Fuel gauge problems
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More Turbo
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Fuel gauge problems
I actually recently got a 1979 ford van. Fuel gauge doesn't work. Shows empty. I grounded fuel sending wire. It shows fuel tank is full. I check resistance through sender unit, 37 ohms. I have 5.3v from the sending unit wire. I moved tank ground from body to sanded part of the frame. What am I missing? I posted here because I seem to get more responce on this part of the forum. Thank you for any ideas.
Fleet Mechanic
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From: Mason City, Iowa
I actually recently got a 1979 ford van. Fuel gauge doesn't work. Shows empty. I grounded fuel sending wire. It shows fuel tank is full. I check resistance through sender unit, 37 ohms. I have 5.3v from the sending unit wire. I moved tank ground from body to sanded part of the frame. What am I missing? I posted here because I seem to get more responce on this part of the forum. Thank you for any ideas.
It sounds like you disconnected the wire at the sender and grounded it, and the gauge needle swept to Full. Correct? Sounds like the gauge and the wiring to it is good.
IIRC, Ford in those days used an IVR as in Instrument Voltage Regulator behind the dash cluster. It kept the gauge cluster voltage supply around 5 volts so with your 5.3 volts at tank end of the gauge wire that sounds good.
So your problem must be in the second part of the circuit. Could be the sender resistance unit itself is bad, or a leaking float that has taken on gas and has drowned itself.
Since you moved your tank ground make sure your frame is grounded well to your battery's neg terminal.
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That was my thought, that the gauge end must be good. I have redone the ground. It now goes to a freshly sanded section of the frame. I have resistance through the sender, so I feel that section is working. I am going out shortly and check the connection between the two.
Fleet Mechanic
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From: Mason City, Iowa
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When you measured the sender connection at the tank and you found the 37 ohms you had the wire running to the gauge disconnected correct? You may have to lift out the fuel pump/sender assembly out look over the sender portion. Also look real closely at the connectors for the power to the fuel pump and sender connectors. Is there anything burnt? That used to be problematic on the pump side anyway. Not that you are chasing a fuel pump problem but, that is a potential issue. New fuel pumps sometimes come with a new pigtail harnes to splice in to use if you have a burnt connector.
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Fleet Mechanic
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Anymore with all the off shore parts, NEW is an acronym for Never Ever Worked, or Not Even Working.
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It doesn't look like the bolts have ever been turned since install. The seller currently had at least 10 vans of this vintage. So I am sure he had changed it on at least one of then. No evidence that this one has ever been apart.
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