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1986 F350 - 460 7.5L - in-tank or in-line fuel pump

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ramses

1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Bought truck with an in-line fuel pump and manual switch (done by previous owner), but fuel gauge was disconnected. Old sending unit is still in tank (side mount tank) as well as 4-pin connector, just not connected. Thinking of getting new sending unit to both have fuel gauge working and a pump that I dont have to turn on and off. However, saw some models have an additional in-line pump. My engine does nto have fuel injection, so do I need to keep the in-line pump? Or take it out and just use sending unit?

If I need to keep it is there any wiring I have to be aware of?

Gary Lewis

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

This sounds so similar to another that's currently being worked. You might want to read through this thread: http://forum.garysgaragemahal.com/Misfire-wont-smog-test-Need-some-advice-td56255.html as it might have some info for you.

Having said that, if you have a manual switch to turn the pump on then you have a ticking time bomb. If you get into an accident the pump will keep on pumping.

So, if it was my truck I'd put it back essentially stock. In fact, I did just that. Big Blue was badly butchered in this area and I had to reconstruct it, so I'm familiar with this area and issue.

The wiring diagrams are here: Documentation/Electrical/EVTM/1986 EVTM and then Electric Fuel Pump Control. The diagram for a single tank is shown below. The key is the oil pressure switch and the inertia switch. Those need to be controlling the pump.

But that doesn't mean you have to ditch your pump. You could keep it, but just control it with those two safety items.

Having said that, do you know if you have an electric pump in the tank? If so, is it good?

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

ramses

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Dont know if there is a pump inside the tank (although it has a sending unit installed) or if its working. Will try to test. Should I take it out first and inspect tank? Its empty right now.

If I keep the in-line, what are the benefits?

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From: Gary Lewis [via Bullnose Enthusiasts] <ml+[hidden email]>
Sent: Thursday, April 16, 2020 7:06:41 PM
To: ramses <[hidden email]>
Subject: Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

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 in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

If you reply to this email, your message will be added to the discussion below:

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Gary Lewis

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

Taking the sender out is a pain, but if the tank is truly EMPTY it isn't too hard. But if it has some in it the sloshing can make it unwieldy. However, there's not a lot to see if you take it out, so how will you know if it works?

The previous owner probably put the extra pump on for a reason - like the one in the tank is probably bad. So if you want to keep it, then maybe all you need to do is to put the safeties back in place and run the pump with them. And you may be able to pull the wiring for the pump out of the 4-pin connector so the sender still works.

Does the truck run ok on the new pump?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

In reply to this post by ramses

A cab & chassis will only have the side tank.

If you can peek at the top, (with a cell phone or whatever) look at the plug in the bung.
4 wires means it came with an in-tank pump, two wires, and it had a mechanical pump on the side of the timing case.

Setting it back to stock (so it is safe) should not be a problem.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ramses

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Yes, truck runs ok with new pump, but its awkward to manually turn on and off. Hadnt thought of safety issue, so now its even more important.

The harness has 4 wires, so it should have in-tank pump. Makes sense the inline was installed to "replace" faulty in-tank pump but since schematic shows both, could it be it ised both?

Should I keep both working in series? Looks as if both are tied in to the right source wire they could work safely. But, again, should I use both or choose one?

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From: ArdWrknTrk [via Bullnose Enthusiasts] <ml+[hidden email]>
Sent: Thursday, April 16, 2020 7:54:29 PM
To: ramses <[hidden email]>
Subject: Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.

If you reply to this email, your message will be added to the discussion below:

http://forum.garysgaragemahal.com/1986-F350-460-7-5L-in-tank-or-in-line-fuel-pump-tp57046p57065.html

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kramttocs

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

In reply to this post by ArdWrknTrk

Just to note - I had an 86 with the plastic rear tank (along with our 94 and 95). Not sure if it started in 86 (like the 4wd) or not. This truck also had the really heavy LS rear end so it was a little unique. My 80, 85, and other 86 are just the side tanks.

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

Gary Lewis

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

In reply to this post by ramses

I don't think you want to run both. If the truck runs on the add-on pump I'd use it and get the wiring to it set up so the inertia switch and oil pressure switch are being used correctly.

Gary, AKA "Gary fellow": Profile

ramses

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

UPDATE 1:

Went under the hood today. Tracked down fuel pump power (pink/black) and it goes to a connector which splits into two (2) pink/black wires, one thicker than the other (Picture 1). This one goes left to what I'm guessing is a relay (I have very little experience on this) near the hood hinge (Picture 2). In fact dont know what any of the three parts in Picture 2 are.

