[AT] fuel sending unit

Doug Tallman dtallman at accnorwalk.com
Mon Aug 22 09:24:41 PDT 2011


John, in the automotive apps the gauge should go full travel one way 
when the wire is open and full travel the opposite way when the wire is 
grounded. It will usually go somewhere in the middle with a test light 
on the wire. Its a quick test to see if the gauge at least has the 
capability to respond. Doesn't mean its accurate though! Doug T



john hall wrote:
> Doug,
>  I checked to make sure the resistance was varying but failed to see if it 
> quit changing at either end of the stroke. I polished the contacts and tried 
> applying more pressure to the contact with no difference in reading. The 
> sending unit has been replaced at some point but as far as we know the gauge 
> is original. Wonder if the gauge is the problem? At least it registers 
> something with quite a bit of reserve! The tank gets filled only twice a 
> year, when it is time to drill. Otherwise we just keep a minimal amount of 
> fuel in it. I'll pull my service manual and see if it has any resistance 
> values.
>
> John
>
> ----- Original Message ----- 
> From: "Doug Tallman" <dtallman at accnorwalk.com>
> To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
> Sent: Sunday, August 21, 2011 8:57 AM
> Subject: Re: [AT] fuel sending unit
>
>
>   
>> John, all a fuel sending unit is just a variable resistor. Different
>> mfg's use different resistance values for the gauge so you would need to
>> know specs on your particular unit. The sender can be tested with an ohm
>> meter. Sometimes the windings or the point that goes across them are
>> dirty and I have had luck cleaning them. Sometimes the arm looses
>> tension against the windings. Doug T
>>
>>
>>
>>
>>
>>     




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