EFI For Big Blue

[Gary Lewis]

Here are the pictures I took earlier of the 1995 front fuel lines from Jim:

I think blue is supply and gray is return.

Closeup of gray spring lock connector.

Closeup of blue spring lock connector.

Closeup of gray push lock connector.

Closeup of blue push lock connector.

And one more picture suitably labeled.

Bill - You've got a tank just like mine! Wait! It IS mine!

I wondered if that was the recall valve. There's one on both of the FDM's.

And, thanks for the pics. That helps me understand what the other connectors look like. And, by the way, I think both burned connectors are/were straight. But I may have to buy the kit since I'm doing two trucks - eventually.

I spent quite a while today drawing up the 1996 fuel system wiring as well as the 1985 fuel system wiring. I'm not ready to post that work yet, but I can tell you that it is amazing how simple the 1996 system is and how complex the 1985 system is. I'm just gobsmacked at the difference. WOW!

I want to be able to see what I'm going to do, what I'm taking out, and how I'm going to interconnect things. That's why I'm drawing the two systems up, and hope that work will be useful on both Big Blue and Dad's truck, as well as others that follow in my footsteps.

[85lebaront2]

Bill - You've got a tank just like mine! Wait! It IS mine!

I wondered if that was the recall valve. There's one on both of the FDM's.

And, thanks for the pics. That helps me understand what the other connectors look like. And, by the way, I think both burned connectors are/were straight. But I may have to buy the kit since I'm doing two trucks - eventually.

I spent quite a while today drawing up the 1996 fuel system wiring as well as the 1985 fuel system wiring. I'm not ready to post that work yet, but I can tell you that it is amazing how simple the 1996 system is and how complex the 1985 system is. I'm just gobsmacked at the difference. WOW!

I want to be able to see what I'm going to do, what I'm taking out, and how I'm going to interconnect things. That's why I'm drawing the two systems up, and hope that work will be useful on both Big Blue and Dad's truck, as well as others that follow in my footsteps.

Gary, the 1990 up system really does away with the over engineered 1985.5-1989 system. If you were to use the early low pressure in-tank pumps, even with a selector valve (would need to be 6 port), you would still need some sort of reservoir for the high pressure pump so it wouldn't starve on braking, steep grades etc. You could probably use some sort of moderate pressure container like an old GM VIR tank and have a tee for the return, supply into it and a dip tube to near the bottom for the high pressure (Bosch is what Ford used) pump. The 6 port valve would solve the selection portion and it would work just like the early Ford EFI systems did. It would only need to handle about 10 psi to be safe.

The 1990 up just has two tees in the lines, one for supply and one for return, everything else is done in the pump modules.

[Gary Lewis]

Gary, the 1990 up system really does away with the over engineered 1985.5-1989 system. If you were to use the early low pressure in-tank pumps, even with a selector valve (would need to be 6 port), you would still need some sort of reservoir for the high pressure pump so it wouldn't starve on braking, steep grades etc. You could probably use some sort of moderate pressure container like an old GM VIR tank and have a tee for the return, supply into it and a dip tube to near the bottom for the high pressure (Bosch is what Ford used) pump. The 6 port valve would solve the selection portion and it would work just like the early Ford EFI systems did. It would only need to handle about 10 psi to be safe.

The 1990 up just has two tees in the lines, one for supply and one for return, everything else is done in the pump modules.

That is excellent documentation. Thanks! I'll have to look at my EEC-IV book to see if it has any further info on this subject.

As for the 85.5-89 system, I'm not sure it is "over engineered". It looks cobbled together to me. Here's a run-down of the parts:

• 1985.5-89: Has a fuel pump cutoff relay, a tank selector relay, oil pressure switch, inertia switch,

  fuel tank selector switch, fuel tank selector valve, a resistance wire, and two in-tank pump/sender units.

• 1990+: Has a fuel pump relay, PCM, inertia switch, fuel tank selector switch, and two in-tank pump/sender units.

But the wiring diagram makes the difference look even more dramatic. I can't wait to get that finished and share it.

By the way, the 1985.5+ system uses a relay to power the pumps, while the 1990+ system uses the tank selector switch w/o a relay. See any problems?

[85lebaront2]

That is excellent documentation. Thanks! I'll have to look at my EEC-IV book to see if it has any further info on this subject.

As for the 85.5-89 system, I'm not sure it is "over engineered". It looks cobbled together to me. Here's a run-down of the parts:

• 1985.5-89: Has a fuel pump cutoff relay, a tank selector relay, oil pressure switch, inertia switch,

  fuel tank selector switch, fuel tank selector valve, a resistance wire, and two in-tank pump/sender units.

• 1990+: Has a fuel pump relay, PCM, inertia switch, fuel tank selector switch, and two in-tank pump/sender units.

But the wiring diagram makes the difference look even more dramatic. I can't wait to get that finished and share it.

