My truck has dual tanks. the midship tank works but the rear tank does not. It was like that when I bought it.
I would like to replace the fuel pump as I am almost positive that is my problem. Would it be better to try and remove and replace the pump or just replace the whole hanger assembly/pump?

Thanks.

 

I looked in your other post and as a reminder to everyone, he has a 1983 f250, 460 with a carb.

Ford sending units are not known for the longevity, but the whole assembly is 3 times the price of just the fuel pump. So it's your call. Just make sure the sending unit works the gauge before you put it back together if you get the pump only. I also saw where they would not warrenty the fuel pump unless you bought a new strainer too. The whole assembly comes with the new sending unit, and strainer.

 

About $140 for the whole unit to ?. Depends on what brand of pump. Right?
Can I check the sending unit/gauge by grounding it to the truck frame? Won't it jump the gauge to full? I would make sure that the gauge works before I make my decision on what to replace.

 

Yes, you can plug the unit back in when it's out of the tank, and run a ground wire from the unit to the frame. Turn the key on, and as you move the float up and down, the fuel gauge needle should move smoothly up and down(make sure you have the switch to the rear tank).

 

The 1983-1985 7.5L Electric Fuel Pump Control is a very complex system, it is not like any other.

What makes you think that the Rear Fuel Pump or the sender is bad?
Have you checked is fuse? (#15 10A)
Does the Selector Valve Switch Motor run?
Does the Fuel Gauge change any when you change tanks?
Have you looked at the Tank Selector Relay?
Besides all above the above you also have a Fuel Tank Selector Switch but it is more than likly good.
Other items you have in this system are:
An Oil Pressure Switch for turning off the Fuel Pump Relay.
Inertia Switch for cutting power to the Fuel Pump Relay.
Fuel Pump Relay that feeds a 0.75 Ohm Resistance Wire.
A Diode, two fuses and two fuse links all for power for just this system.

And no you can not check the float unless the motor has ran the Fuel Selector Valve Switch to the rear tank position for the gage to read the rear tank.

I will see if I can post a Diagram of this system, the Duraspark II Ignition was a much simpler system than this one.

 

Here is the diagrams, sorry about the water spots they were behind my seat in my 1983 for 20 years.

 

Your right subford. I don't know for sure it is the pump/sender. I am going to do some tests with the voltage meter/light on the brown/white and yellow/light blue wires before and after the selector valve to see if I have current going to the pump and sender.
Thanks for the diagrams. Those will come in handy.

 

I did a couple of tests last night with my test light just checking for current going to the tank selector valve on the frame. I am getting from the brown/white wire just in front of the valve. I am also getting flashing light current on the yellow w/white wire which according to the diagram is the fuel gauge wire from the selector valve.
I would like to lower my rear tank enough to get the wire harness connector off from the top of the tank so I can check for current there before I take the tank all the way down. If I am getting current to both the pump and the sender I am going to assume that just my pump is bad. Then I will only have to change the pump and strainer instead of the whole assembly ($).
Does this sound like I am on the right track?

 

What are you getting on the other side of the valve on the frame (pin 5, yellow wire with a lt. Blue stripe) going to the tank with that tank selected at the dash?

What are you getting at the Brown wire with a White stripe at the tank selector relay with the rear tank selected at the dash?

If you are getting flashing light current on the yellow/white wire at pin#5 and if you are getting power on the Brown wire with a White stripe in the above tests and if you have a good ground at the tank then the pump and sender are bad.

 

When you say "In the above tests" do you mean the ones that I did or the ones that you suggested?

What would a good sender test look like?

Thanks

 

The ones I suggested.
It should be a flashing test light or a reduced voltage on a VOM.

 

So are you saying that if the test light on the yellow/white wire is flashing than the sender is good or bad? I am confused

 

If it is Flashing then you have a signal to the sender. If the ground return wire from the tank to ground is grounded and the gauge does not say what it should on this tank but it does read right on the other tank, then the sender is bad.

Do you have a copy of the above prints?
Let me know and if you do then I will drop them from the post.

 

well the gauge does not read right in my front tank either but that is a new assembly. I think maybe I put the wrong size in it. I bought an assembly for a 22 gallon midship tank instaed of a 19 gallon. I don't know if that will effect the float movement or not. Maybe my groung is bad!?
I do have copies of the above.

 

If any one needs to look at the above missing diagrams goto:

http://i54.photobucket.com/albums/g9...d/Fuel/837.gif

http://i54.photobucket.com/albums/g9...Fuel/837-2.gif