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Black Beauty has fuel pump electrical issues

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Greg 85

Black Beauty has fuel pump electrical issues

Hello, my name is Greg and I am in Virginia, I have a 1985 Ford F150 Explorer with a 5.0L EFI/AOD 2WD longbed. All original except for paint color and stereo. This is my first of two Ford trucks. I bought this truck as a non running project because the body and interior were immaculate for its age. They previous owner had done a lot of work on the body and interior but the engine and drivetrain left a lot to be desired. I towed the truck home and started work on the engine, turned over and had spark but no fuel. Traced it back to the relay. Replaced relay and connector, started, ran like crap but ran. Ended up changing the idle air solenoid and fuel pressure regulator. Ran good but wouldn't shift correctly, adjusted the TV cable and tore down the tailshaft and cleaned reassembled the governor and still wouldn't shift right. Changed the air filter and now shifts fine (go figure). Drove the truck around for two months and then started acting like it was starving for fuel. Ended up acting like HP fuel pump wasn't putting out, Replaced along with new fuel filter. No change, so I dropped both tanks and replaced with new including senders and pumps/strainers. Startes and runs but dies after about 20 mins of running. Still have spark, no fuel. Come to find out it had a intermmitten short, when I would check for power it was there but would cut out while running. Bought a Chiltons magazine, no diagram for 85 fuel injected, traced wires best I could, replaced inertia switch just in case, no change. Replaced every ground wire, strap and cable, no change. Pulled every connector and cleaned corrosion off, no change. I bypassed the factory harness with a makeshift power source and switch to the HP fuel pump(Temporary for testing), runs like a champ, drives like it should. Any advice would be helpful!

Greg Gorbet:
1985 Ford F150 Explorer, 5.0 EFI, AOD, Longbed, black and blue, 2WD, all stock project.
1983 Cheverolet C10, 427 SBC, TH400/reverse, back halfed w/Ford 9" on 4-link, Project.
1979 C10, 383 SBC, TH350, Big 10 on leafs w/ladderbars, Saturday night special/date truck.
1985 Sport-Craft 272 Fishing Boat

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

Greg - Good job on the signature.

On the high pressure pump problem, the system isn't too complicated, as shown below from the '85 EVTM. (I've assumed that yours is a single tank system.) Where did you jump from and to with your makeshift power?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Greg 85

Re: Black Beauty has fuel pump electrical issues

It is actually a dual tank set up and I had completely bypassed the factory wiring and hooked up directly to the battery with a toggle switch for testing purposes.

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

That's a bit more complex, but not too bad.

I'd start through the system inch by inch, starting at the tank selector valve/switch. If that doesn't work you won't get voltage to the pump. And they are a known problem.

Gary, AKA "Gary fellow": Profile

Greg 85

Re: Black Beauty has fuel pump electrical issues

Gary Lewis wrote

That's a bit more complex, but not too bad.

I'd start through the system inch by inch, starting at the tank selector valve/switch. If that doesn't work you won't get voltage to the pump. And they are a known problem.

Thank you! It is raining now but when it dries up, I will take a gander at it and see if I can locate the issue. I will let you know what I find. And again Thank You!

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

Welcome. That switch/valve is on the frame roughly below the driver, IIRC. As said, it is a known problem and is sometimes hard to find and expensive if you do.

Gary, AKA "Gary fellow": Profile

1986F150Six

Re: Black Beauty has fuel pump electrical issues

Administrator

Gary Lewis wrote

That switch/valve is on the frame roughly below the driver, IIRC. As said, it is a known problem and is sometimes hard to find and expensive if you do.

E3TZ-9189-A?

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

No. That's the valve by itself from what I remember. He needs the switch/valve combo. I think this is it, from our page on Documentation/Fuel Systems/Fuel Systems Part #'s/Fuel Tank Selector Valve:

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: Black Beauty has fuel pump electrical issues

Administrator

Two items, (a) I would use the 1986 diagram. I have never seen a 1985 wired like the EVTM shows. (b) in the reservoir/tank selector valve on 1985/86 only is a filter element that looks like one in some of the old mechanical pumps. If it is clogged you will have fuel starvation problems.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

Good point, Bill. I've included the '86 schematic below. It'll be interesting to see how his is wired.

As for the filter, I'm not sure that is it as he ran a jumper to the pump and that solved the problem. But, do you think that by bypassing the resistor in the wiring that could do it with a dirty filter?

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: Black Beauty has fuel pump electrical issues

Administrator

The difference is in the tank selector valve, all 1985/86 EFI trucks I have seen had the big reservoir tank selector valve. The only resistors were on the in-tank pump carbureted trucks (460 w/hot fuel handling package). If he hot wired both sides of the system (power and ground) and it works, I would look at G701 as the entire system grounds there.

Bill AKA "LOBO" Profile

Greg 85

Re: Black Beauty has fuel pump electrical issues

In reply to this post by Gary Lewis

I believe mine is the latter due to the fuel pump cutout relay. Hopefully it will dry out enough today for me to crawl under it and start searching for the issue.

Greg 85

Re: Black Beauty has fuel pump electrical issues

In reply to this post by 85lebaront2

85lebaront2 wrote

The difference is in the tank selector valve, all 1985/86 EFI trucks I have seen had the big reservoir tank selector valve. The only resistors were on the in-tank pump carbureted trucks (460 w/hot fuel handling package). If he hot wired both sides of the system (power and ground) and it works, I would look at G701 as the entire system grounds there.

