hey everyone, a quick question before we begin.

am i the only one that, even tho i literally have 8 other projects that need my attention, if someone says "Hey, do you want a truck?" i reply "yeah!"

Just me??? ok.


So i just became the owner of this wonderful piece of machinery. 1985 F250, 460/ 4 speed 4x4. pay no attention to the bed. i have a spare off my 91 F150 that i will use.



So i went to see the truck at the scene of where it died on the previous owner, a quick crank and it fired up for a few seconds, then died. i crawled under it, tank is dead nuts empty. i grabbed a fuel can and put a few gallons into the tank. once again, a sputter, then a die. ran to the local napa, grabbed a can of starting fluid, and sprayed it down the throat of the holley that was perched on top. the truck ran as long as i kept feeding it. finally, i unscrewed the rubber hose off the Holley and sure enough, not a single drop of fuel came out of the hose.

im calling that a dead fuel pump. if im wrong at this point, tell me.

Now, i leaned over the core support and was surprised to see no fuel pump bolted to the side of the block. i do believe i saw a block off plate, tho. i did, however, see an odd fuel filter looking contraption that had two lines coming from it, my only assumption would be a fuel and a return fuel line.

So, is this pump an electric pump in tank? is it frame mounted? i would have to assume, that with the truck running a carb, that the fuel pressure would have to be awfully low, my guess would be 8 psi or so?

im not looking to toss tons of money at this truck and do a full restoration. I intend for this to serve as a reliable beater as i keep squaring away my other projects. im just looking for a little heads up before i start crawling under the truck tomorrow.

 

First, you are not alone. In fact, that's how I got Big Blue, which is a brother to yours.

As for the fuel pump, while there were a few variations in that year, I'm pretty sure you have exactly what I have - in-tank low pressure pumps. And the strange contraption is a "vapor separator", which has a fixed oriface to return gas to the tank in order to keep the gas and the pump cool.

And, having just rewired mine back to stock I'm pretty familiar with the drawings shown here: Electric Fuel Pump Control - ???Gary's Garagemahal.

 

Thank you Gary. you've always been a helpful guy whenever a bullnose truck happens to wander into my care.

now, i should ask, the factory carb is long gone, and there is a Holley plopped on top, being fed from that single steel line above the Vapor separator. im guessing, since the truck ran this morning, that this is an adequate way of feeding the carb?

 

Yep. It fed the 4180 Holley that was on there originally, and it is feeding the 750 CFM Eddy on my truck. So it is adequate for the "new" Holley.

Be aware that the pumps don't like to work deadheaded, so don't do away with the return. And in the summer you may need the return to prevent vapor locking. That's why Ford went to that expense on the A/C equipped trucks. Heat from that big engine.

 

im gonna guess, there is a relay somewhere that should probably be tested first? or shouldi just pull the bed and get right to the pump?

 

Yep, there's a relay - or two. And switches. Power comes from the starter solenoid via a fuse link on the battery side and goes to a 2-pin connector beside the battery. Yellow wires come out and go into the cab where there's an inertia switch by the passenger's left toe, just under the carpet. Make sure that is reset. Then back to the 2-pin connector, across the radiator support, and back to a relay that is either in a plastic housing screwed to the firewall between the brake booster and the fender, or stuck to the fender itself if you have the trailering package.

That is the fuel pump cutoff relay, commonly called the fuel pump relay, and it gets pulled in by power in Run, but only when there's oil pressure, meaning the engine is running. The oil pressure switch is on the top/back of the engine.

But, the pump also gets power in Start via a wire on the I terminal of the solenoid. If you pull that wire, give it 12v from the battery, and turn the key to Run the pump should run. That bypasses the fuel pump relay.

 

Gary, you have the schematic on your website.

Pump power in run goes through the inertia switch to the pump relay.
The relay gets pulled closed by the oil pressure safety switch. (fuse #18)
When the relay closes, power goes through a resistor to the tank selector relay.
(after the resistor is where the blk/pink 'cranking' bypass wire is spliced in)
The tank selector relay defaults to the rear tank. (i.e. when not energized)

Some years have the resistor between inertia switch and relay.
Some years have the oil pressure switch making ground for the fuel pump relay.
But the basics are the same.

For troubleshooting start with checking power on both sides of the inertia switch. (Gary has nice pics of his wiring repair last week)
Then try jumping the oil pressure safety switch.
If the pump then doesn't run any time the key is on, the relay is faulty.

