Fuel gauge not reaching Full mark? 2004 G35X

[btexpress]

Wifes' car, recently the fuel gauge will not reach full, even when filling tank until nozzle clicks off. Takes about the same amount of fuel as before this occurred, however she is worried about running out if the gauge is faulty.

I am going to test the sender when I get a chance, not sure if it can be purchased separately. Or could this issue be related to one I read about the shutter valve on the end of the fill pipe?

Thanks for any input. I am an indy tech so I have the knowledge and tools to pursue this, looking for any common occurrences with fuel gauge.

[qship96]

Try aome Redline SI-1 or similar fuel system cleaner first- could be a sticky float mechanism in tank.

[Q45tech]

If tank hasn't been operned to replalce fuel pump, the usual problem is chemical contamination of the variable resistance material in level sensor.Dealers should be familiar with local variances due to the number they repair.

It often takes years before the public and independents learn specifics.

We have a Master Tech at Infiniti and Lexus who keeps us up to date on problem and fixes.

But on vehicles newer than 6 years we always recommend trips to dealers for resolution.

[SteveTheTech]

There is a bulletin (either ITB05-031, or ITB08-041) that references this issue depending on the symptoms and applicable vin range.

The ORVR inside the fuel tank operates on very small amounts of negative pressure and if it is deemed that your fuel tank is not full (either by the amount of fuel you put in visible amount in the tank) after refueling is attempted, there is an updated internal tank shutter valve that helps resolve this.

If you are out of warranty this is not a job I would recommend doing yourself. This procedure requires your to stick your arm elbow deep into a razor sharp tank of caustic liquid. The first time anyone I have seen do this attempts this repair they end up bleeding and frustrated.

However; the part is really cheap.

[btexpress]

Thanks Steve, I was skeptical of that valve only because it took 5 years for this problem to occurr. Having been an auto tech for 35 years, I am too familiar with bleeding and wounds as part of the job.

When I can get the car away from my wife, I intend to pursue replacing that valve, and testing the fuel sender. Worked at Ford for 20 years, and expect this sorta thing on them; this Infiniti has been very trouble free and only regualr maintenance required. This fuel gauge issue has been the only concern to come up, except for issues with the original Goodyear tires. Nice car!

[fixer]

your g35 has 2 sending units in the fuel tank, the driver side is easily replaceable, the pass side is buit on the fuel pump. but there is a separate seniding unit available that can be replaced easily enough. i hav a lot of problems with these sending units. if you attempt to replace the shutter valve, it is on the far side of fuel tank and there is a razor sharp baffle in the way. it can be pushed up to get your arm under it but when you want your arm back it will pin your wrist at the bottom of the tank. be very careful because that is where your main artery is in your wrist. there is not enough room to put both hands in the tank to push the baffle once you get it stuck. i have had luck by placing a cover over the sharp edge of the baffle before pushing my hand through. you are right it is easy to replace but getting to it can be a problem if you want your hand back.

[SteveTheTech]

It's such an sh*t job and there is nothing like experiencing the inside of a half full tank and razor sharp baffles. Makes you love the job doesn't it?

Putting a slit piece of rubber hose over the bottom is a good idea, I reach in there and use my fingers to roll the edges under (it's very thin aluminum) only like 1/2 to 1" using a blind guess and the move it forward (depending on your arm size and flexibility). Once your arm is in there and you have access to the end of the filler nozzle it's a simple quarter turn.