2003 Infiniti G35 Gas Gauge indicates Empty, No Accelration

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PKOSCHY
Posts: 1
Joined: Mon Aug 02, 2021 5:18 am
Car: 2003 Infiniti G35

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After a year without cleaning, I finally found time to wash, and wax my 2003 Infiniti G35 Sedan. I spent the day detailing my vehicle, and afterwards time to drive the newly minted car out of my garage. After starting the car, the “Service Engine Soon” light illuminated with the gas gauge indicating empty. I had filled the vehicle the evening before. I pondered what I could have done while applying wax to the car. Did I get water somewhere where it should not have been, but how? Did I have a hole in my gas tank?

Incidentally, about two weeks earlier, I noticed that the fuel tank door would no longer lock. I would spray lubricant on the door actuator pin and that seemed to help for a bit. Unfortunately, that issue was intermittent. Actuators are expensive, and thankfully I hadn’t purchased yet.

So, I am now sitting with this immaculate clean vehicle, with a full tank of gas indicating empty that won’t accelerate past, maybe 3-miles per hour. I spent time on the computer researching and just didn’t think it was the fuel sensor or sending unit. Thinking something became wet, I thought I would wait for everything to thoroughly dry.

My wife arrived back home and started research of her own, and was adamant it was a fuel sending unit. Late in the day, I decided to investigate. I snapped the rear seat out of the back of the car which was easier than I anticipated. Two retaining pins, pull forward and gently raise up the seat. The passenger side of the vehicle is where the fuel pump is located. I removed the top of the container, positioned with four screw tabs. The first thing I noticed was two broken wires from the fuel sending unit within the wire harness. I touched the wires together, as my wife watched the fuel gauge. The gauge indicated properly, and the vehicle power revved-up. I spliced the wire together. I also found another wire frayed and fixed that, which happened to be for the fuel door actuator. Now, everything works as advertised, fuel indicates properly, and car accelerates normally. I did not have much luck clearing the Service Engine Soon light with the accelerator dance so I borrowed a code reader and cleared the fault. I contributed to that by accidentally starting the car with the fuel sending sensor detached. That indicates a high voltage sensing code. Oh, and the car won’t start either.

I want to thank my wife for encouraging me to look into the fuel sending unit. I was expecting to have the car towed to Infiniti and pay a premium for the diagnostic and repair. Why the wire was frayed or broken remains a mystery. No indication of any rodents. I now think it’s due to the poor roadways in California, with the constant vibration.

For those with fuel gauge issues, gently pull back the sheathing on the wire harness under the back seat. You may notice a broken or frayed wire which is an easy and inexpensive repair.

By the way, I just had the car smogged the day before!
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VStar650CL
Technical Expert
Posts: 8288
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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PKOSCHY wrote:
Mon Aug 02, 2021 7:24 am
For those with fuel gauge issues, gently pull back the sheathing on the wire harness under the back seat. You may notice a broken or frayed wire which is an easy and inexpensive repair.
Nice work (and kudos to the wife as well)!

One other thing to look out for with Nissan/Infiniti fuel pumps is a blackened ground pin at the pump connector. When pumps start to go bad they often still function but draw lots of startup current, which gradually heats and deteriorates the ground pins. Since the sender usually shares the ground with the pump motor, it's a crapshoot which symptom will show up first, wrong sender indications or fuel starvation.


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