Husky55

First post. Just started my first project. I picked up a 1984 302 F150 4x4. The truck has been sitting for the past 4 or 5 years. She cranks, but is not delivering fuel. Siphoned out the old fuel, put in fresh. I tested the fuel pump, found it was bad, and replaced it with a new one. I put the outlet line from the pump into a pan and got maybe two good pushes of fuel when I cranked the engine and that was it except for a drop here and there. It seems the problem lies between the tank and the pump. There is no leaking going on from the line to the pump. I am a little confused on the tank as I have heard there may be different styles of sending units and also a filter in the tank that can easily get gunked up. Any advice or knowledge is much appreciated. Thanks.

-Ian

TruckPastor

explain a few more things first...did the engine fire up and run for a short while with fuel line in separate gas tank or not? My 84 only has a mechanical pump bolted on the block. is that what you changed? But I also would go ahead and change every fuel line from tank (or tanks like mine has) since it's sat for so long...they are either cracked or mark my words WILL CRACK soon if not changed. How is your carb? If that's been sitting for 3-4 years...you must rebuild it for it to run right. or go aftermarket like my Holley street avenger!

Roger Mabry

My '84 truck had a crack in the rubber line and it "starved" under a load. See the picture...the advice to change out ALL the rubber fuel line is solid.....

Husky55

Yes, the mechanical pump on the side of the block is what I changed. I poured a little gas down the carb to see if the engine would fire and it did, obviously only for a split second as the gas was not coming through the fuel line. I will check all of the lines, been a lot of rain here and haven't worked on it in a few days.

Roger, where was that cracked part of the fuel line on your truck?

Is there a way to simply bypass the dual tank valve in the back and have it run off one of the two tanks?

TruckPastor

It is sounding like a clog in the lines from gummy gas. I've had a complete blockage before. And while you are changing lines buy an inline fuel pressure gauge and put in post pump.

Another idea comes to mind is that you possibly didn't get your fuel pump arm under the cam lobe properly. Just my 2cents

Roger Mabry

My cracked line was between the fuel pump (I changed mine as well and
the questions about the fuel pump arm should be considered) and the firewall where the steel line comes out.

To separate the fuel system parts and resolve the problem(s):

You should put a long piece of hose from your new fuel pump, crank with a fully charged battery, with the other hose end in a can of gas. You should get a lot
of gas (most of a pint) from the pump in just a few seconds = if not, the pump is not working properly and you can discount the rest of the system at this time.

If you get proper gas flow - hook the hose to the carb and see if it will run from the supply in the can of gas....if so = engine and fuel pump is fine
and the problem is "back there somewhere".

Husky55

Update: From what I can tell my fuel system is fine, I believe I may be having an instillation problem. If I hook up my pump to the inlet and outlet lines, I can manually pump gas through the system. But once I install it, it no longer pumps, as if the rocker arm is not being pressed down correctly. I know you have to get the arm under the shaft, but is there maybe a trick to this I am missing and some how getting the arm above the shaft? Or could I possibly have a bigger issue inside the block?

GhostriderI

Trick I use. As you install the pump place the arm at the bottom of the hole in the block (hold the pump at an angle if you need to, to get the pump arm down) this gets the arm under the cam, then line up the bolt holes and finish install, I forgot to tell you hold the gasket with the pump when inserting the pump in to the block, then connect the fuel lines.