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Question about a P0463 on 2001 silverado 1500

posted Apr 15, 2016 17:25:01 by Richard Livingston
Hi Paul I love your videos I got your book on my laptop I join your prem. channel but it expired and I didn't take full advantage of it that year I had it. I go back when I have time. But you and Eric are the best.
Ok my Question is I watch your video about the P0463, and did somewhat what you did I got to go back and jump the sensor wire with the connector plug in. I believe its the sending unit or a bad connection at the sending unit. I know its not the gauge because
I hook it up to my scanner and was able to control the gauge with the scanner so that tells me the gauge is working and the PCM has control. also my scanner on the data screen shows a 5 volt reading so I disconnected the plug wire at the sensor I took a reading at the sensor wire it read 5 volts then I took a reading at the ground wire and that was good but when I shorted the two wires together at the sensor unplugged I thought I would see 0 volts or near zero on my scanner but it only drop to 4.5 volts I also thought the fuel gauge would go to full but it didn't move. I need to go back and do the same test with the sensor plug in. Now I move on to something else and was checking for misfire on the truck and after I started the truck after a few seconds the fuel gauge went to full like it was shorting out then when back to empty. I check the scanner again it still reads 5 volts. I can still move the fuel gauge with the scanner. so what's your thoughts ???
Another question is the fuel sensor in the tank is solder to the variable resistor and this is in gasoline and not sealed how come it doesn't short out the circuit ?
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4 replies
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cheryl hartkorn said Apr 16, 2016 14:58:48
what size engine? dual sending units? you could unplug it and put a potentiometer in terminals a and d on the connector. and change the resistance then if the wiring is good the gauge should move. the fuel level sender is nothing more than a variable resistor anyway
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cheryl hartkorn said Apr 16, 2016 14:58:49
what size engine? dual sending units? you could unplug it and put a potentiometer in terminals a and d on the connector. and change the resistance then if the wiring is good the gauge should move. the fuel level sender is nothing more than a variable resistor anyway
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Tyler said Apr 17, 2016 16:27:39
Hey Richard! Just to be clear, are you doing your testing at the four-pin connector at the fuel pump assembly?

also my scanner on the data screen shows a 5 volt reading so I disconnected the plug wire at the sensor I took a reading at the sensor wire it read 5 volts then I took a reading at the ground wire and that was good but when I shorted the two wires together at the sensor unplugged I thought I would see 0 volts or near zero on my scanner but it only drop to 4.5 volts I also thought the fuel gauge would go to full but it didn't move.


Good move doing this test. I think you're right, the indicated voltage should have gone down to zero, but clearly didn't. If you're positive that you're getting a good connection between the two fuel level sender wires, then it looks like you've got high resistance in the sensor ground wire.

Cheryl's recommendation of installing your own potentiometer in place of the sending unit would work perfectly. You could also use a jumper wire to provide a different ground to the sensor signal wire. If the scan data now shows zero volts, then you're looking for a wiring problem.
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Inge_Jeppesen said Apr 21, 2016 19:19:53
Gasoline does not conduct current. That is why it's not shorted out.
Norway
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