You know the selector relay and pumps are fine because the carb is getting primed while the starter is engaged.

 

ok guys, today was step one. i wanted to make sure the truck ran and drove before investing tons of time and money into it. look at this super awesome fuel system i whipped up in like 20 minutes, using parts i had around the garage. ( the fuel pump was new, for a thunderbird project i have)





2 gallon fuel tank feeds fuel pump, which has a filter screwed to it, and then feeds the carb. fuel pump is grounded and gets power via battery through the alligator clip. Yes, it is crudely ran, yes, i know i should have put it on a keyed switch with a fuse, but this is a TEMPORARY thing. i took the truck, drove it through all 4 gears, made sure it started, drove, stopped, the clutch was good, overall, im ready to keep moving on. Now, the truck will also lumber around the yard instead of being pushed everywhere.

Next step is to remove the bed and see what all i have to work with.

now, today's McGuyver antics got me thinking. what happens if i pull all the original fuel tank, pump and lines, use a new tank and sending unit i have had for years on a shelf ( 82 F150, its a shortbox tank, so only 13 gallon side mount) and ran new lines with this electric fuel pump? obviously, i would do a much better job of mounting and wiring the pump, but would it possibly be a better option than to go through the hoops of getting a new pump and tank?

the reason im thinking of a tank is judging by the exterior of the tank, im guessing i will find nasty-ness inside.

thoughts?

 

The 82 tank has a small mouth and the in-tank pumps won't go in. Sorry. Better by s new tank and use the existing pump.

 

perhaps, you didnt catch what i was asking. im suggesting using the 82 tank, ditching all the factory line, putting new hard bent line and the electric fuel pump i have ( the inline 8 psi pump) and just running it off of that setup. it would completely bypass the factory in tank system.

will the 82 sending unit read for the fuel gauge?

 

Yes, all the sending units have the same resistance range, so the 82 will work. And, your plan will work. I just didn't understand. But, at 8 psi you may have problems with some carbs. Edelbrock s don't like more than 5.5, although a Holley will take more.

 

good to know. i was thinking of swapping to an Edelbrock carb, so i will definitely take note of that.

I'm just trying to find the most cost effective way to get the truck on the road. a part i have had on the shelf from a long gone project from a decade ago sure beats dropping a solid 75-100 on a new tank.

 

ok, round two this weekend.

Started by using my rigged setup, getting the truck over to the shop, and cutting off the remnants of the bed.



Frame looked decent, i was happy to see that the shackles werent rotted off. there were remnants of a 5th wheel plate, those were removed. the rear tank had a corroded plug that had literally torn the plug apart, and had a baseball sized rust hole in the tank. so it was all taken off. the muffler was blown out, so it was removed. pulled off the twisted up DMI bumper, and pops spent a little bit of time just nipping off random brackets and bolts that seem to get acquired under a truck of this age.

then i noticed it.



the front tank fuel wiring was unplugged. i hooked it back up, and magically, fuel started squirting out of the fuel line at the engine. i hooked it up to the carb, the truck idled fine running off the tank. i could feel the tank humming away. a spirited 10 mile jaunt down gravel roads at over 70 mph proved that the plug wouldnt work itself loose, and also that the truck ran just fine.

I did notice that the gas gauge did not read. putting 8 gallons of gas in proved that the tank was not empty. i decided, for safe measures, to replace the fuel pump/sending unit at this time. Currently on order from Rock Auto.

so, two questions for you all.

First off, when deleting out a rear pump on an 87 to 96 truck, i typically use these "plugs" that i build out of old fuel pump ends, and fill solid with solder.



This stops the cross flow from one tank to the other that you hear about so often. Im assuming, since this truck has in tank pumps, a similar situation needs to be done? is there a better way to be doing the block off??

secondly, where is the fuel filter located on this truck?? i didnt see one, im wondering, was it part of the motorcraft carb, and whomever swapped it to a holley didnt put one on??

so yeah, the truck is looking better, running better. it also earned its name, Sanford.



Time to find a Ford emblem for the grille that doesnt need to be perfect, but at least somewhat presentable.

 

Hadn't thought about fuel coming back to the rear tank via a bad valve, but I did remove the rear tank so might ought to think about that. And, your approach should work well.

As for the fuel filter, I do think it was screwed into the Holley. My truck didn't have one so I added one.

 

will do. i will add an inline filter. i personally am a fan of the clear, glass center, rebuild able filters, i use them on everything with a carb, from my lawn mower to my massey harris to my motorcycles.