kmpconley

I have a 92 F-150 with a 300 inline-6 that I can't get started. Truck is a single steel tank back by the spare tire rack. Sounds tragic, but about 5 years ago I parked it up behind my Grandpas barn after I bought my new F-150. The truck ran fine when I parked it, and prior to parking it, it had a brand new fuel pump installed. Anyone who's ever owned an early 90s model F-150 knows that loud humming sound that the pump makes when the key turns over without fully starting the truck, but it's no longer making that noise. Like I said the truck ran fine when it was parked, but I don't know how a fuel pump that was brand new at the time won't work. I've pulled the tank and tried to remove the fuel sending unit and pump, but couldn't pop the lines free. Either way, I'm still confused cuz it's not working. The tank has been cleaned inside and out, and is ready to be installed, but I still can figure out why the pump won't turn on. The fuel shutoff switch isn't tripped, I've checked it, but at the time I removed the tank which was approx 8 months ago, I couldn't get the fuel sending unit removed from the lines, so I took tie wire, and wired it up so it wasn't on the ground. No weather has gotten to the pump or sending unit, and the relays seem to be fine. I'm not 100% sure a relay fuse isn't burnt up, but when a vehicle is sitting and not being drivin, and without a battery installed, I really don't know how one can burn up? I've removed them, and they are not corroded, nor seem to be charred or burnt up. I've never had a history of electrical problems with the truck either. The motor will turn and turn but will not turn over and start. I bought a new tool to remove the sending unit, and new fuel filter, and will be putting fresh gas with intake cleaner in the tank, but without hearing that fuel pump kick on and hum like it always has, I don't want to install the gas tank again. Can anyone offer some advise about something I overlooked, or didn't do? Fuses all look good as well. I'm just baffled that a brand new fuel pump with virtually no drive time on it would just up and not work, even if it has been sitting for years without use.

Just call me Sean

iTrader: (1)

That's what they do, seize up when you don't use them.

Forge-World-FORD

Correct if I'm wrong Sean but can't you just jump two terminals together on the diagnostics plug and it will make the pump(s) run. Just can't remember which ones. If he did that would it help narrow it down?

kmpconley

I tried testing it like that. I hooked wires up to the fuel sending unit and I sounded like it wanted to work. Kinda a redneck way to hook it up, but i connected wires to it and touched the ends to the +/- terminals on a battery and it started buzzing. After that I tapped on the fuel pump and it losened up whatever was gummed up inside an started pumping. I placed it inside a half gallon of gas, and it pumped just fine and spit it up. Now I have it hooked up to the truck, and I'm not hearing it kick on again. I don't know what's goin on now. All relays are working. It's just not kicking on to prime.

Forge-World-FORD

If it works like that and you've swapped the relay and know its good then...trying to remember...I had a similar issue a couple years ago but my truck has dual tanks and my selector switch had fine bad..

kmpconley

Well mine is a single steel tank. So I don't have a selector switch. The main think I'm really wanting here is to hear the pump kick on when I turn the ignition over to accessory. That way I know it's working. A big problem is this truck is in my grandparents barn and I don't have a decent battery to start it. I'm trying to get it to fire up either with a battery charger, or jumping it from my other F-150. I'm wondering if I'm not getting enough juice, would that fuel pump not buzz?

Just call me Sean

iTrader: (1)

Yes you hook ground to a terminal on the diagnostic port to test the pump. I did have to clean my selector switch when I fixed my front tank.

Forge-World-FORD

Are you just not hearing it? When I replaced my front pump it was maybe a tenth as noisy as the old one, can hardly hear it. When you jumped the wires it made the loud whine like we all know? I need to find my book for the wiring diagrams. I have some stuff to do but I'll try to look some stuff up for you.

Just call me Sean

iTrader: (1)

You're really not supposed to hear the pump, just barely. When they're noisy they are on their way out.

kmpconley

Well my next step is to check the wiring harness with a test light, and see if I'm actually gettin power through the harness to the fuel sending unit. It just blows my mind how it ran when I parked it, now it's not. Especially now that I know I had the fuel pump working. If I'm not getting power to the wire harness that connects to the fuel sending unit, where do u think I should look for that problem?