERG system on this truck...other than to only use existing parts off their shelves...knowing they would rake in the huge bucks on replacement parts---does this sound about right?
My second idea to a solution (after reading this thread): Replace the Dual Fuel Tank Selector Valve with two Single Tank Reservoirs from "86-89" Bronco/II thereby only slightly modifying the routing of the 6 lines and eliminating the problems of crossfilling, valve malfunctions, etc. I can make a bracket to mount the two single tank reservoirs side by side off the frame.
I think my second idea will fix all the problems associated with the dual reservoir system AND it will also aide in troubleshooting problems with tanks, sending units, in-tank fuel pumps, tank selector switch & wiring problem identification. WHAT DO YOU ALL THINK OF IDEA #2 ?
I will check this in a few days for any ideas/problems/suggestions that this forums members can see/shoot holes in the second idea to a solution.
Thanks for a great knowledge base, isn't the internet great!
We have a 1986 Ford E350 motorhome with a 460 in it. This is the model that has a carb and an electric fuel pump in each of the two tanks. The pumps are fed power when the starting solenoid is engaged but once the starter drops out so do the fuel pumps. I have hot wired the wire feeding the pumps off the solenoid and whenever I turn on the switch to feed the pumps this way they work fine and the engine runs with no problem. Will it harm the system running the pumps this way or where would I look for an electrical problem that supplies power to these pumps while the engine is running and not cranking. Does anyone have a wiring diagram for this model or know where I can buy one.
By the way it is called a "Dual Function Reservoir" - 9B263 (base part number) and not a "selector valve". The "Dual Function Reservoir" is not electrically powered, it operates off the fuel pressure of the running fuel pump.
There's no "real" selector valve on 1990-1996 trucks. The older 1987-1989 and 1986 5.0L EFI trucks have a dual function reservoir mounted on the frame rail that acts like a selector valve. The Carbonated trucks 1985 and earlier 5.0L and 1987 and below 4.9L, 5.8L and 7.5L have a 6-way mechanical valve. The switch on your dash selects which fuel pump will be energized.
I have a 1987 F150 with 4.9 I-6. The Previous owner performed an abortion on the fuel system. Only the front tank functions, the gauge doesn't work, the lines are disconnected, I suffer heat soak / vapor lock, and my injectors are really dirty upon inspection. (although it ran good except for the vapor lock)
The gasoline that came our of the filter was literally black!
I am looking for two things here, a part number / source, and an opinion of fuel tank cleaning.
Basically I have everything apart and want to run new metal fuel lines between the tanks and selector switch. I will build these with steel line and double flare fittings.
I have spend days searching for is a 6 port valve that I can connect between my low pressure tank pumps and my high pressure frame rail mounted pump.
A 6 port valve that will control regualtor return flow to the appropriate pump.
I'm willing to do whatever wiring and plumbing (including double flaring my fuel lines) that may be necessary. Does anyone know of a 6 port valve and where to find one?
Lastly, because the fuel from my filter being black, would you recomend that I drop and flush both tanks?
I appreciate your response, looking at your past posts, you are very knowledgeable on this subject.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
I do have the two electric pumps, one in each tank.<o></o>
Applying power directly to the terminals on the tank for the front system produces no pressure. There is no current draw so I either have an open or the pump is otherwise bad. <o></o>
I can only assume the rear pump is bad too.
I think at one time I used to have the reservoir switch but it was removed by the PO.<o></o>
Short of visiting the nice folks at Lawley Ford in beautiful downtown Sierra Vista, has anyone come up with a common parts modification that actually works? <o></o>
Just came from my friendly Ford dealership.
I explained the situation to the parts guy and felt a little uncomfortable when he replied with "I wasn't even driving in 1987".
He said he can get the part from Sacramento. It'll take 7 days and cost $297 American money.<O</O
I told him it is frustrating when you have an excellent vehicle but can't get parts. He said I shouldn't expect for find parts for anything over 12 years old.
When I asked about the intake manifold / fuel rail heat shield Ford devised to stop heat soak / vapor lock on the 4.9's, he said it is obsolete and unavailable. He suggested a salvage yard about 90 miles away.
What's a guy to do...
Has anyone tried using a pair of 3 port fuel valves, both wired to the original factory dash switch, with four wires, two going to each valve? One valve to control the fuel from the tanks to the rail, the other from the rail to the tanks.