I bought this truck new 1n 1990. The stop running problem started about 3 months ago.Maybe this is the time the fuse disappeared?? I removed a trailer brake switch that was mounted on the fuse panel plastic cover plate some time back .Maybe I knocked the fuse out ?

I have always got a read out on the rear tank fuel level .When i filled it with fuel it would read full. I have not monitored it all the way to empty? I will put a question mark ,is the tank gauge reading correctly ?I have had some changes in the fuel level read out in that tank ,and I just tossed it out of my mind.

Challe

 

my previous post about the fuel level gauge for the rear tank goes back in time when the front gauge stopped working, 1 year +.I only had this truck off the property two times in the last 3 months.Both times I had to have it towed in.
I did a little check on the fuel tank fuse # 15 position.
Fuse in place -ignition on - selected tanks -Rear tank full - F. Tank empty
The front tank is full of fuel!!!
Fuse Out -ignition ON- selected tanks -Rear tank empty -F Tank Empty
Looks like we have a working circuit.but no read out on the front tank????
Challe

 

I ran another check on the selector valve .I placed a voice recorder by the selector valve . Called out my moves and switched the tank selector switch from front to back tank.The play back was a very detectable swish sound when I switched tanks .Say swish with your tongue in the roof of your mouth. Ran this check two times, same results. Do you think the valve is ok ?? If the valve is ok what is the problem with the front tank gauge??

 

Yeah, that sounds good.
Maybe the float in your front tank fell off.

 

Some time back I called the Local Ford Service Manager about the sending unit for the tank, and he said they do not make this unit anymore , that I would have to find one in a junk yard??
challe

 

Do a "google" search.
"1990 ford f250 gas tank sending unit"
Ford F250 Fuel Level Sending Unit - Fuel Sending Unit - Motorcraft Action Crash Replacement Dorman - 1984 1995 1997 1996 1992 1990 1994 1989 84 95 97 96 92 90 94 89 - PartsGeek.com

There out there.

 

Thanks:What is involved in changing this unit .Is this a back yard project??
Challe

 

Ya, it's not that bad.
You have to remove the tank.
You may also find you'll need "strap's", all depends on their condition.

 

This sending unit surely is not the cause my truck stops running on me and will not start ?? What do you think ?? I think I will wait before I change ,at least until I get this other problem solved. I tried to start the truck up this morning and it ran for about 2 seconds and died. I ran the battery down trying to start ,no luck would not fire.How do you tell if the problem , Is lack of fuel-Air blockage-or electrical.
Challe

 

I thought you said you "fixed" that problem and was onto fixing the tank issue.

 

The sending unit not reading the fuel level will not cause your truck to die and not restart, unless you have run the tank empty. The truck starting and running foir 2 seconds, and dieing sounds like air intrusion. The most common place for that is the ruturn line o-rings. We have to get things sorted out to know where your issues are. Lets start by doing a fuel pressure, and flow test. To do this, place the fuel selector switch on the tank you know that is full of fuel. Next go to the engine compartment and locate the fuel filter. On the filter head there is a schrader valve, it looks like a valve you put air in your tire. If you press the center core in while cranking the motor, you should get fuel out of the valve. Take a cheap pencil type tire gauge and check the pressure there, you shoul have 5-7 lbs of pressure there. If that checks out, remove the core from the schrader valve, place a hose over the valve, and route it to a container, and crank it for 10 seconds. You should get 1/3 pint in this time. If either of these tests fail, the lift pump may be bad, or maybe the selector valve is bad. You stated that when you checked the selector valve that it did make a swishing sound when the switch was moved, so it probably is good. It can be flusterating if you have more than one problem, but you have to attack it one problem at a time.

 

I am sorry if I miss led you.I was hoping that I had the problem fixed by replacing the missing fuse. My plans are to fix all the problems on the truck,but I want to get the truck running first. Thank you for your input I really appreciate you taking the time to educate me . HI<>

 

I like your approach to my problems (plural) HI -I will try these tests tomorrow,and post the results.

 

Cranking the motor, ran the 10 second test with the schrader valve core removed ,put 6 oz of fuel into a container.
Cranking the motor, ran test with the center core pressed in on the schrader valve ,Moderate stream of fuel.
I ran the pressure test with a tire gauge without cranking the motor. No pressure read out.?? My helper had to leave so I did not get to make this check while cranking the motor.
Challe

 

Right, there won't be any fuel pressure without the engine turning.

-Matt