Fuel gauge problems?
#1
Fuel gauge problems?
Is anybody else having a fuel gauge problem? My '08 LaCrosse gauge goes nuts when I get drive about 200 miles starting with a full tank. It can do anything from telling me I'm completely empty to simply being grossly inaccurate. A friend's wife has an '04 Buick (forget the model) which has a broken fuel gauge. There's a guy in town currently trying to sell an '08 Lucerne in " Really good condition inside and out except gas gauge doesn't work." I Google for "Buick fuel gauge problems and found out that GM cars in general have a problem because the MoCo got a bad supplier of "stepper motors", whatever they are. If you've been having a problem with your fuel gauge, what was the cause and how did you fix it? TIA.
#2
Good question, good start. Can't vouch for '08's but fuel gauges used to be a rheostat or potentiometer. This was grounded in the fuel tank and as the resistance varied would change reading of the gauge. May of coarse be going from analog to digital with newer cars but the principal would be similiar.
Sounds like the ground may be intermittent at the tank sender unit, may have access to it through trunk bottom (or not). Don't know what stepper motor is either, hopefully more answers to follow.
https://en.m.wikipedia.org/wiki/Stepper_motor Here it is, I'd call it a servo motor though. Never had need to know about or ever troubleshoot.... Until now maybe lol.
https://en.m.wikipedia.org/wiki/Servomotor So if no one knows, make up your own answer I guess.
Sounds like the ground may be intermittent at the tank sender unit, may have access to it through trunk bottom (or not). Don't know what stepper motor is either, hopefully more answers to follow.
https://en.m.wikipedia.org/wiki/Stepper_motor Here it is, I'd call it a servo motor though. Never had need to know about or ever troubleshoot.... Until now maybe lol.
https://en.m.wikipedia.org/wiki/Servomotor So if no one knows, make up your own answer I guess.
Last edited by Rich B.; 10-12-2018 at 11:46 AM.
#3
https://www.ebay.com/sch/i.html?_nkw...+stepper+motor Learning curve here, suppose these correspond with digital display, more accurate. Don't really notice any gauge flutter these days lol.
#4
https://www.ebay.com/sch/i.html?_nkw...+stepper+motor Learning curve here, suppose these correspond with digital display, more accurate. Don't really notice any gauge flutter these days lol.
#5
Good question, good start. Can't vouch for '08's but fuel gauges used to be a rheostat or potentiometer. This was grounded in the fuel tank and as the resistance varied would change reading of the gauge. May of coarse be going from analog to digital with newer cars but the principal would be similiar.
Sounds like the ground may be intermittent at the tank sender unit, may have access to it through trunk bottom (or not). Don't know what stepper motor is either, hopefully more answers to follow.
https://en.m.wikipedia.org/wiki/Stepper_motor Here it is, I'd call it a servo motor though. Never had need to know about or ever troubleshoot.... Until now maybe lol.
https://en.m.wikipedia.org/wiki/Servomotor So if no one knows, make up your own answer I guess.
Sounds like the ground may be intermittent at the tank sender unit, may have access to it through trunk bottom (or not). Don't know what stepper motor is either, hopefully more answers to follow.
https://en.m.wikipedia.org/wiki/Stepper_motor Here it is, I'd call it a servo motor though. Never had need to know about or ever troubleshoot.... Until now maybe lol.
https://en.m.wikipedia.org/wiki/Servomotor So if no one knows, make up your own answer I guess.
#6
I could be way off base here, but a motor is just that , a motor. Before going off the deep end it might be a good idea to confirm the sending unit in the tank is operating correctly.. Once you know what you are dealing with , you can go from there.
Stepper motors are used to control HVAC and idle speed/ air control functions. They are controlled some electrically and others electronically.
I would still start with the sending unit and all the connections to and from it.
Even the latest "Fuel Modules" still use a float to provide the signal regarding how high or low the level is in the tank.
