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way to test a fuel gauge ?

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bighealeysource

bighealeysource

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Know this sounds pretty lame but purchased a nice,used Smiths fuel gauge for a BN2 and although supposed to work, does not. My existing gauge is a non Smiths unit and works fine so hooked up the Smiths and it does not. Seller swears it did work. Is there some other test other than simply hooking it back up to see if it works ? Know this sounds pretty lame but just double checking. The cost of a rebuilt from the UK is high so trying to avoid that route. Or, does anyone out there have an extra Smiths fuel gauge ????
Thanks,
Mike
 
Is your car positive or negative ground? You may have the wires connected in reverse.

As for testing, if you put it in a circuit with a battery the needle should peg to full, but I'm not sure if that is bad for the gauge. Do you have an extra sending unit? If so, you could set up a test circuit with a battery and check it out with nice new wire. I think you can also do this using a home dimmer switch in place of the sending unit.
 
bighealeysource]

Know this sounds pretty lame but purchased a nice,used Smiths fuel gauge for a BN2 and although supposed to work, does not. My existing gauge is a non Smiths unit and works fine so hooked up the Smiths and it does not.

Seller swears it did work.

Assuming the seller is being truthful, it might be the case that the tank unit and the original gauge are not compatible.

Is there some other test other than simply hooking it back up to see if it works ?

Yes if you can get a Potentiometer and a battery you can apply a voltage over the rang of Zero to Maxim voltage of the battery try a six volt battery they are relatively easy to come by. If the gauge deflects during this test it says it is responsive but not necessarily good..

Know this sounds pretty lame but just double checking. The cost of a rebuilt from the UK is high so trying to avoid that route.

Well you can avoid this cost by sending the gauge to "Nisonger " and ask them to test it for you this cost will be minimal. Consequently:

1] If the gauge is reported GOOD you will need to obtain the correct tank sender unit.

2]If they find the gauge is DEFECTIVE you can then arrange to have them repair it for you.

Nisongner is one of the best OK!!!

Or, does anyone out there have an extra Smiths fuel gauge ????
Thanks,
Mike [/quote]

-----------------------Keoke-- :driving:
 
Hey Bill and Keoke,
Thanks for the feedback. I hadn't even considered the possibility of the
sending unit being incompatible with the Smiths gauge. I "just assumed" it
was a standard sending unit so will check that out. If it's not, could be the
problem. Think I need to do that before I have Nisonger check out the gauge.
Happy New Year,
Mike
 
It has been a while since I worked on my fuel circuit but here is what I remember for a 1967 unit. with key on, if you remove the wire to the sending unit in the trunk, and touch it to frame, meter should go to full (at least that is what I remember). If you lose ground in the sending unit through the tank, the meter will not work. I have never looked at an earlier car so they may be set up differently. These are very simple circuits with a wire wound resistor in the tank and a wiper attached to a float. The wiper position changes the resistance which changes the current through the meter. More current, more deflection. I think the total resistance in the sending unit is about 75 to 80 ohms.
 
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