Fuelgauge

Tiny
DAVIDEDDIE
  • MEMBER
  • 2000 PONTIAC GRAND PRIX
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
2000grandprix 3.1 changed fuel pump pumpworks butguage gos to full then drops to empty how much voltage gos to sender
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Wednesday, July 6th, 2011 AT 11:46 PM

9 Replies

Tiny
FACTORYJACK
  • EXPERT
I can not find literary confirmation, but I would suspect that since the PCM provides the voltage and the ground it is probably 5 volts. I will attach the schematic.
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Thursday, July 7th, 2011 AT 4:54 AM
Tiny
DAVIDEDDIE
  • MEMBER
I checked voltage ihave 6 volts how do I check the ground
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Thursday, July 7th, 2011 AT 6:59 PM
Tiny
FACTORYJACK
  • EXPERT
The circuit is grounded through the PCM, about all you can do for the circuit is check wire continuity. The fuel tank pressure sensor and the A/C pressure switch also are grounded through the same circuits. I would suspect you would have other issues, along with the gauge fault, if you had a ground concern. If you just replaced the fuel pump, and not the complete fuel pump module, I would suspect maybe a faulty sensor. If you replaced the complete fuel pump module with sensor, I would suspect that there may be a problem with the install like a stuck float or interference with hose/wiring.
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Thursday, July 7th, 2011 AT 10:17 PM
Tiny
DAVIDEDDIE
  • MEMBER
I removed the pump twice ichanged thepump and sensor ifailc to mention I had problems with ignition switch had another key and everything was fine when iturn key tostart guage gos to full then inafew minutes it gos to empty and lite comes on
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Thursday, July 7th, 2011 AT 11:53 PM
Tiny
FACTORYJACK
  • EXPERT
Was this a pump module that you had to install a provided connector, to allow connection to the new pump module? Open circuit would indicate an empty tank. Referencing the schematic, you could measure the resistance or the sender and circuit from C200, or C405. C200 is at the right of the instrument panel, looks like it may be behind the kickplate, or under the dash. It is a 56 pin connector, with a bolt making the connection secure. C405 is in the rear compartment, forward of the spare tire well. If you get an open circuit reading, you will have to trace it toward the sender. Is this the same function of the gauge, as before you made a repair, or did the malfunction occur after you replaced the pump? Another check that will check the function of the gauge, short pins A and D at the sender connector with a jumper. Like open circuit being empty, short circuit should be full. Turn the key on, and see what the gauge does.
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Friday, July 8th, 2011 AT 2:27 AM
Tiny
DAVIDEDDIE
  • MEMBER
Tried jumper needle gos to empty when turn key on
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Friday, July 8th, 2011 AT 7:33 PM
Tiny
FACTORYJACK
  • EXPERT
You shorted the PPL wire pin A, to the blk/wht wire pin D? I would think that it would go to full, but anything is possible. The fact of the matter is that it behaved different, correct? Then if you open the same circuits and turn the key on, does it read full?
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Saturday, July 9th, 2011 AT 5:09 AM
Tiny
DAVIDEDDIE
  • MEMBER
Yes then it sowly gos to emptyand fuel lite comes on
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Saturday, July 9th, 2011 AT 9:34 PM
Tiny
FACTORYJACK
  • EXPERT
My next step, if it were in my stall, would be to view the PCM data on a scan tool, specifically the fuel level sensor, and see if it corresponds. If the fuel level input to the PCM doesn't change, then there may be a fault with the cluster. If it functioned the same before you replaced the pump, and the sender, the fault may not lie in that area. You stated you had ignition switch problems, but it sounds like it was just lock cylinder or key issues, and not the electrical portion, which I would not suspect would cause you a problem that would relate solely to the fuel gauge.
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Sunday, July 10th, 2011 AT 4:39 PM

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