fuel gauge not working
Thread Starter
|
Senior User
Joined: Nov 2010
Posts: 218
Likes: 2
fuel gauge not working
i just got this truck and the fuel gauge not working. reading empty. and i know i just filled 1st tank up. it has 2 tank. i put 5 gal in other tank both show empty. someone had put a new gauge down low, that not working either. i do a video in morning so you see what iam saying. . i just had the plugs changed wires belts cap rotter points conds. was going to store it acted like it was bot getting gas. i did not smell any gas, its a 4 speed 360 1974 2 wheel drive.
Freshman User
Joined: May 2011
Posts: 30
Likes: 0
Sounds like your fuel sending unit or the float inside the tank is stuck or maybe corroded...especially if the truck has been stored or not run in a while. You might need to drop the tank(s) and check but I would do just one at the start and see what you find first.
Cranky Old Guy
Joined: Mar 2008
Posts: 3,562
Likes: 6
From: Raphine, Virginia
You can ground the sending wire and gauge should peg. If it does, bad sender. If not, either gauge or wire between them is bad. With two tanks, I would suspect the switch. Grounding the sender wire also works testing oil pressure and temp gauge.
Senior User
Joined: Jun 2011
Posts: 146
Likes: 0
From: Bristow, VA
Since you have a dual tank set up, I would be surprised if both floats in both tanks were stuck (still possible). Could be a sending unit, but then again you would have one in both tanks and for both to be bad (also highly unlikely. Deffinetly electrical problem, but before you start dropping tanks and replacing guages, I would do what gfw1985 suggested with grounding the guage. If it pegs full then not the guage or a fuse. Tace the wire from the guage to each sending unit. I am guessing you are grounding out since neither sending unit in either tank is working. (Check where the new guage was installed.
Thread Starter
|
Senior User
Joined: Nov 2010
Posts: 218
Likes: 2
i added a video on youtube, YouTube - ‪1974 Ford F-100 Fuel Gauge Not working‬‏
Senior User
Joined: Jun 2011
Posts: 146
Likes: 0
From: Bristow, VA
The black wire seems to be the ground and the red lights I believe are indicator lights to let you know which tank is in use. It lookes as if the guy has wired the guages using the wires from the original guage and added the lights, not sure why, because if set up correctly the one gauge should read empty when the other tank is being used. Lookes like the wiring is the issue and I dont think your guases are ground properly or wired correctly. Disconnect the lights you won't need them and wire the gauges directly to the switch. Whenever you see the gauges dip the way the one on the left did when you turn the key it is because you have a grounding issue.
Trending Topics
Senior User
Joined: Jun 2011
Posts: 146
Likes: 0
From: Bristow, VA
Another option is to connect one guage at a time. I would start with the one on the left and reverse the wires so the guage moves to the right. I am almost positive that the guy crossed the ground with the common and that is why your guage dips.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Thread Starter
|
Senior User
Joined: Nov 2010
Posts: 218
Likes: 2
i may have fixed it. 2nd youtube video YouTube - ‪1974 Ford F-100 Fuel Gauge Part 2‬‏ when i turn **** on floor change tank nothen happens. but if first tank reading right i can deal with that for now, thanks for all the help out there,
Senior User
Joined: Jun 2011
Posts: 146
Likes: 0
From: Bristow, VA
Looks like the wires were crossed and the ground worked, glad to see it was something simple. As for the guages not working when you switch between tanks, that is because the way it is wired also. The originat switch in the truck is designed for one guage to give a reading for whichever tank you are using. My guess it the install of the second gauge is not working properly because the gauge is not directly wired to the second tank. I would bet that if you switch between tanks the gauge on the left should reflect the gas you have in the other tank. When you switch between tanks, does the guage on the left go down?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
The fuel sending unit float is made from two pieces of copper soldered together.
Solder breaks down, gas seeps in, float settles to the bottom of the tank.
COAZ-9202-B .. Fuel Sending Unit Float / Available from Ford.
Fits ALL: 1957/79 Passenger Cars/Trucks, 1961/79 Econolines & 1966/79 Bronco's.
-------------------------------------------------------------------------------
1973/79 F100/350 with dual fuel tanks: There are two different fuel tank selector valves.
1973/74: The valve is manually operated, mounts on the floor adjacent to the drivers side of the seat.
A switch is mounted within the heater control panel. This is only used to switch the dash fuel gauge from one tank to the other.
---------------------------------------------------------------------------------------------------------------------------
1975/79's use an electric fuel tank selector valve and solenoid assy. This valve is mounted on the left (drivers) side frame rail.
The switch is located within the heater control panel, changes the fuel tanks and the gauges.
Solder breaks down, gas seeps in, float settles to the bottom of the tank.
COAZ-9202-B .. Fuel Sending Unit Float / Available from Ford.
Fits ALL: 1957/79 Passenger Cars/Trucks, 1961/79 Econolines & 1966/79 Bronco's.
-------------------------------------------------------------------------------
1973/79 F100/350 with dual fuel tanks: There are two different fuel tank selector valves.
1973/74: The valve is manually operated, mounts on the floor adjacent to the drivers side of the seat.
A switch is mounted within the heater control panel. This is only used to switch the dash fuel gauge from one tank to the other.
---------------------------------------------------------------------------------------------------------------------------
1975/79's use an electric fuel tank selector valve and solenoid assy. This valve is mounted on the left (drivers) side frame rail.
The switch is located within the heater control panel, changes the fuel tanks and the gauges.
New User
Joined: Jul 2015
Posts: 5
Likes: 0
Damaged fuel gauge
I purchased my 72 ford f100 about a year ago and I hadn't realized that we had basically purchased a truck with engine issues. We took it to the mechanic and $2200 later it runs good. When I took it to my mechanic the fuel gauge was working and I was able to fill up the tank. Well now, it always shows that it has half a tank and I've been stranded because it was actually empty. Another issue is, that I use to be able put in $40 worth of gas and now it only lets me put in $13 at a time. So frustrating! I took it back to the mechanic who says the problem is the tank is small. I know for a fact that that is not true. I was able to add a full tank with no problems. He then shut off my second tank permanently so I am not able to use the second tank. He says it was difficult to find a fuel gauge for my truck so he had to fix the old one. The problem is, it still doesn't work. I'm about to take it back to the mechanic because I hate that I have to gas up several times due to the gauge not working. What can be the problem? I mean, if my mechanic can't fix it, what advice do you have for me? It is just so frustrating! Thanks!