I would not be concerned with the PCM shutting down your engine due to the lack of fuel. If it quits it's because you are out of fuel or the fuel pump circuit has died and there is no fuel pressure.
Stepper motors are used to control HVAC and idle speed/ air control functions. They are controlled some electrically and others electronically.
I would still start with the sending unit and all the connections to and from it.
Even the latest "Fuel Modules" still use a float to provide the signal regarding how high or low the level is in the tank.
I would not be concerned with the PCM shutting down your engine due to the lack of fuel. If it quits it's because you are out of fuel or the fuel pump circuit has died and there is no fuel pressure.
Last edited by hanky; 10-14-2018 at 07:31 PM.
#7
I could be way off base here, but a motor is just that , a motor. Before going off the deep end it might be a good idea to confirm the sending unit in the tank is operating correctly.. Once you know what you are dealing with , you can go from there.
Stepper motors are used to control HVAC and idle speed/ air control functions. They are controlled some electrically and others electronically.
I would still start with the sending unit and all the connections to and from it.
Even the latest "Fuel Modules" still use a float to provide the signal regarding how high or low the level is in the tank.
I would not be concerned with the PCM shutting down your engine due to the lack of fuel. If it quits it's because you are out of fuel or the fuel pump circuit has died and there is no fuel pressure.
Stepper motors are used to control HVAC and idle speed/ air control functions. They are controlled some electrically and others electronically.
I would still start with the sending unit and all the connections to and from it.
Even the latest "Fuel Modules" still use a float to provide the signal regarding how high or low the level is in the tank.
I would not be concerned with the PCM shutting down your engine due to the lack of fuel. If it quits it's because you are out of fuel or the fuel pump circuit has died and there is no fuel pressure.
Thanks for the info about the PCM and when it would shut down the engine. I guess if it would shut down the engine based on the fuel gauge reading, that would have resulted in a massive recall.
Thanks for replying!
#8
I don't blame you for trying to determine the easiest to correct possible cause, let's face it , the less we need to do the better.
Unfortunately , not all similar problems have the same solution. What I have suggested is based on years of experience learned, some from GM Factory Service Training and some from the school of hard knocks.
The better way to tackle a problem like this is to start at the source and work your way to the gauge itself. Even if it means to get access to the sending unit and verify it is working correctly , it doesn't make much sense to start in the middle and hope you went in the right direction.
Unfortunately , not all similar problems have the same solution. What I have suggested is based on years of experience learned, some from GM Factory Service Training and some from the school of hard knocks.
The better way to tackle a problem like this is to start at the source and work your way to the gauge itself. Even if it means to get access to the sending unit and verify it is working correctly , it doesn't make much sense to start in the middle and hope you went in the right direction.
#9
I don't blame you for trying to determine the easiest to correct possible cause, let's face it , the less we need to do the better.
Unfortunately , not all similar problems have the same solution. What I have suggested is based on years of experience learned, some from GM Factory Service Training and some from the school of hard knocks.
The better way to tackle a problem like this is to start at the source and work your way to the gauge itself. Even if it means to get access to the sending unit and verify it is working correctly , it doesn't make much sense to start in the middle and hope you went in the right direction.
Unfortunately , not all similar problems have the same solution. What I have suggested is based on years of experience learned, some from GM Factory Service Training and some from the school of hard knocks.
The better way to tackle a problem like this is to start at the source and work your way to the gauge itself. Even if it means to get access to the sending unit and verify it is working correctly , it doesn't make much sense to start in the middle and hope you went in the right direction.
#10
Roger that JB on the Boomer SS SIlent Service, Jr. was on a few also (son). The one I recall was the Rhode Island and a few others. Doesn't talk about it much, I don't ask. He was a cook and made E8 recruiting his last few years (retired). Beat me out, I was only a E7 and retired Army(R). Also served in Navy on destroyers in the early 60's, was an ETR. I started Navy and ended Army, he started Army and ended Navy, hmm.
And thank you for your service also.
And thank you for your service also.