Upgrades To Big Blue For Overlanding?

[Gary Lewis]

Bill - Does Darth have dual fuel tanks?  How do you have the fuel system set up?  What pumps, reservoirs, switching valves, etc?  The parts catalog shows a complex arrangement of reservoir, pump, filter, etc on the frame.  What do you have and what would you recommend?

[85lebaront2]

Gary, I used the 1990 fuel tanks and pumps. That is the year where Ford went to high pressure in-tank pumps. Since Big Ugly was a standard cab I had to extend the fuel lines 35" so I bought a Dorman fuel line repair kit which contained bulk line and fittings.

If you can find a 1985.5 to 1989 truck then you can get the 1985.5-1986 in-tank low pressure pumps and use the frame mounted reservoir and high pressure pump. If you use the early pump assemblies the senders will work with the stock gauges. Since I was originally planning on using the 1990 dash I wasn't worried about the change in fuel gauge senders.

[Gary Lewis]

I have the high-pressure pump from Huck, which is a '90, so could go that way.  But, apparently Huck was a single-tank truck as there's no switching arrangement in the lines.  And my catalog stops at 1989, so I don't know what parts were used on the later trucks.

But, I know that the 1985.5+ systems were problematic, so wanted to consider the later stuff.  What do you have to switch tanks?

[85lebaront2]

Biggest problem I see will be gauges, Ford changed the gauges somewhere between 1986 and 1989, the change will probably be where the ICVR goes away. The temperature gauge apparently works with either system and the oil pressure changed from being an actual gauge to an "oil pressure indicator" sort of a reverse idiot light but, by cutting the fixed resistor out of the circuit and using the old sender it becomes a proper gauge. The fuel gauges are the problem, older gauges read empty with an open circuit, later ones read beyond full with an open circuit. As far as I know the resistance of the senders changed when the gauges changed so that would be the issue.

As for the external high pressure pump, it was used from 1985.5-1989 after that it is the two high pressure in-tank pumps. The tank switching is just the dash switch and the pump modules have shuttle valves that do the change over. These also had issues, the shuttle valves would stick or leak and cause one tank to return into the other one.

[Gary Lewis]

I'm thinking the 1990+ system is the way to go because I think it would mesh best with the existing plumbing to the fuel rails.  But, maybe not since the 1985.5 - '89 system has an output and a return, so should connect right up to what I have.

So, forgetting the gauges, which system would you prefer?

As for the gauges, I don't think that will be a problem as I think I can put the earlier sender on the later pump, or vice versa.  I hope.

[85lebaront2]

I would use the 1990+ system, but there were some changes, in 1994 I believe. Best option is see if you can find a 1990-1992/3 truck, doesn't have to be a 460 for the lines and wiring that way you won't have to fabricate everything.

Can we say ADHD? Jumping from EFI on Dad's truck to EFI on Big Blue (I though Edelbrock carburetors were your Holy Grail, and I seem to recall being somewhat raked over the coals on my decision to go to EFI on Darth.

[Gary Lewis]

ADHD?  I prefer to say that I'm advancing in parallel on several fronts.  

Seriously though, if I'm learning EFI then why not do it on Big Blue as well as Dad's truck?  And, I'd rather use Big Blue as the guinea pig than Dad's, especially since it'll be the easier one to do as it will be close to a bolt-on.  And, what I learn on Big Blue will be directly applicable to Dad's truck.

For instance, there is the issue of the fuel system that needs to be sorted.  And, it is complicated for a couple of reasons.  First, the 400's & 460's didn't have EFI, so there are no bolt-on parts to buy.  Second, by the time the EFI'd 460's did come along in the Bricknose era the fuel gauge senders had changed to a reversed and different resistance range - totally incompatible with Bullnose gauges.

But, fortunately, Ford did offer the 302 w/EFI in '85 & 86, and they used the same high-pressure fuel pump as the 1987 and later 460's with EFI - as shown below.





That being the case, it would seem that the most straight-forward solution would be to use the 302's fuel system, which is:

In-tank pumps mounted on the correct 1980 - 86 sending unit so the fuel gauge works

Reservoir/Tank Selector Valve F1TZ 9B263-B (replaced E6TZ 9B263-C a/o 9/91)

Frame-mounted high-pressure pump E7TZ 9C407-B

So, what do y'all think?  Why won't this approach work for both a 400 and a 460?  (Parallel efforts.  )

[85lebaront2]

Yes, and that was the point I was trying to make earlier, the 1985.5-1986 pumps and tanks will be an easier solution for you due to the fuel gauge issue. Just be sure the HP pump you get is a Bosch, most of the aftermarket replacements are junk, noisy and failure prone. I stripped a neighbors wrecked 1986 F150 and kept the HP pump, Matt ended up putting it on his truck and it was still working when he sold it. On Big Blue, I suspect the front tank is already correct due to the pressure output.

[Gary Lewis]

Ok, I think we are on the same page.  But, let me throw in two wrinkles:

I have three brand new in-tank pumps from Vernon.  Why not use those instead of some EFI-specific ones, and put them on the new sending units I also have?

I also have a brand new 6-port selector valve from Vernon, the one those pumps are designed to switch.  Why not use it instead of the EFI-specific one?