By the way, the 1985.5+ system uses a relay to power the pumps, while the 1990+ system uses the tank selector switch w/o a relay. See any problems?

The FPR is behind the left side equipment from 1987-1991, from 1992-97 it is in the PDC, look at the 1996 EVTM. In the page you posted it is on the left side and is labeled "Fuel Pump Relay".

[Gary Lewis]

The FPR is behind the left side equipment from 1987-1991, from 1992-97 it is in the PDC, look at the 1996 EVTM. In the page you posted it is on the left side and is labeled "Fuel Pump Relay".

Ok, my bad. I said it poorly. The 1985.5-89 setup has the tank selector switch controlling a relay, which then powers the pump. But the 1996 system has a fuel pressure relay in the PDC, and that feeds the tank selector switch - which then powers the pump directly. IOW, no relay between the tank selector switch and the pump in '96.

Just wondering if the Bullnose tank selector switch is up to that.

[NotEnoughTrucks]

Ok, my bad. I said it poorly. The 1985.5-89 setup has the tank selector switch controlling a relay, which then powers the pump. But the 1996 system has a fuel pressure relay in the PDC, and that feeds the tank selector switch - which then powers the pump directly. IOW, no relay between the tank selector switch and the pump in '96.

Just wondering if the Bullnose tank selector switch is up to that.

Gary, I think you are mixing some of the 460 fuel handling components with the EFI setup.

The tank selector handles the power directly to the in tank pumps. No relay. The EFI fuel pump relay provides power to the inertia switch, which is then distributed to the frame mounted pump and the tank switch common. The contact side of the tank switch selects either the front or rear in tank pump.

No oil pressure switch, no post tank switch relays.

[Gary Lewis]

Gary, I think you are mixing some of the 460 fuel handling components with the EFI setup.

The tank selector handles the power directly to the in tank pumps. No relay. The EFI fuel pump relay provides power to the inertia switch, which is then distributed to the frame mounted pump and the tank switch common. The contact side of the tank switch selects either the front or rear in tank pump.

No oil pressure switch, no post tank switch relays.

Ray - Let me get the schematic done and posted and then I think we will find we are in complete agreement. Right now the drawings are done for both versions, but the 85.5-6 is so poorly laid out that you can't make heads or tails of it. But I will work on it as soon as I finish this second cup of Joe.

[Gary Lewis]

Ray - Let me get the schematic done and posted and then I think we will find we are in complete agreement. Right now the drawings are done for both versions, but the 85.5-6 is so poorly laid out that you can't make heads or tails of it. But I will work on it as soon as I finish this second cup of Joe.

Ok, as promised, here are my versions of the 1985.5-86 and 1996, and probably later, fuel system wiring diagrams. They don't, yet, have the wire colors and other information, but I hope you can see the complexity of the 1985.5-86 system and the simplicity of the 1996 system. (EDIT: They now have the wire colors and pinouts.)

And, by the way, I put them up on a hidden test page on the website to see how easy they would be to read there. Please take a look at let me know how easy they are to read for you there.

And, if you spot any errors or areas for improvement, PLEASE let me know. These need to be spot-on accurate so I (we?) can use them for wiring.

Also, from this you can see what I was saying about the tank selector switch powering the pumps directly in the 1996 version, but doing so via a relay in the 1985.5-86 version.

[Gary Lewis]

Ok, as promised, here are my versions of the 1985.5-86 and 1996, and probably later, fuel system wiring diagrams. They don't, yet, have the wire colors and other information, but I hope you can see the complexity of the 1985.5-86 system and the simplicity of the 1996 system. (EDIT: They now have the wire colors and pinouts.)

And, by the way, I put them up on a hidden test page on the website to see how easy they would be to read there. Please take a look at let me know how easy they are to read for you there.

And, if you spot any errors or areas for improvement, PLEASE let me know. These need to be spot-on accurate so I (we?) can use them for wiring.

Also, from this you can see what I was saying about the tank selector switch powering the pumps directly in the 1996 version, but doing so via a relay in the 1985.5-86 version.

And, for your viewing pleasure (really so I could find them) I added a page to the website to house these diagrams: Fuel Systems/Fuel System Wiring. I included the relevant EVTM pages as well as a way to "download" my schematics - but it really just opens them in a new window in your browser. However, in my case it brings it up close and personal, so is much easier to see.

Now to figure out what needs to change in the wiring to incorporate the '96 stuff into Big Blue.......

[85lebaront2]

And, for your viewing pleasure (really so I could find them) I added a page to the website to house these diagrams: Fuel Systems/Fuel System Wiring. I included the relevant EVTM pages as well as a way to "download" my schematics - but it really just opens them in a new window in your browser. However, in my case it brings it up close and personal, so is much easier to see.

Now to figure out what needs to change in the wiring to incorporate the '96 stuff into Big Blue.......

You might also want to add the 1986 stuff as it has a slightly different system and add the EFI pump system also so those with the 1985.5-1986 5.0L engines can find their information. Nicely done though sir!