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1950 Gas Guage Sender

Started by Joe G CLC 12138, January 04, 2006, 11:51:36 PM

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Joe G CLC 12138

Ive got a 1950 Series 62. With ignition off, gas guage reads empty.With ignition on or running, guage reads full. It never reads anything in between. So, guage movement appears to operate. I pulled sender out of the tank, expecting to find it burned out as the shop manual suggests. Well, the float is definitly bad, it has some liquid inside which would cause it to sink better than float, which should cause an empty reading rather than a full reading. But an ohmeter reads 1.5 ohms on what should be the empty position, and 35.5 ohms on what should be the full position, with gradual changes in between. Has anybody ever checked one of these? Are these numbers in the ballpark?

JIM CLC # 15000

01-04-06
Joe G., from what you have discribed, it sounds like the wire from the gauge to the sending-unit is grounding-out and should be replaced. As for the sending unit, I think it will be ok once you get the fuel (gas) out and the float resealed.
Good Luck, Jim

Bill Ingler CLC7799

Hi Joe- Since you have the sending unit pulled from the tank, this is a good time to check the sending unit for proper ground. Connect a jumper wire from the sending unit connection post to the end of the wire going to the fuel gage. With another jumper wire ground the sending unit to a clean spot on your frame. Manually position the float arm to empty. Turn on the ignition and see if you read empty on the gage and if yes then manually postion the sending unit arm to differnt positions and check gage to see if the gage follows the arm positions. If the gage follows the arm postions then your problem is a bad ground between sending unit and tank. I suspect this could be your problem.

Doug Houston

Your resistance readings look good. A little rule on fuel guages is: low tank: low resistance, and high tank: high resistance.

Since the dash unit pins to full scale, there is an open circuit between the float unit and the dash gage. Other posts have the right advice. Either its bad wiring between the float unit and the dash, or a bad ground, which is already suggested.

A quick test is to have the ignition turned on, and touch the tank unit contact to ground. The gage should go to zero. If not, its in the wiring.....or possibly, the gage could have an open coil in it. The test then, would be to ground the terminal at the gage to see if it goes to zero. If not, its the gage.


Joe G. 12138

Thanks for the help, fellas!!! Problem solved (or at least figured out). There were two wiring problems. The first was a poor splice on the wire that goes to the sender terminal. Evidently the previous owner replaced the last 6 inches of wire at some time, and the connection went bad. The other problem was poor ground continuity  between the body of the sender and the tank itself. (It was previously jumpered between the tank and chassis...that was OK ). It seemed like a lot of permatex or sealer was on the screw threads.
      At the lowest position of the float swing, Im reading a little less than 1/8 tank....good enough for now. Top of swing reads Full.
      Next Ive got to locate a replacment float. A couple of parts houses are ordering up some for me to take a look at next week when they come in....their catalogs didnt list dimensions. Ive seen aftermarket plastic replacments in the past, but I cant remember where (now that I could use one!)
     Again, thanks for the help!!!!!