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TR4/4A Voltage Stabalizer and Fuel Gauge Readings


Darth Vader
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I installed a TR4A voltmeter in my TR3 when I converted to an alternator. I put a new voltage stabilizer in line in front of the fuel gauge to lower the voltage to 10 volts as required. The gauge works but the dial will only read a little before the half way mark when the tank is full? Is this an issue with the stabilizer or does the tank sending unit float arm need to be bent? The sending unit float is centralized and not hitting the sides.


Obi Wan
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Is it a modern replacement stabilizer or an original-type stabilizer? If it's a modern one, the problem is almost certainly in the fuel gauge. If it's the older type, it could be either.

The modern stabilizers give you a constant 10V. The original ones turned on and off periodically, with the expectation that the average output voltage would be more or less sorta like maybe approximately 10V, maybe. The gauges were so slow to respond that it didn't matter much. But if the stabilizer failed, pretty much anything could happen.

The most common failure mode for the modern ones is that the input fuses to the output, so you get whatever the system voltage is, 12-14V; occasionally, when totally zapped, the output is zero. So, you'll get either a high reading on the gauge or nothing.


Karl, I have three background questions.
1) Why did you decide to install a new voltage stabilizer?
2) When did the fuel gauge last read correctly for you?
3) Assuming the temperature gauge is electric, how is it reading? Is it also reading low?
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