1986 F250 Can't find a rear tank sending unit

[mat in tn]

try bronco graveyard also and possibly NPD

[Tony69]

unfortunately non of them have it  I was thinking maybe a different style one would fit but as mentioned earlier I kinda can't afford buying multiple units and then sending them back.

I have one in the f150 but its a single line and two prong connector style. I wonder if I could somehow scavenge and modify it, running external pump to make it work. These tanks are such pain in the ass but its nice to have two...

[kramttocs]

Prepare your wallet

https://www.ebay.com/itm/296350194998?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=qxlfydLMS1a&sssrc=4429486&ssuid=YiQv5p8oTKK&var=&widget_ver=artemis&media=COPY

[Gary Lewis]

Yikes!  Glad I changed over to 96 tanks and units.

[Ifitaintbroke]

Alright folks, time for me to chip in. I spent a lot of time back in '20 looking for this exact same unit. I've come to the conclusion that they do not exist in the aftermarket and possibly never existed as a replacementpart from Ford. Here's why: in my catalog at work (this problem is actually how I landed my job at a parts store) the ONLY rear sending unit listed is for a plastic tank. Mine, as the OP's, is steel. 87 had a steel tank. The same tank. I could not find a 86 rear unit for a steel tank anywhere, so I tried one for an 87 as it is essentially the same tank. Here's the problem: in 87 Ford changed the ohm range in the gauge, and therefore the sender. My gauge would read backwards, as Jim's does with his 87 gauge and pre-87 sending units. Apparently, as Ford is apt to do, they used some 87 tanks in 86 trucks, and made a "custom" sending unit for them using essentially an 87 sender with an 86 reostat. This piece is a true unicorn. That's my theory anyway. To put it short: if you are looking for this unit, you are wasting your time.

As for the unit listed on Ebay above, it very well could be the same one, making me wrong. It certainly looks like my old sender. My concern is, what is the ohm range? It's probably the 87 and up range.

Could be wrong though!

[kramttocs]

Hmm interesting idea. I will say it took awhile for one to pop up (I bought it not too long ago for a fraction of this current price) and was surprised to see another one show up so soon.
So based on that I would definitely put them in the 'few and far between' category.

If you want and can tell me what test you want me to do, happy to grab my multimeter and check the nos one I have.

[Ifitaintbroke]

All you do is hook up a multimeter set to ohms on the 2 terminals going to the sender. Should be easy to identify. Then, check resistance at the extreme ends of float travel. Should be ~73 ohms with float all the way down, and ~10 ohms with the float all the way up.

[kramttocs]

9.2 to 69.

Matches the pre-87:

https://faq.speedhut.com/kb/fuel-level-gauge-faqs/what-are-some-typical-oem-fuel-level-sender-ohm-resistance-o-ranges

So looks like just a not very common replacement part. While the price of the current ebay listing is a bit crazy, for someone wanting a drop in replacement, it's an option at least.

[Ifitaintbroke]

Wow. I'm surprised. That is a direct replacement. If I'd found that 4 years ago, I'd have snatched it up, price be cursed.

[T_Auto]

We recently fought this same problem at our automotive repair shop. After looking over the wiring schematics and seeing that the 7.5 and 5.0 fuel system was wired almost identical led me to look up what a rear fuel pump for an 86 Ford F250 with a 5.0 looked like. And it was the one we needed! The Carquest part number was HS3496087.

[mat in tn]

it may look like what you need but are you sure that it supplies the correct pressure? it may but try to be certain. the 86 5.0 used two/three pumps in series. a low pressure in the tank /tanks with a high pressure boost pump on the frame rail to achieve efi pressures. is the f250 still carbureted? if so, it may be the same pump

[ArdWrknTrk]

You're right Matt, but low pressure for EFI is still more than a 4180 can handle.

The poster may have to do like Gary and replace the vapor separator up on top of the intake behind the coil with a return regulator set to 5psi.

I'm sorry, but the exact Holley number that Gary used escapes me ATM.  

It's certainly posted in multiple threads....

[85lebaront2]

I went through this when I first bought Darth, the front tank had a rusted through seam area and the rear tank pump was dead. Pep Boys had the only listing for the 460 W/hot fuel handling package. They are a centrifugal pump that delivers 5-7 psi according to what I have on AllData.

[mat in tn]

true that adding a regulator can be a good safeguard. I have done both over the years.

[ArdWrknTrk]

The 5.0 pump is too high a pressure and not nearly a gallon a minute, like the 460 spec.

[viven44]

I bet that 5.0 setup with 2 fuel pumps to boot would be right up Bradley's alley

In that 2 fuel pump setup, if one of the pumps dies, its game over. If the low pressure pump dies, the high pressure pump will vapor lock the fuel on the suction side immediately. If the high pressure pump dies, obviously that is not going to work either.

Why did they not just set the high pressure pump in the tank and call it a day like they did later in later years? Maybe they realized the vent (breathing) system in the bullnose truck tanks sucked big time.

[ArdWrknTrk]

You answered your own question...