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I have a 260z thats wiring wise all stock. My fuel, clock and tach(sometimes) gauges all work. My voltage is stuck somewhere in negative so I'm not sure if thats electrical issues involving alternator but i don't mind that one not working. My oil and water gauge does not work. I have a newly bought oil sender, the bullet type water temp sender(is this the sender) with single bullet connector connected but the sensor next to it with two wires coming out isn't connected because they were cut completely off.


I took off gauge and put battery + terminal to ign(G) and the black wire to ground. i then grounded my oil wire(Y/B) and it only moves to the 0 position. i thought it was supposed to move all the way? Is the gauge bad?


Any help is appreciated as i really can't afford one right now and don't want to run my car without either of these gauges.


Also how can i tell if my water pump is working? I have no leaks but i feel the engine gets very hot very quickly. I took the radiator cap off and i thought bubbles would come out or you would see the coolant flowing or moving but it was very still. I'm afraid thats also bad.

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The oil and temperature gauge has an internal mechanical voltage regulator. the oil sensor and coolant temperature sensor have a variable resistor connected to ground through the engine. The wires connecting to the sensors complete a circuit through the meter movements.


If both gauges are inoperative, the logical place to look is where the circuits share common components. There should be a +12 volt power lead going into the gauge with voltage present when the ignition switch is in the on position. If you have power there, you most likely have a failed voltage regulator inside the gauge and it should be replaced.


The one caveat to the above is a quirky feature of the oil sensor. The sensor is also designed to be used on cars with idiot light. So at some pressure reading in the 6-10 psi range, the sensor opens the circuit rather than supplying resistance. This is why our oil pressure reading will go left of 0 when we come to a stop after a sustained high speed run. The hot oil is so thin pressure drops below the design limit of the sensor.

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