| This forum is for all years of the Ford Galaxie and all other Full-size Ford, Lincoln, and Mercury cars. This is a place to share information, skills, pictures, and stories for the purpose of building friendships and furthering the enjoyment and restoration of these cars |
Offline
Another electrical question cause I suck at wiring. On my 61, I have been noticing when I fill the gas tank full, the fuel gauge will only read 3/4 full. When I drive the car, the temp gauge will only move slightly past the letter "C". I thought normal position of the pointer would be more in the center of the gauge.
Anyways, the fuel sending unit in the tank was replaced, the temp sending unit on the engine is new and I also replaced the voltage regulator on the back of the speedo/dash unit assembly. I also added a ground wire from the fuel tank to the car frame to ensure a good ground at the tank.
Any thoughts on why the gauges seem to be out of whack?
Offline
the way the system works in the temp sending unit and the fuel sending unit are both variable resisters, and both gauges are actually a voltage gage marked with temp and fuel level rather than volts. The more resistance coming from the sending units the lower the voltage.
The first thing you need check is the gauges. easiest way to do that is to disconnect the wire from the temp sending unit and the fuel sending unit and connect them both directly to ground. Then when you turn the key to the on position the gauge should peg. If it doesn't than either the gages are bad or the voltage going into the gauges isn't correct. To check the voltage take a volt amp meeter measure the voltage on the + side of the gauges. the reading should be 5 volts (assuming the 61 galaxie is the same as other early Ford cars)
If neither of those are the issue than the system is working fine (except for fuel sending unit calibration which I will explain in a minute) The cooling may not be an issue of a bad system, it might be that your cooling system is working well and keeping the car at the temp. As far as the fuel sending unit goes it need to be calibrated when installed. this is done by bending the rod that attaches to the float so that when the tank is full the fuel gauge reads full.
Offline
Thanks Daze for the excellent tutorial! I'm going to keep this one for a winter project. To confirm, when calibrating or bending the arm of the fuel sending unit, I will have to bend the arm upwards so that the float can reach the top of the tank? Just keep bending and checking the gauge to confirm accuracy?
Thread StarterOffline
I would do the first test where you bypass the sending units to ground, now because that eliminates a lot of potential causes of the problem. As far as calibrating the fuel sending unit, actually you will probably need to bend it down. the limiting factor here is the top of the tank and (assuming all the other stuff I said to check seams good) currently the float hits the top of the tank before the sending unit reaches the "full" position. When I did mine I first matched the new sending unit to the old one and then with the fuel tank out of the car and upside down on the bench I was able to do the fine tuning. I ran a ground wire from the tank to the chassis and connected the sending unit to the gauge wire. This allowed me to use gravity to simulate a full tank and make my adjustments accordingly.
Offline
Excellent, thank you!
Thread Starter
1 of 1