Fuel Gauge

B

Brian54

Member
I recently replaced a badly rusted original gas tank on my 1954 Ford Victoria.The replacement (Bob Drake) is well built and fit perfectly. The issue is the fuel gauge now reads full with the new sending unit and float assembly(only has 6 gallons in the tank).The rod has been cut according to instructions and the unit is grounded to the frame. I must have missed something ; any ideas are appreciated !
 
Is the car still 6v positive ground, or converted to 12v negative ground?
Still using the original gas gauge in the dash?
Is the battery grounded to the engine, and the body is grounded to the engine?

Is the sensor grounded to the tank and frame, or to the body? Grounding to the body often works better. It's a more direct path back to the battery with less connections to potentially be a problem.

Is there a chance you still have the original tank and Sensor?
The new replacement sensors usually have a variable resistor inside. The originals worked on current flow, thru a pair of heat sensitive on/off switch contacts. The original gauge & sensor are almost a matched pair. The new replacement gauge & sensor parts are electrically built more like the '57+ parts.
The electrical specs of the gauges & sensors were changed for '56 when Ford changed to a full 12 volt and again for '57 when they changed to using a dedicated voltage regulator/reducer for the gauges.
If the original '54 sensor from the rusty tank is still functional it has a good chance of being more accurate than the new replacement.

You might be able to get a better/more accurate gauge reading if you add a 10 ohm 10 watt(???) resistor inline from the gauge to the aftermarket sensor.
https://www.ctci.org/battery-for-6v-to-12v-conversion/

https://www.ctci.org/gilsgarage/battery-cables/
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The car has been converted to 12 volt negative ground , the stock gauge had been working well and ,unfortunately, the original sender does not fit in the new tank.
 
The sending unit that came with the new tank is likely incompatible with the old King-Seely fuel guage. You need to get a guage that operates under same principles as the new sending unit.
If the old sending unit worked properly, why not modify mounting holes in new tank to re-use the old sender?
 
Is it possible that the full reading on the gauge has something to do with the fact that the car was originally positive ground ?
 
Brian54 said:
Is it possible that the full reading on the gauge has something to do with the fact that the car was originally positive ground ?
Click to expand...
Polarity won't affect the oem dash gauge (or original sensor). Look closely at the 1st image in reply 2 above.The gauge needle is operated by a heated bi-metal spring, heat isn't polarity sensitive.
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I am still in search of a solution. I even purchased another brand of sender----big mistake as it didn't fit in the hole. Any help would be more than welcome .
 
Brian54 said:
.... the stock gauge had been working well and ,unfortunately, the original sender does not fit in the new tank.
Click to expand...
The best chance of getting a reasonably accurate reading on the original fuel gauge is to use the original sensor.

As Daves55 & paul2748 suggested, can the mounting hardware of either (or both) the tank or sensor be altered or adapted to match each other?

Can you attach photos of the sensor and tank opening? example below...
 

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The original sender/float is identical to the one in the picture ; it and the "new"one will not fit in the Bob Drake tank as the hole is slightly smaller. I have thought about taking the tank out and modifying the hole as a last resort .Thanks for the input.
 
dmsfrr is correct. ("You might be able to get a better/more accurate gauge reading if you add a 10 ohm 10 watt(???) resistor inline from the gauge to the aftermarket sensor.") The original system would have been 10 to 70 ohm including both the sender and the gauge, with the new sender working on 0 to 90 ohms it would not get along with the gauge. I'm chasing down something similar with a '72 Maverick where a full tank (needle beyond full) shows full for about 150 miles and then suddenly crashes. (new sender, old gauge) Happy hunting!
 
Another thought, have you contacted Drake to see if they offer a sender of a different ohm range that might fix your problem? LMC truck, for instance, offers the old and the new senders (ohm rating) as parts for the fuel tank relocation kit on f100 trucks.
 
The new sensor needed a slight adjustment but was worth the effort as it now fits and the gauge works (by my calculation it also appears to be fairly accurate ).The issue was a faulty sensor.Thanks to all that offered help.
 
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