Hey guys, I drive a 86 F150 with the 300, and this morning I was greeted with this.

10 bucks worth of gas spilled on the floor.
Scared I had a fuel tank leak, I quickly got under to inspect.
i then found this.

Looks to be a fuel line?
after doing some research, I found out that it belonged to my fuel reservoir, and seems to control the front tank supply. I however, could not find a possible place where this line would connect. Is there something I’m looking over? Any help is appreciated, thanks.

 

If you have a 1986 with a 300 six cylinder, why would you have a fuel reservoir? Only the fuel injected trucks had a fuel reservoir. Has the 300 six been swapped in place? Do you have dual tanks? Or I should re-phrase that; Did you have dual tanks?

 

maybe my terminology may be wrong, but then what's the pump/filter thing that's has all the blue fuel lines connected to it?
And yes,. mine came with Dual tanks as stock.

 

If you have a stock 300 six truck with dual tanks, then you have a switching valve on the frame, no filter, no pump. The fuel pump is mechanical and on the engine. Maybe you had better take a picture of this filter/pump device you have.

You should have one fuel connection on each tank, and then 3 connections on the switching valve.

 

It appears to me that the little plastic clip that keeps the fuel-line connected has deteriorated and left the scene.

A plain old zip-tie can be threaded through the little holes and will keep things together until you can get a proper clip.

It is also possible that someone knew enough to remove the clip, disconnect the line, and let your gas pour into a bucket; if that be the case, then the missing clip may be somewhere on the ground.

 

Auto parts stores will have clips for those lines. If you need.
https://www.google.com/search?q=ford...hrome&ie=UTF-8

 

How did this story turn out; what did you find ?

 

well, after a bit or searching and looking at some diagrams, I’m led to conclude that the loose line is a part of the dual tank fuel system in my truck, and the line hanging WOULD be connected to my first tank, but upon further investigation, I found the first tank was routed directly with a separate line, leaving the dual tank system useless. Following the lines, I found another end of the fuel system capped off with a rubber cap. The line leaking seemed to have been tucked away when it was disconnected. And didn’t leak since there was no gas in the rear tank. However, I come along, and give it $20 worth of gas, unaware that this line was open, and in return spots out that gas a few days later.

I guess this also explains why the real tank always read empty when switched.
In the end, I ended up draining the rest of the fuel in the rear tank, and capping off the line, essentially rendering the rear tank useless. i DO plan on reconnecting everything in the future though, but for now. It’ll remain unoperable, and besides, I don’t do much long distance trips either, so there would be little to no use for it regardless.

 

I am going to surmise that the reason the fuel selector was bypassed and the truck is running off a single tank is on account of the previous owner getting fed up with the fuel tank selector failing and running him out of gas in busy intersections.

Way back when my truck was nearly new, after the fourth tank selector stalled me out and near got me killed, I installed two manual selectors, one for draw and the other return, and put the gauges on a double-throw toggle switch.

If you do opt for manual selectors, don't get misled into using the ones that include ports for both draw and return as the skinny stem is having to turn two ball valves instead of one and will soon snap off between the two valves (bad) or just above the top valve (worse).

I would not have another O.E.M. selector put in my truck with a gift of $500 along with it; that is how little confidence I have in them.

 

I guess it depends on how you use your truck, me, I don't have a need to carry more fuel, "weight" around.

 

I wonder why there's such a quality difference in the switches. The previous owner of my truck swears it's the original switch. He has owned the truck for the last 20years. My fuel switch works fine......until now that I have Jinxed myself. Haha

 

My ruck was 2-yrs old when I got it, so I have no idea whether the switch that came in it was it's first; I do know that every failed one thereafter came from the local Ford garage in genuine Ford boxes.

My truck has always been diesel; maybe it is a diesel thing; I do know that diesel will destroy a gasoline-rated fuel line within days; so, maybe Ford does not make sure their switches are compatible with diesel.

 

I wonder if it's more that your switch is use weekly as to one that maybe has sat for years...not used.

 

For the OPer if your truck is a true 300 six truck and not a motor swap from a v8 to the six as DaveF? said you should have a easy system to figure out and fix.
The 300 motors used carbs so no return fuel lines only supply to the motor driven pump then to the carb.

Now there should be a 3 port valve on the frame rail in front of the side tank, kind of under the drivers butt.
I think with truck off , key on and not a lot of noise you can hear the valve click when the switch is moved.
The 3 ports are 2 inlets = 1 from each tank.
1 outlet = to the motor driven pump.

This valve only has 1 electric wire going to it and the valve is grounded when bolted to the frame rail.
This valve defaults to 1 port, on mine it is the port marked "rear", so no power to valve it is on the rear tank.
This can become an issue if the switch is on the front tank and the fuse blows for the fuel valve.
The gauge still reads the front tank as that is what the switch is on but no power to valve defaults to rear and will be pulling fuel from the rear tank.
I was lucky as the rear tank was full and I did not see the front tank level dropping for the driving I was doing.
I then switched to the rear tank and found it was no longer full.
When I was running wires for trailer lights I shorted the fuel valve wire and it blew the fuse and why no power to the fuel valve.

Yes it is that simple

BTW being I have a flare side they never came with dual tanks so I added mine.
Flare sides are short bed trucks and they only come with a 16 gallon front tank, no rear tank option.
I added the 19 gallon rear tank and vary happy I did because if I drive my truck to / from work for the week that is 400 miles and on 16 gallons I would need to stop and fill up a lot more.
Dave ----

edit: I did not know the later 300 six trucks used plastic fuel lines and mine are metal the use short rubber hose & clamps to make connections.

 

Many times, my tanks would get switched several times per day before I added the 52-gallon auxiliary; now, that always gets emptied first, keeping the two little tanks in reserve, so they may get switched once per day depending on where and how far.

Back in my gas-burner days, I did this same work with only a puny little 16-gallon tank; I spent more time at filling stations than I did driving; I carried two Jerry Cans and resorted to them often.

Then, a friend showed up one day with another tank, brackets, fuel selector, and all for the other side of the truck and I felt like I could head to Alaska and get halfway back before worrying about fuel.

Now, if 32-gallons was all I had, knots would be in my belly all the time, worrying about running low.