Fuel sending unit/gauge woes

[Sweetblu]

I have a 1972 F-250 Ranger XLT I just picked up (Been wanting a ford for a long while) and she is a beaut, but has a couple minor issues to work on. The one I am asking for some help on here is the fact the fuel gauge does not work. I started with what I see all over the site here and figured I would check to see if grounding the incoming wire to the unit would peg the gauge. Well.... It didn't, and, it made a spark when I did and the amp meter took a little dive while doing so.


What should I be checking next? I followed the wire (Orange) up the side of the back, and over the door and then I lost it as it went down the front pillar. I know it isn't shorted any where because then there would be a spark I assume. But it seems as if it is getting TOO much power being sent to it. What would cause this and is the gauge or sending unit damaged because of it?


Looking forward to any help my fellow ford enthusiasts can offer me here.


Oh, also, the dash lights do not work, not sure if it is related or not but that is the only other electrical issue I have with her.

[Sweetblu]

Oh, on a side note I need to replace the tank filler line from the cap/ Anyone know what size house that is?

[terry1167]

Welcome from Colorado Sweetblu! 72 F250 XLT's are awesome. I too had some gauge/cluster problems and still haven't gotten the fuel gauge to work but I just havent had the time. Way too many projects going on but I do intend to get back to it.

Here is my thread on the gauge issue. LOTS of help from members and it really did help me narrow it down. Take a look at it and go through the steps.
http://www.fordification.com/forum/view ... =8&t=56090
Good luck!

[Sweetblu]

Thanks for the welcome and yes, they are pretty sweet trucks!

I have looked over your thread and the fuel sending unit troubleshooting page as well. The thing is that my issues isn't covered there. when you look at the troubleshooting tree it says if you don't peg the meter when you ground the orange wire then you don't have power being sent to it. And I do have power... Enough to make a good spark, and to pull the amp meter on the dash to the left half way.... Is this an issue with the ICVR?

[Sweetblu]

I have been digging more, and I see some mention about dual tanks and switches going bad... I do have dual tanks, but everyone refers to the switch being on the dash while mine is on the floor by the seat and door... Is there another one for the gauges??? Is that one just for the fuel lines??

[fordman]

on dual tank trucks they ahd a switch on the dash and on the floor. the siwtch on the dash was to switch the fuel gauge only the floor switch is to switch lines from each tank. if you have the factory dual tanks.

[terry1167]

Thanks for the welcome and yes, they are pretty sweet trucks!

I have looked over your thread and the fuel sending unit troubleshooting page as well. The thing is that my issues isn't covered there. when you look at the troubleshooting tree it says if you don't peg the meter when you ground the orange wire then you don't have power being sent to it. And I do have power... Enough to make a good spark, and to pull the amp meter on the dash to the left half way.... Is this an issue with the ICVR?

I too did the trouble shooting tree and did not peg the meter so I had to figure out where the "break" was. I bench tested all my gauges with a 9 volt battery and the fuel gauge DID peg when I did that. I also tested the connector by plugging in a different cluster and the same thing, so in my case, the problem is in the wiring to the cluster. I also bench tested the IVPR. I also tested my dash switch. In my case, the problem is in the orange wire. I just haven't taken the time to test the wiring. If you look at my thread, it mentions testing the dash switch too by the moderator, Thunderfoot. Good luck and keep us posted!

[Sweetblu]

Well, do you also get a spark? I do not think I have a "break" somewhere because if I did it wouldn't spark because it wouldn't be live right?

Where would the switch on the dash be located?

I will try to figure out how to attach pictures and if I do you will see them here:





As you can see I have NO dash switch ( that little thing right next to the door is a light right? It doesn't work though, none of my dash lights work ), or anywhere one would be (no empty hole ) and it seems like the install is the factory one switch-wise. But even if it was after market wouldn't they also put a switch on the dash?

[forrestbump]

The factory fuel gauge only toggle switch should be mounted almost directly under the ignition switch on a steel mounting plate bolted to the bottom lip of your dash board.

The tank switching valve shown in your picture seems to be the O.E.M. valve. As far as if this is an after market installation, it's possible that the fuel gauge toggle switch was not part of that installation.

To help confirm that yours IS a factory dual tank Bump, more pictures of the tank, fuel filler hose, location on the side of the bed of filler inlet will help. Or it's also possible that the PO removed the toggle switch from under the dash.

[Sweetblu]

I will get pictures of the tank and filler and whatnot tomorrow.

If I need to, how hard is it just to run the needed wires from the gauge to the tank myself? What is needed and what do I run from where to where? Is there a guide already for this?

[forrestbump]

Pardon me, but I'm old and my memory is not as good as it once was...

Back in the early 70's I put two saddle gas tanks in my old Bump (new at the time) that only had the in cab tank. I bought a three position electrical switch for the switching the factory fuel gauge. I simply spliced the wires from the gauge into the after market switch and ran wiring from the saddle tanks to this switch.

Most electrical switch vendors will have a wiring diagram outlining how to make it all work. Check online and see what you can find.

Godspeed...

[fordman]

which tank do you have from this page. http://www.fordification.com/tech/fueltank01.htm

[Sweetblu]

I have the one with the filler below the belt-line(fig 4), and it has the exact same cover thing in the bed of the truck(fig 2) and just like in the other pics there and how it is described where it gets in the way of the dual exhaust so both go down the passenger side. It is in the middle of the rails and has a metal cover over the bottom.

[forrestbump]

That confirms that you've got a factory dual tank Bump. Now as far as your missing electrical switch, is there any evidence of cut and dangling wires on the left side of your dash? If so, they probably belong to the missing switch.

Do you want to install a factory correct switch? If so, either ask Fordman, our resident guru and the best parts supplier for Bumps known to man or place an add in the classifieds here under parts wanted.

[Sweetblu]

I am planning on removing the second tank as some PO cut the lines and has bypassed the fuel switch on the floor anyways so all I want is the gauge on the main tank to work .


And as for something missing, there is a hole on the bottom of the dash where maybe something was attached but I see no wires.

How hard wold it be just to run new wires?