5 volt or 6 volt dash regulator for my 67 fish car.

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cudajim

cudajim

cudajim
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I decided to check my gauges while I have the instrument cluster on the bench and I found I'm getting no output from the built-in regulator on the 3-terminal fuel gauge used in the 67 Barracuda. Since I have several hundred 7805 and a few 7806 regulators in stock I decided to give it a try and it works well (on the bench). My question is should I be using a 5 volt regulator or 6 volt? Some of the other threads seem to imply I should be using the 6 volt regulator because the gauges are designed with that in mind.

I know I could buy a better regulator from RTE but it wouldn't be free.
 
Well, neither the 5V or the 6V regulator are what the gauges were designed for. The stock regulator gives you a 12V PWM pulse of about 45% duty cycle. I'd say go with the 7805 and don't worry about it. Stock gauges are notoriously inaccurate anyways.
 
Well I had nothing better to do so I decided to build up a little board with a LM317 variable regulator and a pot to adjust it on the fly. I'll hook it up tonight and figure out what output voltage seems right.
 
After screwing around with the variable voltage regulator I have concluded that it needs 5.0 volts so I went back to the plain old 7805 regulator and called it done. I did have a bad temperature sensor and a bad oil pressure sensor. I replaced them both and everything now works correctly.
 
I honestly don't think those archaic gauges "know" the difference.
 
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