I just rewired my 56 ford and just had one problem with how I hooked up my amp capacitor. It may have damaged the fuel gauge, or not related at all. I decided to replace the VDO gauge even though it worked before the rewire. That didn't fix it so I bought a new sending unit and it still didn't work. The gauge is 240 ohms full, 33 empty and I tested the sender with an ohm meter and it's reading 107. I also pulled it out and in the full position it reads 253 full and 38 empty. I re ground the gauge and I know it has power because I tested it and when the car is on it moves sightly from below the E to just touching it the E. I also tried a new sending wire in case the one I ran to the back of the car was damaged but no difference. So it has power, good ground, and the sender is reading 107 ohms. I also put mu old gauge back in and get the same thing. What else can I test/do? Thanks, Jason
Have you checkt that there is voltage from the hot wire to do sender? If that is ok, then i always take on extra wire and ground the sender lid. Many times the problem is the ground from the sender. Peter
The sending unit in the tank doesn't have a ground wire, I'll give that s try. Thanks guys! Posted using the Full Custom H.A.M.B. App!
Not familiar with that exact car....but all that I've worked on only have power going to one side of the gauge. The other side of the gauge is for the ground wire that goes to the sending unit in the tank. If it doesn't have one, I always add a ground wire from one of the screws that attaches the sending unit to the tank and attach the other end to the body. The fuel gauge grounds through the sending unit and the sending unit has to have a path to ground around the sending unit gasket and anti-squeak stuff on the tank straps. An easy test is to turn the key on and touch the wire that attaches to the sending unit to ground.....the fuel gauge should move all the way past full. If it does you know everything is good from that wire forward and that the problem is the sending unit or the ground path at the tank.
Txturbo, thanks for the advice, I'm going to try that tonight! Posted using the Full Custom H.A.M.B. App!
Do you have a full 12 volts going to the sending unit? Is the wire a heavy enough gauge for the voltage? Yes, I agree with everybody that talked about the grounds. You will figure it out. Let the meter be your friend solving the problem.
Well I ground the sender to the body and then the frame and still no good. Im Reading volts from the sending wire when the car is on, not sure what the true volts read, I was using a monster professional meter my neighbor gave me that has a ton of settings, need to figure it out tonight. I'll keep at it, thanks everyone!
An easy test is to turn the key on and touch the wire that attaches to the sending unit to ground.....the fuel gauge should move all the way past full. If it does you know everything is good from that wire forward and that the problem is the sending unit or the ground path at the tank If this not work, is there a possible that do fuel meter is wired wrong. I dont now what fuelmeter you have? You did write that you ground the fuelmeter ?? The fuel meter should be grounded thru the fuel sender, thats why is very important that the fuelsender have good ground to the body/chassie. Dont give up, you gonna find the problem. Peter
Fodor, what do you mean by the fuel meter should be ground through the sender? That may help as running out of options. Tonight I'll also check to see if the needle goes to full when I ground the send wire. I bought a new vdo gauge and sending unit about a year ago and it worked fine until I rewired the entire car with a universal wiring kit last month. The wires are labeled every 5 inches so I know I didn't cross a wire. I also tried another sender wire as a test in case the wire I routed under the carpet to the trunk was damaged. All 4 gauges are wired together; one + and - for the bulb and another + and - to power the function of the gauge and the other 3 gauges all work fine. I grounded the gauges individually the other night. Like I said before, the meter slightly moves when I turn the car on and I've tested the ohms out of the sending unit. I also tried the old and new vdo gauge, both labeled 240-33 ohms. If you are suggesting I should ground the - on the meter to the sender, I can try that tonight. Thanks for the help! Posted using the Full Custom H.A.M.B. App!
the '56 Ford uses a 12v system and a voltage regulator for the guages.IF the new wiring harnes is for aftermarket guages, it will not have the voltage regulator for the guages. The regulator reduces the 12v down to 5 or 5.5, can't remeber zactly. You need to go buy a cheep $5.00 volt meter and learn to use it if you want to keep an old ford running!
If the car is set up with VDO guages I don't think you'll need the constant voltage regulator,that is for Ford guages. What most of the guys are trying to tell you is that the wire that comes from the guage to the tank,remove it from the tank sender and ground it, turn the key on if your gas guage reads full at this time all is good at this point,then the problem most likely will be with a ground at the tank sending unit, if it doesn't read full then there is a problem with the wire to the guage or voltage,disconnect the sender wire at the guage and use a jump wire to ground that terminal and see if it works.
+ to fuelmeter, from the fuelmeter - (can be markt with S or G in some gauges) to fuel sender bolt/nut. How many terminals do you have back on the fuel gauge and how are they markt. Peter
Thanks guys. It's a new wiring kit and new vdo gauges that were installed about a year ago. I have a late model 302 and alternator with an internal regulator. Tonight I'll try grounding the sending wire. The back of the gauge has "S" (sender), +, and - Posted using the Full Custom H.A.M.B. App!
Ok, I grounded the sending wire and the needle jumped to full! Should have it done that with the ignition switch in off position? I assumed I had to turn it on. So what can I do now to verify if the sending unit works? I thought it was broke and bought a brand new one. So unless I damaged it somehow by doing so many tests and taking it in and out, I don't know what to do now.
Did you ground the guage at the sending unit end of the wire or under the dash,if under the dash try it at the end of the wire at sender,if it works,you could remove sender hook a ground wire to sender and the guage wire and operate the cork lever to see if the guage rises and falls with the movement of the lever.
Try that. Or, with a Ohm meter. Hook Ohm meter one wire to sender, the other wire to ground body/chassie. If you have 1/2 tank gas it should show 100-120 Ohms.
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