The thinner pink/black, and a yellow wire, loop along the front to the passenger side and into the cabin, where I found this hanging (Picture 3). Inertia switch? Something rattles inside. It was close to where the arrow points.

Here is where it gets messy. Behind the battery the pink/black and yellow reach a connector where the pink/black ties into a blue wire with a fusible link, but the blue wire is cut (Picture 4). So I know the switch in the cabin is disconnected.

But the one that concerns me even more is back on the driver's side. The pink/black wire, that should loop to the passenger side, has a jumper (red wire I'm holding in Picture 5) going into a red wire in another branch. Don't know where that other red goes or what it does, so again any input is appreciated.

So I dont know if the oil pressure and inertia switches are in the loop or not. Quite sure In need to take the red jumper out and reconnect the blue wire, but is there any troubleshooting/testing in between?

In the mean time, took bench seat out, pulled old vinyl, gave frame wire wheel and rust converter. Got sliders loose and oiled but missing a spring and wire that connects both sliders' mechanisms. But guess I'll leave that for another thread.

ramses

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Oh, and along with the wiring in this area (drivers side), I found these loose contacts. Only thing close that seemed to match was this connector but, again, no idea (Picture 6). Just a random find.

Gary Lewis

Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

In reply to this post by ramses

You've found part(s) of the problem. Your blue wire is Fuse Link S in the schematic below, and that may not reconnect very nicely, but you will need it. From there the yellow wire goes to the inertia switch, which is bad. From that the yellow wire runs to the relay you pointed out, which is the fuel pump relay.

From there the pink/black wire goes to C120. The pink/black coming in from the top is from the ignition switch which gives the pump full battery voltage in Start. Otherwise it gets reduced voltage due to the .75 ohm resistor.

So you need to figure out why the blue fuse link was cut and replace the inertia switch. And more? The red wire? I got lost there.

Gary, AKA "Gary fellow": Profile

ramses

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Well that’s a start. Thanks Gary. Having trouble finding inertia switch online. Is there a part number

Also, where is the oil pressure switch located?

Ramses

Sent from Mail for Windows 10

From: [hidden email]
Sent: Friday, April 17, 2020 8:13 PM
To: [hidden email]
Subject: Re: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

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 in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

If you reply to this email, your message will be added to the discussion below:

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ArdWrknTrk

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

The oil pressure switch is at the center back of the engine block, behind the intake manifold.

It should be attached below the oil pressure sender, which is a little tin can looking thing with a wire on top.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

In reply to this post by ramses

Test the inertia switch first.
It may be fine.

Connect a multimeter to each side, hold it upright and press the reset button.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

I've added the inertia switch to a tab called Part Numbers here: Documentation/Fuel Systems/460 Fuel Systems. But for simplicity and ease of use:

Gary, AKA "Gary fellow": Profile

ramses

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Thanks guys. Now, how do I know if the fusible link in the blue wire is good. Just test continuity?

Sent from Mail for Windows 10

From: [hidden email]
Sent: Saturday, April 18, 2020 8:32 AM
To: [hidden email]
Subject: RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

I've added the inertia switch to a tab called Part Numbers here: Documentation/Fuel Systems/460 Fuel Systems. But for simplicity and ease of use:

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 in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

If you reply to this email, your message will be added to the discussion below:

http://forum.garysgaragemahal.com/1986-F350-460-7-5L-in-tank-or-in-line-fuel-pump-tp57046p57222.html

To unsubscribe from 1986 F350 - 460 7.5L - in-tank or in-line fuel pump, click here.
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Gary Lewis

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

Two things. First, to test the fuse link you'll have to see if there is voltage on the side pointing toward the starter relay on the fender. Then you'll have to see if the other side connects to the inertia switch w/o going to ground. If so, then you could solder the two ends of the fuse link back together.

Second, while it is your thread and you can do whatever you want, if when replying by email you'd click the three dots shown below and delete all the extraneous baggage, meaning the previous comments that are in the response, your thread would be a lot easier to read.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

Administrator

I wouldn't solder the fuselink back together.

Just install a new one.
Cheap enough, and you know it's right.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ramses

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

In reply to this post by ArdWrknTrk

Hi Jim. Are the oil pressure switch and sender parts that should be replaced? Meaning, are they prone to wear. Just want to make sure to dot all i's and cross all t's.

ramses

RE: 1986 F350 - 460 7.5L - in-tank or in-line fuel pump

In reply to this post by Gary Lewis

Hey Gary. Sorry for that. Hadn't noticed that would happen replying by email. I'll try testing that tomorrow.

Mean while, would you know which connector this is?

Just odd to find these two bare contacts bit they seem to fit and its the only open plug in the area. This second picture shows were the contacts lead from.