Fuel Gauge 1968 Traveller
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Researchingreg
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Fuel Gauge 1968 Traveller
My 1968 Travellers fuel gauge when the petrol tank is full, shows just over half full. Can the gauge be adjusted to show the correct reading?
Re: Fuel Gauge 1968 Traveller
No. Fault could be with the gauge, the sender or the voltage regulator (a small one behind the speedo, not the dynamo control box in the engine bay).
Start by looking in the boot area. Remove the spare wheel and look for where a single green/black wire is attached to the sender in the middle of the tank. Remove the wire from the sender. With the ignition ON, the gauge should read empty. Now short the wire to a good earth point (use an extra piece of wire if necessary). The gauge should now read full. Switch ignition OFF after testing and replace the wire. Report back on the results, and we can advise whether the replace the sender or conduct more tests.
Start by looking in the boot area. Remove the spare wheel and look for where a single green/black wire is attached to the sender in the middle of the tank. Remove the wire from the sender. With the ignition ON, the gauge should read empty. Now short the wire to a good earth point (use an extra piece of wire if necessary). The gauge should now read full. Switch ignition OFF after testing and replace the wire. Report back on the results, and we can advise whether the replace the sender or conduct more tests.
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Researchingreg
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Re: Fuel Gauge 1968 Traveller
Thanks I will try that as I now have filled the tank to full.
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Researchingreg
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Re: Fuel Gauge 1968 Traveller
Thanks for the info. I have tried the method you suggested by shorting to an earth point. However I may not have connected to earth properly. It did not work the guage is still showing just over half full as before. and when I shorted it the gauge did not move to full so I probably did it wrong.
Re: Fuel Gauge 1968 Traveller
Could you just confirm that with the lead disconnected, the gauge read empty? If yes, then we are moving closer to an answer.
By way of explanation, a 12 volt supply goes to a voltage stabiliser behind the speedometer. A regulated supply then goes to the fuel gauge and then to the sender in the tank and thus to earth to complete the circuit. The sender is a variable resistor with a float arm. when the tank is full there is low resistance, effectively a direct connection to earth, and the gauge reads full. As the level drops, the resistance increases and as less power flows, the gauge reads lower. (This is a simplified description ignoring things like which way the electrons are moving.)
When you shorted the wire to earth, you were simulating a full tank. As the gauge did not read full, it shows that the sender does not appear to be at fault - it might still be faulty, but if so, then it is definitely not the only fault.
Do you have a volt meter or multimeter? If yes, then we can check the stabiliser that way, otherwise we can try a couple of other things. If you have a spare speedo, then it would be easy to swap the stabiliser and/or gauge.
By way of explanation, a 12 volt supply goes to a voltage stabiliser behind the speedometer. A regulated supply then goes to the fuel gauge and then to the sender in the tank and thus to earth to complete the circuit. The sender is a variable resistor with a float arm. when the tank is full there is low resistance, effectively a direct connection to earth, and the gauge reads full. As the level drops, the resistance increases and as less power flows, the gauge reads lower. (This is a simplified description ignoring things like which way the electrons are moving.)
When you shorted the wire to earth, you were simulating a full tank. As the gauge did not read full, it shows that the sender does not appear to be at fault - it might still be faulty, but if so, then it is definitely not the only fault.
Do you have a volt meter or multimeter? If yes, then we can check the stabiliser that way, otherwise we can try a couple of other things. If you have a spare speedo, then it would be easy to swap the stabiliser and/or gauge.