Dashboard Lights and Gauges
Fuel Filters
Chevy Silverado

Why would a 99 4Runner fuel gauge read empty when full then flip when the fuel level goes down?


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2005-03-01 19:35:05
2005-03-01 19:35:05

On some vehicles, a sensor connected to a floater, much like the one in your toilet, measures the level of fuel in the tank based on its position. Similar to an electric slot-car track, the resistance of electricity in the lever determines the speed, or in this case, the level of fuel. So, what happens is, the resistance of electricity moves the guage on your dashboard in a near-accurate ratio with the level of gas in your tank. In your case, it appears the wires are connected backwards due to one of three problems - a factory fault, bad grounding in your dashboard, or crossed wires in your guage assembly connectors (check both ends). If your vehicle still has a warranty on it, you might want to take the dealer up on this one and claim you don't understand anything about cars (if you modified any of the vehicle's systems in any way). Else, a fuel pump, wiring correction and testing, and reassembly of your fuel system could cost upward of $600 at some shops. Typical dealer costs range around the $450 area, but an hour of your time, a multimeter, and about a gallon of idled fuel, you can figure this one out on your own. OEM (Original Equipment Manufacturer) fuel pumps costs anywhere from $69 to $200 depending on your vehicle, application, and equipment arrangement because some fuel pumps are actually inside the gas tank! This is something anyone would need to know first; prior to disassembling a fuel system and wasting a cartoon-filled Saturday morning! Josh Sugar Land, TX


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I would assume that the wires are hooked up backwards

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It would be better to write: My gas gauge reads empty. Note that 'gauge' is singular, so it needs the singular verb, reads. If you had several cars all with gas gauges that read empty, then the verb would be read.

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Fuel level sender (in tank) faulty. If replacement doesn't correct fault, check sender wiring back to instrument for poor connection. Finally, replace gauge.

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Because the gas in being forced to one side of the tank and the sensor that reads the fuel level is reading a lower level as gas gets sloshed around.

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On a car, there is a float inside your gas tank. It is attached to a switch that sends the empty.....full signals to your fuel gauge.

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