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Gas Gauge Pegged

commuter64

Contributing Member
fuel penta.PNGHi all,


My daughter called to let me know the gas gauge was pegged past empty. I'm familiar with the resistance type sender units with floats that use resistance (ohms). My 69 Camaro uses 0- 90 ohms, for example.

Any tips on where to start looking here?

My boat is Boat engine model is 1992 Per tag: 431B 868529, S/N 4100135494, with DP-C. 1992 Glastron 19'.

Thanks!

 
Last edited:
Thought I'd ask again...Fuel gauge pegged past empty. I see a fuel sensor part # 873772. Wondering how to test it. or, how to test the gauge itself.

Thanks
Tom
 
Shorting the terminals at the sensor should cause gauge to peg full.... check for open wire at gauge first... or poor connections @ gauge next place to look.
 
Happy Spring! Goot my boat out and remembered about the gas gauge. Shorting the leads at sensot pegs gauge past FULL. Have 12volts to gauge and continuity on wires. With sensor leads removed, I measure some resistance across the sensor; not much. Not open either.

Bad sensor? Does anyone know what I should read at sensor? Or, does that depend on how much fuel is in the tank?

Thanks-
Tom
 
Measure ohms between sensor input and ground.... Shorting sensor @ tank and seeing gauge peg proves sensor and +12 part of gauge are OK.... There is a resistor network inside the gauge that allows a sensor that has a range of 40 to 10 ohms ( if memory serves) to appear on the meter as zero to "max". A poor ground @ gauge or poor ground connection to sensor will distort the reading.
 
the gauge determines which sensor/sending unit to use...most everything sold in the US for decades uses the american standard....where 33 ohms between the sensor terminals (S and GND) will provide full scale deflection....and 240 ohms should provide min scale deflections...
 
Finally resolved this. It was the sending unit. Gauge was fine, bench tested it - with an aftermarket sending unit. At empty, resistance was around 240- 250 ohms; full was around 30-33 ohms.
 
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