1978 F150 Custom, 300 I6.

Hey folks, recently I replaced the instrument gauge cluster on the truck because the crummy "plastic" backing crumbled. I ordered a used one from Bronco graveyard. I didn't see that it was used, but oh well. I messed up some of the threads on the old fuel gauge and just installed the gauge that came with the "new" cluster. I'm guessing the cluster came from a Bronco because the speedo read up to 100 mph and my old speedo went up to 80-85. So I'm thinking this gauge I installed has a different resistance than the old one. I was at a 1/4 of a tank today, went to fill up and only filled in 11 gallons. It's a 22.5 gallon tank. So my gauge is way off! Plus after I filled it, it read way past full. So does anyone know where to get an appropriate gauge? I have looked online a NPD, Dennis Carpenter, Bronco Graveyard and NAPA. No one ahs anything. Any suggestions? Thanks for the help!!!

 

Fuel gauge, use with unleaded fuel only, orange pointer
D7TZ-9280-B
Wesley Obsolete Parts has 3 (606) 787-5293
Green Sales has 3 (800) 543-4959
Larry Allen Motor Co has 1 (620)421-0100
NOS Parts Source has 1 (913)220-5746
Sanderson Ford has 2 (623)842-8762

 

D7TZ-9280-A Use with leaded fuel
Wesley Obsolete parts has 5
Green Sales has 2
NOS Parts Source has 1
Sanderson Ford has 32 (!)
Collectors Auto Supply has 22 (800) 414-4462
Parts International has 1 (888)727-0418

 

Thanks Mike, but neither of those parts #'s match to the one on my old gauge. The number on it is D3TF-9306 N.

 

The number on the gauge is NOT a part number, its an engineering number. Ford hasn't put part numbers on parts since 1956.
I looked the part numbers up in the Ford parts catalog.

 

They changed the speedometer from 100MPH to 85 MPH in 1977. The idea behind this was if you didn't know how fast you were going, then you would be less likely to speed, therfore use less fuel. The 55MPH national speed limit, 85 MPH speedometers, etc... all came from concequences from the 1973 opec oil embargo.

 

I actually have the same issue on my 78 F150 Custom 4x4 back here in Sweden, sending unit seems OK, fuel gauge "dead", needle does not move on ignition-on.

Saw that you provided two different part numbers (leaded / unleaded fuel) for the gauge (are the sending units different, too?), how do I determine which one I need on my truck?

I also have an issue with the ampere-meter, doesn't work at all, wiring seems to be OK....

 

i have the same issue with a brand new sending sending unit, reads about 1/4-1/8 tank and its really about 1/2 way. i have a 19 gallon tank...

youll never run out of gas as long as you stick to your guage!

 

There is a guy in Canada with some NOS Gauges for sale if your interested

 

D7TZ-9280-A
D7TZ-9280-B

The only differences between these two gauges is one has "Unleaded Fuel Only" written on it and the other doesn't.


Take the wires off of the sending unit and ground it momentarily with the ignition switch in run. The gauge should peg. If it does peg, then it's the sending unit or float.

The most comon problem with fuel gauges not working is the float in the tank springs a leak and it sinks to the bottom of the tank. These floats are changeable and still avaliable at ford.

The sending units are different depending on what capacity fuel tank you have, or where it's located. Either in-cab, mid-ship, or aft axle tanks.

 

Thx guys, will do the grounding test and come back (still suspect the gauge since somebody tried to hook up the radio looking for 12V "somewhere" under the dash, since then the gauge is dead....

 

You can bend the sending unit float arm to correct for that if you got the right sending unit in the first place. Or you could have accidentally bent the float arm when installing it. Bending it up will make it read less, bending it down will make it read more. Etc...

 

Hmm, could be the wiring, if they snipped it.

It could also be caused by Instrument Cluster Rot Syndrome. Where the plastic of the instrument cluster desentegrates. If the cluster was crumbling, and they were moving wires about, etc...

From the instrument cluster connector, there is an Orange wire, for the Fuel gauge. This wire will change color to either blue wire or Green/red stripe or Green. If you have dual tanks it will stay Orange and go to the fuel selector switch in the dash.

 

The gauge in my 1977 used to peg WAY passed the full mark and the truck would run out just before it hit E. Most vehicles you can run down passed the E quite a ways. I just carefully bent the needle way at the base and out of sight. Problem fixed.