My 2000 GMC gas gage keeps bouncing around. Sometimes it says the correct level, then the next thing I know, it reads empty. I can have a full tank of gas but is still reads empty and/or takes its time shpwing full. What can be the problem. A friend told me it might be a relay, but I dont have the money to take it into the shop for a diagnostics test. Please help!
2007-02-16 21:32:25 · 10 answers · asked by cuttur2000 2 in Cars & Transportation ➔ Car Makes ➔ GMC
I own a shop, and have seen this one many times before. How the gauge works is; as the float goes down it moves across the resistor (like a radio volume does), the lower the float goes, the more ground the gauge sees, thus the gauge moves more towards empty. If the gauge itself was bad it wouldn't move at all, and if the float/rheostat was bad it would be all over the place, or not at all. Check the ground wire (going to the float assembly) for bad places in the wire that may be getting ground it doesn't need. Check that where ground attaches to frame, it is getting a good ground, may need cleaning. If you don't find it in the wires, then test gauge by holding ground wire to a clean place on frame, and gauge should go all the way, remove wire, and it should return. If this doesn't fix it, replace the float assembly.
Glad to help out, Good luck!!!
2007-02-17 00:18:25 · answer #1 · answered by Anonymous · 3⤊ 0⤋
Gas Gage
2016-09-28 11:24:41 · answer #2 · answered by ? 4 · 0⤊ 0⤋
Once again I see that nobody understands how a modern vehicle works.
Straight from the horses mouth:
The fuel gauge is an analog device that is located in the instrument cluster. The instrument cluster operates the fuel gauge by the class 2 serial data messages from the VCM/PCM. The fuel gauge indicates the quantity of fuel in the tank when the ignition switch is in the RUN position. When the ignition switch is turned to the OFF, LOCK, START, or ACC position, the pointer may come to rest at any position.
The VCM/PCM measures voltage from a variable resistor inside the fuel tank that is controlled by a float. When the fuel tank is full and the ignition switch is in the RUN position, the resistance is high. The VCM/PCM interprets this signal and sends a message to the instrument cluster indicating the percentage of fuel in the tank over the class 2 serial data line. The fuel gauge indicator then moves to the maximum position or FULL on the gauge face. When the fuel tank is empty, resistance is low. The VCM/PCM interprets this signal and sends a class 2 serial data message to the instrument cluster. The fuel gauge indicator then moves to the minimum position or EMPTY on the gauge face. Failures detected by the PCM/VCM in the fuel gauge signal sends the gauge to EMPTY.
When the system detects a problam, the computer will command the guage to E
Most likely issue is that you have a bad sensor strip in the tank.
If you use poor quality gas, the peroxide in the gas will etch the paint on the sensor strip
The only fix is to replace the sensor strip in the tank
2007-02-18 01:25:08 · answer #3 · answered by Delphi 4 · 1⤊ 3⤋
music has the right answer goin but i had a prob with my truck an it was a plastic insert in the tank that goes around the float and pump. it was welded in with soldier from the factory and the welds broke lettin this plastic box float in the tank. it was hitting the float and holding it at full for a while then it read empty and stayed there. makes me nervous when i saw that floating around all that wiring swimming in gas
2007-02-19 01:35:06 · answer #4 · answered by bearman48064 3 · 0⤊ 1⤋
Your particular gauge is computer controlled via the ECM (Engine computer). The ECM recives a signal from the sending unit in the tank (usually corresponing to 90-270 ohms resistance) If the ECM sees a resistance value outside of this window, It will default the gauge to empty to help alert you to a problem in that system. (it will also store a trouble code without turning on the check engine light) 99% of GM vehicles we see w/ these symptoms turn out to be sending units in the fuel tank.
2007-02-19 09:16:51 · answer #5 · answered by anotherbaldy 1 · 0⤊ 1⤋
Fuel level sensor is your problem,there is a service bulletin that addresses this complaint.seems like the additives that were in some fuel blends was to blame.
2007-02-20 15:17:53 · answer #6 · answered by deltech 4 · 0⤊ 0⤋
replace the gasoline sending unit, this can be a undemanding issue with those vehicles. you would prefer to imagine about replacing the gasoline pump at the same time as the tank is down, then you quite gained't ought to take the tank down again for fairly a at the same time as.
2016-12-04 07:08:10 · answer #7 · answered by gnegy 4 · 0⤊ 0⤋
Bad ground.
2007-02-18 00:40:19 · answer #8 · answered by Anonymous · 1⤊ 0⤋
it could be the float in the tank or ur wires to the gauge r being disconnected and reconnected or ur gauge is going bad good luck:)
2007-02-16 22:15:34 · answer #9 · answered by Dennis R 2 · 0⤊ 3⤋
musicclick good anser go with it
2007-02-17 07:16:18 · answer #10 · answered by Anonymous · 0⤊ 0⤋