Hello All,

I have a 1983 Ford F150

I just replaced my tanks and new sending units, couple issues, the tank and sending unit that were in it on the front were not accurate the sending unit was not even close to the correct one, and the real was not even hooked up at all. So I bought brand new tanks front and rear, brand new transfer switch, brand new sending units. I have fully redone the the vent valves, although they don’t connect to anything yet cuz the vent container is missing.

prior to replacing these, the front tank worked no problem and sent fuel no problem. Only reason we replaced it was due to the gauge not working cuz the sending unit was incorrect. Now all parts are correct. But my issue is listed below.

since installing, I have put about 3-4 gallons of gas in each tank and turned it over to purge the lines, did this many times and nothing, so I went and rechecked the sending units and no fuel is come out of them into the lines, none. So it’s as if the sending units are not picking up fuel. I have removed the sending units while connected to the gauge electrical wires and the gauge reads full when float is up on both so I know the gauge and float work.

questions I have, do I need to add more fuel to be able to get the sending units to register the fuel? The gauge shows just above the E line.

Is the vent line not being connected up a problem causing the sending unit not to pick up fuel?

from what I have read I do not seem to have a fuel relay and if I do I have no clue how to find it as I’ve looked everywhere. Additionally, I also looked for an inertia switch and I don’t have one of those either from what I’ve read and how much I’ve looked.

is there a way to connect the two prongs on the fuel sending units to confirm they work? They are the direct fit replacements so only 1 wire inside the unit and up to 2 prong connector and up to the electrical section.

I can confirm that the sending unit registers to the gauge, but does not send fuel to the rail lines.

I am truly at a loss.

any help would be great

Front tank from drivers side

Front tank from passenger side

Rear tank setup

Transfer switch setup

 

3 or 4 gallons will register just above E in these 19 gallon tanks. Service manuals recommend filling new tanks, fuel lines pumps etc to half full for testing and to assist priming.

 

Okay, I will do that today and let everyone know. Thanks

 

You have an easy fuel system to work on.
You dont have electric pumps so no relay or crash switch.

What size rubber hose did you use?
It looks like 3/8 and that is the wrong size it take 5/16 hose for the fuel system.

I was trying to use 3/8 from pump to a gas can on the inner fender and would not pull fuel even with 2 clamps.
Put 5/16 hose on and it pulled fuel with no issues.

As part of my rebuild I replaced both senders.
Did you match up the old senders to the new to make sure they were the same and just as long?
Mine were the same.

Before I put any gas in the tanks I turned the key on and the gauge did not move for either tank.
I put 5 gallons in each tank and the needle came up to the E line. So when on E I still have 5 gallons left in each tank.
I did run 1 tank dry as I had to replace a float on one of the new sender and the tank did have some gas still in it.
I am thinking 3 or 4 gallons is not enough to reach the pick up tube in your case if the senders are the same as the old ones.

Also note that tank switching valve defaults to the rear tank with no power to it.
So if you added the gas to the front tank and it was on rear or you dont have power to the valve it will pull from the rear.
You can check for power at the valve. Test light or meter, key on switch to front tank no power to valve, switch to rear you should have power.
There is a fuse for the dual tanks so if no power check it.

So make sure you are using 5/16 hose and 5 gallons of fuel in the right tank.

Oh are you sure the pump still works?
Use a 5/16 hose from the pump to a gas can and see if it will pull fuel.
Dave ----

 

One of the advantages of having two tanks is that when you run out of fuel in one tank you can quickly switch to the the other tank. When that happened to me I took note of how much fuel it took to fill it and it was very close to 19 gallons. Filling the tank including some of the filler hose too. But when the needle just touched the E line I had about 3 gallons left. So my pickups were low enough, in the tank sump, to get most of the fuel out. This can vary of course vehicle to vehicle and sender to sender. Both of my senders are not working properly any more so I long ago went to using my trip odometer to keep track of fuel use.

 

I have them working now put fuel in the fuel bowl and it ran for a while. So seems to be doing the trick now, I’m using 5/16 hose, but I do note black smoke from exhaust now. Will that wear off after a while?

as far as comparing the sending units, I couldn’t as the old one was the wrong unit for sure.

 

Black smoke from exhaust could be other things like a carb issue. We would need more info, has the truck been sitting for a long time, what is the condition of the carb and ignition system.

 

She’s purring like a kitten now, no black smoke both tanks full, both tanks and transfer switch working. I did have to adjust the carb a little, the butterfly valve was stuck closed, I think when I put the coil spring back on the carb I didn’t have it adjusted correctly. So I fiddled some with it and now no black smoke and she sounds really good. Thanks everyone