Dual fuel tanks, manual fuel pump-no electric
 

Hello,


Have a 1985, F250HD, 460ci with dual fuel tanks. These tanks are now electric fuel pump. I would like to convert to manual fuel pump. I don't think adding a manual fuel pump would be difficult but how would I make the switch from the side tank to the rear tank if I'm not using the fuel selector unit or the electric fuel pumps? I would like an all manual, non electric option for swapping fuel tanks


Thanks,


nonrev

The early trucks in this series, up to around '84, used a simple valve to switch between tanks. It was controlled by a single wire and had 3 fittings - one for each tank and one for the fuel pump. And the fittings took a hose.

Instead, yours switches based on the pressure from the in-tank pumps, and the connections include returns to the tank. And, it uses plastic lines with special fittings. It is a complex setup and when it doesn't work right it can cause odd problems like pumping out of one tank and returning to another.

To convert will take some wiring changes, and changing from the plastic line to hose at the solenoid. I haven't done it but it shouldn't be too bad.

What are you going to do when on a hot day it stalls out and won't run? Ford put that system on there for a reason. Like everything else, some people have problems and some people don't with vapor lock. But that's why Ford put it on there. Why only on the 460's, I can't explain that either. I have a couple of theories but no hard evidence for any Ford documents.

Interested in theories
 

Hello,


I'd be interested in your theories... I have heard people talk about the fuel lines being run to close to the exhaust and heat causing the issues. Anything to that U think?

Well on these trucks, the stock exhaust runs on the pass side, the fuel lines run on the driver's side.

One of my theories was a lot of the 460 vehicles were service vehicles that sat around and idled all the time, and on a hot day that might cause a problem. They also probably do a lot of pulling at low speeds which would cause heat on a hot day. But that's just ideas I made up, I don't know the real reason. I do know a lot of people have gotten rid of the original system, but we have had some guys with RV's who have had vapor lock problems with their Ford chassis with the 460 engine in it.

Yes, the fuel lines run down opposite frame members, so that heat isn't likely to be the problem. One of my theories is the larger engine in the same sized engine compartment causing more heat. But I can subscribe to Jim's theories as well. In any event, you may have vapor lock problems and should consider that before making any changes. As long as your system is working I don't think I would change.

solutions
 

Thanks. Both the side tank and the rear tank were full of corrosion. I replaced the side tank and pump/sending unit and now it runs of but on the side tank only.


Just ordered the 38 Gal expanded tank to place in the rear. I figured the Valve Ass'y was probably full of gunk so ordered the Valve ass'y E3TZ 9189-C (only 15 left in FORD OEM inventory according to the girl at my local Ford) and have been wrecking my brain for a pump/sending unit for the rear tank, FORD E5TZ 9H307-FA or Motorcraft PFS-130. None to be found anywhere. I did find a pump/sending unit at LMC Truck, P/N 43-4044, don't know if it will work or not.

But the larger problem seems to be what to do when these systems need replacement and/or parts... they just aren't to be found anymore.


I was looking at some earlier models (1984 I think) and they seemed simpler, only having a 3 way Ass'y. Have kicked over the idea of eventually trying to redo the entire fuel delivery system but don't have any ideas yet.


Think I'll start another thread on replacing the Fuel deliver system on these trucks and see if anyone has some good ideas


Thanks

I have to agree with the Vapor Lock comments.....I ended up having to install a 6v electric fuel pump inline with a separate switch on My '49 Desoto Inline 6 even after having a larger radiator built due to hot summer temps and low RPM's.

My truck hasn't vapor locked in 28 years. ?...?

If you're concerned I'd suggest putting a reflective insulating sleeve on the hard line from the pump up to the carburetor. (where it passes the #5 exhaust manifold)

The 6 port switching valve is available, or you can just use the Pollack valve the diesel guys use.

The hot fuel trucks don't switch via pump pressure, they have the same switching valve the diesels do.
For the rear tank, you could use an 87-up sender. Physically they are the same, only the guage sending unit is reversed, so the guage will read backwards.
On my truck I have eliminated the in tank pumps and run an aftermarket electric on the framerail. I also ditched the return line(it is capped off,) but still have the 6 port valve in place.

E5TZ-9H307-FA (replaced E5TZ-9H307-F) .. Fuel Tank Sending Unit & Pump Assy (Motorcraft PFS-130) / Obsolete ~ No Ford dealer or obsolete parts vendor has any.

Applications: 1985/86 F250/350 460 with aft axle steel fuel tank. If the aft axle tank is plastic, it uses a different sending unit/pump.

E3TZ-9189-C has an MSRP of $399.65. How much did you pay for it?

In reply to f100swb;
If the sender is new I'd imagine you could simply solder the sender wire to the opposite end of the circuit board and have it read correctly for a pre'87 truck.
(it's still 10-70 ohms....)

I now have a pair of new senders for mine and am trying to find the time to pull the bed and install them.

According to this it's not exactly the same but reversed. They are a little different in value, might make it not read correctly at the very end of the scale. Check this link.

Universal Fuel Sender Questions & Troubleshooting

When I first got my truck I started a thread along the lines of this one. I posted a link to a 6-port mechanical valve. https://www.ford-trucks.com/forums/1...l#post13014736

I never went forward with it as after I installed my 38 gal tank it turned out the electrical selector valve was ok, though recently the used pump I installed in the new rear tank recently crapped out completely, after being weak for a while. Under heavy load it wasn't providing enough fuel and the engine would stumble.