Ford Muscle Cars Tech Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
I have a 66 GTA with a very frustrating issue. When I bought it the fuel gauge would read only about 1/2 full with a full tank. I bought a new sending unit-hooked it up outside the tank and the dash gauge worked as it should. Installed the new unit and the false reading still exists. I am on my third sending unit plus I just installed a brand new tank with no soloution. I have checked all the grounds ( firewall to engine, gas tank to frame and sending unit to tank) and when I ground the sending unit wire the dash gauge reads full. I read that the constant voltage unit behind the dash has nothing to do with false readings yet looking at the wiring diagram the circuit passes through it. Could that be my issue?
 

·
Registered
Joined
·
417 Posts
Two possibilities come to mind. The ground to the sender is poor. The float rod is bent or oriented such that the resistance doesn't go to zero.
 

·
Subscriber
Joined
·
661 Posts
if it works as it should outside the tank, then it shouldn't be the constant-voltage unit behind the dash.
check resistance between the tank and battery negative post?
 

·
Registered
Joined
·
1 Posts
if it works as it should outside the tank, then it shouldn't be the constant-voltage unit behind the dash.
check resistance between the tank and battery negative post?
This is what is so perplexing. Three sending units,all new worked fine outside the tank. I hooked up the wire from the gas gauge and ran a direct ground to the tank unit and moved the float manually. The dash gauge would read differently depending on the float position. Install the sending unit in the tank and at best it reads 1/2 full when the tank is full. This winter I put a new gas tank and sending unit in and it does read a bit better but still not the way it should. When I saw the issue was not corrected I ran a jumper wire directly from the battery ground to the sending unit which did nothing. I checked ground continuty betwee the tank, sending unit and frame all good. I checked the ground from the engine to the body and it too is good. I am stumped.
 

·
Registered
Joined
·
417 Posts
It's not an electrical problem then if what you're saying is accurate. The float arm is not moving through its full arc. Either because of its position or the tank is not filling all the way.
 

·
Registered
Joined
·
213 Posts
I’m watching this thread because I have the same issue with my Meteor. With a full tank it shows only a little over 1/2 tank on the dashboard. All connections are clean, and it worked fine outside the tank when it was installed. I’ve just lived with the problem as it’s not a high priority on a car I don’t drive every day, so the tank is topped off almost all the time.
 

·
Registered
Joined
·
42 Posts
I just went through a similar issue with my Meteor. The issue I had was running out of gas in the feeder can (custom part) but when I went to put gas in the main tank (all stock) it would only take a few gallons.

Of course I thought the problem was in the custom portion and messed with that a lot. Ultimately, I traced the problem to the main tank. Here is what I found:

The pickup tube was partially blocked (nothing to do with the gauge). I also held the pickup in the flange and allowed it to rock down until it touched the bottom of the tank. It must have been 3 or 4 inches from hitting the bottom! I had pressurized the tank once when trying to prime the feeder can and must have ballooned the tank out of shape. Who knows if it was even the correct pickup tube over 50 years but anyway, I cleaned the tube and bent it down so it would ride about 3/8" from the bottom of the tank.

So now on to the sender, the float was cracked so i drilled out the end solder plug and drained it. Found the leak and soldered it up (you can buy a new float for like $6 but this was a weekend and i did not want to wait for shipping). Then I bent the rod so that it would allow the float to track the same low point as the pickup tube. The arc of travel for the sender is not adjustable so the FULL reading is just when the float tops out.

I put everything back together and then drove down and filled the tank. Presently showing FULL gauge right now but I am keeping a gas can in my trunk until I find out if the lower end of travel shows EMPTY correctly before I run out of gas!
 

·
Registered
Joined
·
213 Posts
Let us know how it works out!
Hey,is your Meteor a ‘63? Not too many of these around anymore
 

·
Registered
Joined
·
42 Posts
I just can't ride enough to burn that full tank with this COVID-19 going on. I drained out about 10 or 12 gallons today. I screwed in a fitting into the drain bung, attached 1/4 line and let it drain into a couple gas cans until it totally stopped. The gauge is now showing about 1/8th tank. The feeder can still filled when I cranked it up so the pickup tube must still be submerged in fuel.

I filled up a 1.5 gallon gas can and put in the trunk. I should be able to ride that 1/8th tank down to "E" and see what happens - after I figure out my new charging issue.
 

·
Registered
Joined
·
42 Posts
I just can't ride enough to burn that full tank with this COVID-19 going on. I drained out about 10 or 12 gallons today. I screwed in a fitting into the drain bung, attached 1/4 line and let it drain into a couple gas cans until it totally stopped. The gauge is now showing about 1/8th tank. The feeder can still filled when I cranked it up so the pickup tube must still be submerged in fuel.

I filled up a 1.5 gallon gas can and put in the trunk. I should be able to ride that 1/8th tank down to "E" and see what happens - after I figure out my new charging issue.
Update - ran it out of gas today but it was still showing a hair above empty. Need to bend the rod up a little to show empty before the pick up tube sucks air.
 
1 - 12 of 12 Posts
Top