Fuel and Temp gauge issues
Temp:
I warmed the car to about 170 on aftermarket gauge Unhooked and hook the stock gauge up and didn’t move. (Hooked to the aftermarket sender that came with the 12 volt gauge)
I jumped from fuel sender wire 28 ohms to back of temp gauge no movement
Tested out of car using spare fuel sender as you suggested. Put together several AA bats to get 5-6 volts to power gauge and The gauge worked.
could it be the 12 volt gauge sender not compatible with stock gauge
Fuel:
At the main female harness plug it shows 28ohms 29 at sender at tank
Once plugged to pin on cluster it shows 18 at pin and 18 at gauge
All pins tight
Gauge reading 1/4 tank
TEMP
I have no idea what the ohms range of your aftermarket sender is. All OEM senders operate on 80-10 range.
Entire circuit resistance will be different from senders resistance. There is a ground path back through the limiter of complete circuit. Gauge tests only cover 3 different needle positions. I can tell you 1/4 tank should be close to 34 ohms. 29 ohms would be somewhere between 1/4 and 1/2. That 29 ohms would move a temp gauge needle to about the same position of a temp gauge screen. Up into normal range, approx' 190 degrees.
All of this is dependant on what voltage is being supplied. The solid state 7805 regulators with input of 9 volts minimum, 35 volts maximum will put out 4.9 to 5.3 volts, (changes as it heat up), 1.5 amps, and gauges may read just a little bit low. A new mechanical limiter made in Mexico or China,,, I have no idea how much voltage comes out of that or what effect low input voltage will have on its output voltage.
One switched hot wire feeds oil warning lamp, brake warning lamp, and the limiter. Then there should be a noise suppression cap plugged in with the center 12 volt spade of a mechanical limiter. I dont know if those can go bad and wick away voltage.
So... Maybe a OEM correct sender will correct temp gauge operation. I don't know how much fuel you have in the tank or what you expect that gauge to show. Most do have to add a meter match module to these aftermarket fuel senders regardless of what limiter or regulator they use for power supply. hope this helps