I just purchased an 84 f250 with a 460 with dual tanks. I bought the truck from a widow. It had sat for 6 yrs in a garage. Her son and a mechanic replaced the rear tank, and put new fuel pumps in both. They installed a toggle switch on the dash to switch tanks. I have only had it for 5 days now. When I switch to the front tank, the fuel gauge does not work, and the engine gets no fuel.

I would appreciate any thoughts on a logical way to investigate this.

Thanks, j66b

 

I could be wrong, but I didn't think the '84s had in-tank fuel pumps. I know that my '85 F-250 with a 351 had a single mechanical pump on the left front of the engine.

If it does have in-tank pumps, see if you are getting power to the pump in the front tank. If you are, it's the pump. If not, start tracing back.

If it doesn't have in-tank pumps, then it's either the switching valve or a plugged gas line.

 

With factory installed mid-ship and aft axle fuel tanks, these trucks use a fuel tank selector valve and solenoid assy.

The fuel tank selector switch is located on the right side of the heater control panel, switches the tanks and the gauge from one to another.

Why someone would install a toggle switch in place of the factory switch, I dunno. Could be they were unaware of the location of the switch or it was was defective.

The problem with these trucks is, the selector valves have been a POS since day one! There are several different types, which are years specific and some have 3 ports, some have 6.

 

Get rid of the toggle switch and go back to stock.
It will never work the way it's set up now.

 

Thanks to all who are interested. I think I understand how the system works now, and it seems to me that many folks out there have problems with this system.

So I ask: IS THERE A BETTER WAY?

Rather than go back to the same system that seems complicated and prone to failure, is there a more reliable, simpler way to achieve the result of working gas gauges and switchable tanks? I would not mind having to switch a valve or two manually.
If the existing system is the best option, which brand of parts are the best?

Can one easily put a mechanical pump on these 460's?

1984 f250 manual trans, 460, two tanks, pumps inside.

j66b

 

No.

OEM.

Kinda, but then you have to change the switch, the valve and all the wiring.

 

If you read through this very long thread in this link, you can learn a bit more about the fuel system and it's problems. This link is for the old diesels but they use the same valve as the 460's with dual tanks. Page 4 shows a picture of someone's brass manual valve system they rigged up.

Fuel Selector Valve Nightmare

Once you mount the manual brass valves(one for the supply system, one for the return system) you can go down on the frame rail and extend the wiring from the old valve up to a good spot and mount a toggle switch to switch the gauge wiring.

 

A lot of people (460 AND diesel) just use the six port Polak valve.

There are dozens of threads.
If its the valve and not the hacked wiring, its just a matter of splicing on the connector

 

I have two other old fords with mechanical fuel pumps: a '66 with a 352, and a '74 with a 300 six. Both have pumped fuel faithfully for decades without a whimper. I have a friend who has a big ford farm truck with a 460, and it has a mechanical fuel pump.

I looked at the timing cover on mine, and, right above the oil filter is a blocking plate on the drivers side of the cover. Mechanical fuel pumps for a 460 are readily available from Carter or Holley.

So, can anyone out there find a reason why I could not scrap the in tank electric pumps, relays, and tank valve and install two fuel lines, a T and a couple of valves, switch to the fuel gauge, and a mechanical pump?

Has anyone done this?
'84 F250, two fuel tanks, 460 carbureted.

I would be interested in any opinions.

Thanks, j66b

 

I have a mechanical fuel pump.
If you want to switch, I'd think you are going to have to change to the 6 port Pollak valve on the frame rail.

The 460 mechanical pump has a return port built into it.
You just need to make up a hard line to get from the pump up close to the carburetor.
I suggest adding an inline filter before the carb inlet.

 

What brand of mechanical pump do you have? What is the GPH rating? Could you explain the routing of the return line?

Thanks, j66b

 

I think it's a Carter M60443.
Replaced it in '08 when I installed a new engine.

The return line comes directly from the pump back to the switch valve on the frame rail.

 

I remember looking up a 460 equipped truck on Autozone or Advance's site, and they sold the mechanical pump with the return line on it for the 460's. They had it and the electric pumps also. Plug in your truck and see if you can find it. If it doesn't come up, try a different year with a 460.

The mechanical pump is not going to fix your problem though. It has nothing to do with the tanks switching.

 

Airtex sells the same pump with the same number.
You can get it pretty much anywhere for ~$30.

 

Dave F: What will solve the tank problem is the two manual 3 port ball valves that I am installing just to the left of the drivers seat.

My present setup sends the return line from what appears to be a pressure regulator just in front of the carb. It would be nice to simply hook the mechanical pump up to the same valve. Anyone have any thoughts on doing this?

Thanks, JB