[85lebaront2]

Gary, problem is the way the fuel system was plumbed for the 1985.5-1989 trucks. The in-tank pumps deliver fuel to the reservoir/tank selector assembly on the frame, this is where the high pressure pump picks up fuel from. Excess fuel from the tank selected is returned to that tank along with the return fuel from the engine. You can either use what Ford designed, or redesign it the way you want it. If I wanted to do away with the frame pump and reservoir, I would get a pair of Chrysler turbo or V6 pumps and install them on the 1985 pump/sender units, these are 75-80 or more psi capable pumps, then use your 6 port valve, provided it can handle the pressure, to switch tanks. The problem you will have, just as the present system does, will be starving the pumps, especially the front tank, on hard acceleration, braking and inclines when low on fuel.

Ford used the system on the early models so the high pressure pump would always have fuel, Chrysler uses a cute cup with the return acting as a jet pump to keep it full until the tank is pretty damn empty. Later Fords do the same with the pump module, it serves as a suction reservoir. FWIW, the high pressure pumps do not like being run dry.

[Gary Lewis]

Let me see if I understand - I shouldn't use the 6-port valve as there's no reservoir to keep the high-pressure pump supplied.  Right?

Said another way, just to check we are on the same page, the in-tank pumps that I have are fine, but I need a reservoir to supply fuel in all conditions to the high-pressure pump and the 6-port valve doesn't do that.

So, if I run the pumps I have and Reservoir/Tank Selector Valve F1TZ 9B263-B I should be good?  That way I'm using what Ford designed, although I'm not sure what in-tank pump they used as I can't find a part number on the pump by itself, just the pump/sending unit combo.  So, I'd like to use the sending units and pumps I have, which are right for a carb'd 460.

[85lebaront2]

Deadhead one or the other and check the pressure, I am not sure what the pressure for the LP in-tank pumps is and AllData doesn't give me that, just the main pressure.

[Gary Lewis]

That's the problem - I don't know what it should be, so wouldn't know if it is correct or not.  But, isn't the real question whether those pumps will trigger the valve to switch?

They supply enough fuel to run the engine, even at full chat.  And the high-pressure pump will circulate fuel to the regulator and back to the reservoir, so if the pumps provide enough pressure to switch the valve wouldn't that be all that is needed?

I'll continue to look for the right in-tank pumps for an EFI setup, but so far all I've found is the whole sending unit/pump combo.  And since I have both new sending units and new pumps for the carb'd version I'd like to minimize cost and use them if they'll work.

[85lebaront2]

One thing you may run into, I seem to remember seeing a 1989 that had the fuel lines coming in to the rail near the front of the engine due to the location of the pump and filter on the frame rail.

[Gary Lewis]

You are saying that the lineup of "stuff" on the frame may bring the filter so far to the front that the lines can't go up the back of the tranny like on Huck, as shown below.  Right?

If so, perhaps I can start the lineup further to the rear, meaning run the lines from the front tank rearward rather than forward.  I'll have to look to see what's on the inside of Big Blue's frame now, but not much other than wiring that I remember.

And, so far no luck on the pump part number for the in-tank pumps.  Ford didn't sell them other than as part of the whole sending unit assembly, so no part number to cross-reference.  LMC doesn't tell, but I'm checking other sources.  Perhaps Delphi?

[85lebaront2]

Ok, did some digging around, best I could find is the in-tank pumps are probably 9-10 psi which would probably be what you have currently since you have to drop it down for the carburetor. Location of the equipment from what I remember should be about where I circled on your picture. If you move it back about where the transmission cross member sits everything might fit and work. On the factory setup on Darth the 6 port tank selector valve was between the front end of the front tank and the frame.


Picture showing approximate location of 6 port motorized valve.

[Gary Lewis]

Bill - Thanks.  That location should work fine since I should be able to route the lines you see to the front instead of the rear.

However, I think I may have an answer to my pump question: Here's the summarized info from Delphi's catalog:

High-pressure pump for 1986 5.0L w/EFI: FD0029, which flows 28 gph, works at 44 psi, and has a relief at 90 psi

1986 5.0L EFI in-tank pump: FE0484, which flows 30 gph, works at 2 psi, and has a 6 psi relief

1985 460 carb in-tank pump: FE0127, which flows 24 gph, works at 36 psi, and has a 65 psi relief

I have two brand new FE0127's, and that would seem to be a no-go.  However, here's the 1987 F250 460 page from Dephi, and it shows the FE0127 used for the aft-axle plastic tank and the FE0484 used for the aft-axle steel tank.  HELP!

[85lebaront2]

You are running into what I did on Darth originally, metal or plastic tanks, damn nightmare. Let me do some digging later. I believe the FE0127 may be either wrong or the wrong specs.

[PetesPonies]

Gary, you listed pumps pressures are spot on for the first two. Most any SEFI system operates about 40-45 PSI. TB systems operate much lower. But what I don't understand is the pressure for the carburetor system. Anything over, about,  5-7psi will lift the needle. I know it can be regulated down, but I can't understand why that lists such a high pressure for a carb. The typical low pressure in tank pump works pretty good for a carbureted engine.

[85lebaront2]

Ok, found some information, using 1989 as a MY I found:
Precise 402P2485 pump only, rear steel tank low pressure says 6 psi
Precise 402P2487 pump only, for 17 or 19 gal center tank says 7 psi
Delphi FE0484 pump only, for steel rear tank says 2 psi
Delphi FE0070 pump only, for 17 or 19 gal center tank says 36 psi

Good luck with it, I would say if your in-tank pumps produce around 6-12 psi they should operate the switching valve without a problem.

FWIW, the carbureted in-tank pumps are essentially centrifugal pumps, the EFI LP pumps I believe are gearotor style pumps (miniature oil pumps).