Gas gauge off again on 03 G35

[Road Ruler]

A couple years ago the gas gauge would show 3/4 but the gas tank was actually full. I also had trouble fueling the car as the pump would continually shut off before the tank was full.

It took the dealer 4 attempts to fix the problem. They said it was a shutter sensor issue.

Once again the gauge is showing 3/4 full but in fact the tank is full. As a test I drove the car till the low fuel light came on. I filled the tank and it took only 54L. The tank should take 76L when completely empty.

I am out of warrantee now and want to fix this myself so it gets done right.

I have been working on and building up HP street cars for many years as well as doing my own servicing and repairs.

I know the access to the gas tank is through a service plate under the back seat.

Once I am in there what should I be looking for? Mechanical adjustment of float?? or is there an electronic adjustment somewhere that can be reset or adjusted??

Thanks for any assistance.

[SteveTheTech]

Hey there,

There are a few things that may cause this concern. Depending on the sensor resistance the percieved value to the combination meter may be off. There are two float sensors on either side of the tank, they send signals to the combination meter that are decifered and turned into gauge movement. The ORVR (Onboard Refueling Vapor Recovery) system uses a very small amount of negative air pressure to click the fuel filler off, if there is an issue in this circuit you will have trouble filling it.

If I had to wager a guess without being able to test it I would look toward the combination meter. Check the ESM under DI to find the circuit you will need to test.

[Road Ruler]

Thnxs for your thoughts Steve. Appreciate!

[hwyix]

We used to get these all the time when I worked at the dealer. If you got lucky you replaced just one. Most of time at flaterape warranty time we always recommended replacing both sides.