Faulty gauge

2005 INFINITI G35
128,989 MILES
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CAR4ME
  • MEMBER
  • 7 POSTS
I do not know that it is bad. The mechanic put two sending units on and still jumps around. it would never go below half tank so I was wondering if the ground wire was dirty or something. He told me to fill it up and it would start to work. I do nt know . What do you think?
Dec 13, 2016 at 7:10 AM
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STEVE W.
  • ✓Experienced Mechanic
  • 15,368 POSTS
Various items could cause a fuel gauge to jump around. Sending unit could be faulty, it is nothing more than a variable resistor with a floating lever and making poor contact. If it has had 2two new ones and still does the same I would hook a scan tool onto the vehicle and run the gauge test on the tool. It allows you to alter the lever from empty to full in steps. If the gauge responds correctly then it is either a bad sender or bad wiring. If however the gauge reads half tank while the tool is sending it a full signal, you either have a bad circuit in the dash or a bad stepper motor in the gauge.
Dec 13, 2016 at 11:58 AM
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