gt500bluebyu Posted October 30, 2013 Report Share Posted October 30, 2013 My fuel gauge will start off working fine and then move to dead empty while still in the driveway. any ideas? thanks guys Luke Link to comment Share on other sites More sharing options...
Robert M Posted October 31, 2013 Report Share Posted October 31, 2013 My fuel gauge will start off working fine and then move to dead empty while still in the driveway. any ideas? thanks guys Luke Grounding issue?........................just a guess............... R Link to comment Share on other sites More sharing options...
2010KonaBlueGT Posted October 31, 2013 Report Share Posted October 31, 2013 Grounding issue?........................just a guess............... R The sending unit *IS* a grounding (issue) unit. That's how you test a gauge, by removing the sending unit wire and grounding it. Your gauge should go from full to empty then back again when the wire is ungrounded (or vice versa, I can't remember which). Typically it's a 90 ohm resistance. 45 ohms will show 1/2 tank, etc. You can make a test unit with a rheostat and test the full range of motion from E to F. Test the gauge first (as I directed above). If it works as described, it's the sending unit. That or the gas tank isn't grounded (NOT likely, pretty much impossible)! <lol> Phill Link to comment Share on other sites More sharing options...
gt500bluebyu Posted November 2, 2013 Author Report Share Posted November 2, 2013 Thanks guys I will try the grounding issue same time the cd got jammed in the radio. so anyone know if you can put a factory touch screen in with the shaker 1000 amps and factory subs. my car is a shaker 500 I see the rear pigtail is there but does that matter? and last does any one have a touch they want to see? Thanks so much Luke Link to comment Share on other sites More sharing options...
Macman756 Posted November 5, 2013 Report Share Posted November 5, 2013 You have a base shaker now? The factory NAV can be configured through programming to power the rear subs, but can't switch on/ off like the shaker 1000 can. Link to comment Share on other sites More sharing options...
Robert M Posted November 9, 2013 Report Share Posted November 9, 2013 The sending unit *IS* a grounding (issue) unit. That's how you test a gauge, by removing the sending unit wire and grounding it. Your gauge should go from full to empty then back again when the wire is ungrounded (or vice versa, I can't remember which). Typically it's a 90 ohm resistance. 45 ohms will show 1/2 tank, etc. You can make a test unit with a rheostat and test the full range of motion from E to F. Test the gauge first (as I directed above). If it works as described, it's the sending unit. That or the gas tank isn't grounded (NOT likely, pretty much impossible)! <lol> Phill Phill - How is the ground circuit completed for the sending unit? Is it the tank to the floor? or is it a ground wire in the fuel harness back to a ground location? Below is shown first a 2007-2010 tank........... and then the 2011-up tank.......... Since both tanks are coated and have pads to prevent rubbing and vibration and the bottom of the car is painted, could there be a sure ground without a wire or strap to the under body? Many think these tanks are the same, 2007-2012, or even through 2014.......they are not. R Link to comment Share on other sites More sharing options...
2010KonaBlueGT Posted November 9, 2013 Report Share Posted November 9, 2013 Phill - How is the ground circuit completed for the sending unit? Is it the tank to the floor? or is it a ground wire in the fuel harness back to a ground location? Below is shown first a 2007-2010 tank........... and then the 2011-up tank.......... Since both tanks are coated and have pads to prevent rubbing and vibration and the bottom of the car is painted, could there be a sure ground without a wire or strap to the under body? Many think these tanks are the same, 2007-2012, or even through 2014.......they are not. R Phill - How is the ground circuit completed for the sending unit? Is it the tank to the floor? or is it a ground wire in the fuel harness back to a ground location? Since both tanks are coated and have pads to prevent rubbing and vibration and the bottom of the car is painted, could there be a sure ground without a wire or strap to the under body? Many think these tanks are the same, 2007-2012, or even through 2014.......they are not. R I've never seen a tank with a remote ground and always assumed the tank was grounded through the tank itself or the straps. Now I want to go out and pull my back seat to see if there's a remote ground in the pump/sender harness.... I'm pretty sure there is (remote ground) for the pumps but not sure about the sending unit. But then, if the pumps are grounded via the harness I'd have to assume the sender is too. Then, if the sender ground was a problem the car wouldn't run because the pumps wouldn't be grounded. Anyone have a wiring diagram??? Phill Link to comment Share on other sites More sharing options...
Robert M Posted November 9, 2013 Report Share Posted November 9, 2013 I've never seen a tank with a remote ground and always assumed the tank was grounded through the tank itself or the straps. Now I want to go out and pull my back seat to see if there's a remote ground in the pump/sender harness.... I'm pretty sure there is (remote ground) for the pumps but not sure about the sending unit. But then, if the pumps are grounded via the harness I'd have to assume the sender is too. Then, if the sender ground was a problem the car wouldn't run because the pumps wouldn't be grounded. Anyone have a wiring diagram??? Phill You can't see it in the first 2007-2010 fuel tank picture above because of the picture angle and actually it may be romoved, but it is visible on the 2011-up fuel tank picture..........the bottom of the tank has a protective fiberglass shield. The two tank straps (one on each side) lay across this fiberglass shield at the front end of the tank all the way across to the rear end with no touching/grounding of the tank with the straps. That is why I am wondering if the wire harness that feeds to the sending unit also has a leg that continues back and goes to a ground source? and if that ground source is loose or oxidized then that poor ground could be causing a fuel sender issue.............if it is not the sender itself of course. R Link to comment Share on other sites More sharing options...
2010KonaBlueGT Posted November 9, 2013 Report Share Posted November 9, 2013 You can't see it in the first 2007-2010 fuel tank picture above because of the picture angle and actually it may be romoved, but it is visible on the 2011-up fuel tank picture..........the bottom of the tank has a protective fiberglass shield. The two tank straps (one on each side) lay across this fiberglass shield at the front end of the tank all the way across to the rear end with no touching/grounding of the tank with the straps. That is why I am wondering if the wire harness that feeds to the sending unit also has a leg that continues back and goes to a ground source? and if that ground source is loose or oxidized then that poor ground could be causing a fuel sender issue.............if it is not the sender itself of course. R Generally, when a remote ground is used it's a short pigtail that just goes from the load to a close common ground (engine/chassis) rather than the length of the harness back up to the PCM or Batt. The fuel pumps most likely are grounded with a full length wire because the PCM controls them. I'm not sure if the fuel gauge system is part of the PCM or not though. With a DIC, it's real possible. Phill Link to comment Share on other sites More sharing options...
Robert M Posted November 10, 2013 Report Share Posted November 10, 2013 Generally, when a remote ground is used it's a short pigtail that just goes from the load to a close common ground (engine/chassis) rather than the length of the harness back up to the PCM or Batt. The fuel pumps most likely are grounded with a full length wire because the PCM controls them. I'm not sure if the fuel gauge system is part of the PCM or not though. With a DIC, it's real possible. Phill I was not meaning the ground running forward to the battery or PCM, I meant running a short distance from the top of the tank at the sending unit connection back through that specific harness and attaching to the body somewhere in the back area, over the axle assy.? to the side underbody area next to the tank? etc. R Link to comment Share on other sites More sharing options...
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