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Discussion Starter #1
Hey guys, new to the forum here but I have a couple of questions I am hoping can be answered.

I am bench testing all of the gauges (rally gauges) before install.

I have bench tested the temp. gauge, wiring it up to a sender and heating water to a boil (seems to be working correctly)
.what is the resistance range of this sender?
-now the shunt resistor on the temp gauge seems to measure ~56 ohms (i measured it while installed on the gauge)
-the fuel gauge and oil pressure gauge shunt resistor seem to both measure ~35ohm, again measured while installed on gauge.

-does anyone know if these values are accurate?

last question is, is the oil pressure sender a 0-90ohm sender? i plan to use a potentiometer to test the accuracy of these gauges.
 

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Found these readings some time ago, with factory senders;

Fuel: 0 ohms - empty, 45 ohms - 1/2, 90 ohms - full
Oil: 0 Ohms - 0 psi, 44-45 ohms - 1/2 scale, 90-91 ohms - full scale
Temp: 600-700 ohms - cold, 76 ohms - 1/2 scale, 51 ohms - full scale
 

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Discussion Starter #3
Found these readings some time ago, with factory senders;

Fuel: 0 ohms - empty, 45 ohms - 1/2, 90 ohms - full
Oil: 0 Ohms - 0 psi, 44-45 ohms - 1/2 scale, 90-91 ohms - full scale
Temp: 600-700 ohms - cold, 76 ohms - 1/2 scale, 51 ohms - full scale
thanks bud!

what i was lookin for actually was the ohm reading of the shunt resistor on the back of the gauges, so i went ahead and took mine apart to get them.

Oil gauge was 92 ohms
Fuel gauge was 86 ohms
Temperature gauge was 87 ohms

i might replace the original wire wound resistors with new 90 or 86 ohm ceramic ones for reliability.
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81162173_2521513858125090_4838588706883371008_n.jpg
81162173_2521513858125090_4838588706883371008_n.jpg
 

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I've restored these gauges for 30+ years and can't remember ever seeing the wire wound shunt open or bad. I just test them by applying 12V, GND and for sending wire grounded then open to test full swing of gauge both directions. Then put a resistor in line to ground on the sending wire to check for pointer drive to mid position.
 
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