Hey everyone, this is my first post on the forum. I really do like FTE. All of you have been really helpful.

I don't know much, but I'm absolutely willing to be corrected and take criticism to solve the problems my vehicle has.

Vin: 1FDJS34L0HHB14884

I am a college student. I purchased an 87 E350 McCoy ambulance. It's like a time capsule, seriously. It's like new. The inside has almost no wear. It's got 17000 miles on it. (Im the cynical third owner, I confirmed the mileage. There's no way the interior and exterior would match 117,000.

I bought the van to take me to work. The plan is medical school, so I'm also outfitting it to live in full time to save money.

I bought it from a veterinary clinic. They bought it from a fire dept in nebraska.
They (the vet) have run it infrequently.

What they did:
Rebuilt carb
replaced some hoses and belts.
Changed oil

What i've done:

To help
Hard ignitions:

replaced fuel filter

Replaced battery
Changed plugs (all 8 were old, sooty, same across all eight. No noticeable differences (Motorcraft platinum.)

Symptoms now:

In retrospect, the van ran out of gas because it pumped all of the gas to the nonfunctioning rear tank through my selector valve. I know this for a fact. I removed both tanks and senders. The rear tank took all of my good gas.




The insides of the tanks are really clean and nice, even the rear one which wasn't really used in a long time.

I completely removed the selector valve. I cut the 5 wires going to it.
(I have return lines btw. It was the 6 port. )
I spliced a transparent valmar marine fuel filter inline. I'm only going to run on the front tank.

I ordered a new hanger assembly with the fuel pump and the sender from Delphi through Autozone. I cleaned the tank of minimal particulates, and removed rust and primered the top half. I installed the pump in the tank.
I reattached everything. The tank is up in the van. I put 3 gallons of gas in. I estimated that amount to reach the strainer; at least start it and get it to a gas station 3 miles away.

This is what I did next.
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I don't know what the electric diagrams are. I assume that the selector valve also acts as a switch to turn on the fuel pump.
I would alligator clip 2 wires together on the fuel tank switcher valve and then turn the key in the cab to see if the pump would pump fuel through the line.

I tried every combination of wires and no power is going to the fuel pump. I've been broke down for 3 weeks and my boss is concerned because I need the transportation to work.

I know I could just run a wire directly to the pump but if the engine does not have oil pressure for some reason then I don't want to override a safety feature.

More details:

There is air in the lines. There is not an unbroken column of fuel.

I am on an incline.

The battery needs charged.

Any help would be very appreciated. I know I will figure it out eventually, but I hope eventually is tuesday.

Thank you all very much. Please correct me if I am wrong.

Thanks,

Zuczis

 

It would be helpful to know what motor you have. This is a wiring diagram for a 460 carb motor with dual tanks.

You can jump power from the hot post of the battery to the small wire attached to the I terminal on the starter solenoid and the pumps should run but this is NOT a long term solution. The pumps were not designed to run a full 12 volts continuously and you will eventually burn something up if you do.

The main fuel pump power circuit for the 460 starts at the starter solenoid. It is attached to the large hot post of the starter solenoid through a 20 gauge fusible link and you should check the fusible link to see it it's burned out. Next it goes through the inertia switch and then to the fuel pump relay.

The main wire from the starter solenoid to the fuel pump relay should be hot all the time. If it's not, you have a problem.

Also, the fuel pump does not cycle when you turn the key to run. Fuel pump only gets power when cranking or with the motor running.

 

Thanks. Actually what was wrong was that I hadn't turned it over enough for fuel to actually go up the lines.
I drove it home that day.
It broke down again.
I went through the whole ignition system. Found that it was the module. I replaced it. Now it starts very well, almost immediately.
when I turn it off and it's warm all i have to do is bump the key. BAM!
Now I'm having another problem.

My oil pressure gauge is not functioning.

It's worked in the 6 months I've had the truck. I'm sure it worked for the vet clinic.
First sign was when I was driving it home after fuel system fix. I didn't see it, but when I looked at the dash I saw the gauge had bottomed out. I shut the engine off immediately.

I then did a test. I unplugged the fuel pump oil safety under the sender and I started the truck again. It died under the simulated loss of oil.
I then drove the truck home. The gauge started working again.

I just recently found the root of the hard starting. I did an ignition system test, ran through all the components. It was the ignition module.

I replaced that and now it starts almost immediately.
Anyway, more on the sender:

I drove into town and the gauge stopped working at oreily's after I shut the truck off.

I started it again and noticed it. I shut the truck off.
I did the simulated no oil test. It behaved accordingly.
No valve train noise.
I think I drained all the fuel out of my bowls. I went to leave, and the truck died. I then called a tow truck. I got it towed to my apartment complex. I'm about to go work on it.

The sender is original to the truck. Could it have failed?


Symptoms:
Gauge non-functioning, has stopped working twice.

No low oil noises (valvetrain sounding like percussion section)

Died when I drained the bowl.

 

Not hard to replace the oil pressure sender and yes they simply do go bad.

To prime the fuel system. You should have a small wire attached to the small I terminal of your starter relay. Jump 12v to it from the hot side of your battery for about 5 seconds and you'll have enough gas in the carb to start it.

If you accidentally jump power to the small S terminal you will trigger the starter to engage.

 

Yeah I think it's the sender too.

Also, I can disable the fuel pump through the inertia switch, right?

 

Correct. except the fuel pump will still get power only when the starter is engaged via the little wire attached to the small I terminal of the starter solenoid.