I am trying to figure out the^^^^ "big reservoir tank selector valve" as I have a fuel filter housing with the big tank and filter, but if memory serves I believe my selector valve is seperate? Am I following that correctly?

Greg 85

Re: Black Beauty has fuel pump electrical issues

In reply to this post by Greg 85

Greg 85 wrote

It is actually a dual tank set up and I had completely bypassed the factory wiring and hooked up directly to the battery with a toggle switch for testing purposes.

Allow me to clearify this, I only bypassed the high pressure pump, the rest of the system was connected to the factory harness and was working as it should. I had fuel to the HP pump but the HP pump wasn't engaging to build the pressure. So I disconnected the HP pump power and ground and connected power and ground by the battery through a toggle and had no issues. Ran good. So I will need to trace out the wiring for the HP pump and find the power loss. Right?

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

Yes, you need to follow the wiring and find out where the power stops. And to clarify, if you have the wiring shown in the '86 EVTM then there is no resistor. So disregard what I said about that.

Further, that diagram doesn't show the switch built into the unit on the frame. Just the switch on the dash. So it is less complex and should be easier to resolve.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: Black Beauty has fuel pump electrical issues

Administrator

In reply to this post by Greg 85

Greg, if the filter/tank unit has 6 ports (3 large and 3 smaller ones) they should be plumbed with one large port to the HP pump, and the adjacent smaller port to the fuel return on the engine fuel rail. The primary filter should be in front of the HP pump. The top portion of that assembly is a diaphragm operated tank selector valve. Whichever in-tank pump is active moves the in-feed to the reservoir to that port and opens the corresponding return line to that tank.

The other 4 ports will be: 1 large and one smaller to the front tank and 1 large and one smaller to the rear tank.

If the in-tank pumps are working then the power/ground factory wiring is good to that point. Your issue would probably be in connector C127 at the pink with black dash? wire. The fuel tank selector is on the "upstream" side of that so power is good to there, the ground side should also be good due to the way the system is wired. Any breaks in the portion of the harness to the HP pump on either side, power or ground will prevent it from running.

Bill AKA "LOBO" Profile

Greg 85

Re: Black Beauty has fuel pump electrical issues

85lebaront2 wrote

Greg, if the filter/tank unit has 6 ports (3 large and 3 smaller ones) they should be plumbed with one large port to the HP pump, and the adjacent smaller port to the fuel return on the engine fuel rail. The primary filter should be in front of the HP pump. The top portion of that assembly is a diaphragm operated tank selector valve. Whichever in-tank pump is active moves the in-feed to the reservoir to that port and opens the corresponding return line to that tank.

The other 4 ports will be: 1 large and one smaller to the front tank and 1 large and one smaller to the rear tank.

If the in-tank pumps are working then the power/ground factory wiring is good to that point. Your issue would probably be in connector C127 at the pink with black dash? wire. The fuel tank selector is on the "upstream" side of that so power is good to there, the ground side should also be good due to the way the system is wired. Any breaks in the portion of the harness to the HP pump on either side, power or ground will prevent it from running.

I hooked everything back up as it should be, tried to start, started ran decent for thirty minutes, surging up and down but running. Test drove to gas station. Turned off, fueled, started back up with no issue other than the surging. Let run a few minutes and then put it in gear and it died, wouldn't restart. Popped the hood, wiggled wires, crawled underneath wiggled wires, tried to start c.n.s. waited about 15 minutes and tried again, acted like it wanted to. Tried again, started still surging, drove home. Once home popped the hood while running and wiggled wires up top and bottom no issues, sat down by the truck with a glass of sweet tea going through the schematic and it just died out of nowhere. Continuing to trace wires unless you think that I am barking up the wrong tree. Thoughts?

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

Have you checked the fuel pressure? I think that's where I'd start. That's because an electrical issue should be binary - on or off. But you have fluctuating symptoms. So I'd look elsewhere.

And, what about pulling codes?

Gary, AKA "Gary fellow": Profile

Greg 85

Re: Black Beauty has fuel pump electrical issues

Gary Lewis wrote

Have you checked the fuel pressure? I think that's where I'd start. That's because an electrical issue should be binary - on or off. But you have fluctuating symptoms. So I'd look elsewhere.

And, what about pulling codes?

Okay, so I would check fuel pressure but I cannot find a schraider valve/ port to connect to. I have looked up and down the rail, in the front and back and cannot find one. Is it hidden?

Also, I have a scanner but it is for obd2, isn't an '85 a obd1? Should I purchase a scanner for obd1? I have not seen a CEL on but that doesn't mean the bulb aint blown and its full of codes.

Do you think it is possible that I have a ignition module or coil breaking down when it gets to running temp? This was my next move prior to your response.

Gary Lewis

Re: Black Beauty has fuel pump electrical issues

Administrator

Some of the early EFI rails didn't have a schrader valve, so that may be what you have.

To pull codes you don't need a reader. Go to Documentation/Electrical/Electronic Engine Controls (EEC) and then the tab for EEC-IV and the Checking Codes tab.

But, you could be right about a component breaking down. However, anything that would do that would likely be in the ignition system. Have you checked for spark when it runs poorly or doesn't run?

Gary, AKA "Gary fellow": Profile

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