2006 M35 Gas Tank Capacity

[danmeljeff]

My 2006 M35 Sport manual says the fuel tank capacity is 20.1 gallons. However, the most gallons I've ever been able to put in is ~17 gallons.

Are any of you 06-08 M35 owners able to approach the 20.1 gallon capacity?

[DaleHeller]

I've gotten to nearly 19...

[MagicM]

There's no way you're going to get close to 20.1 gallons unless you run the car until it shutdown from no gas. Even when the yellow gas light comes on there is still a few gallons of fuel left.

[NBP45]

I think the reserve is about 2 gallons....

[StarPD]

My 2006 M35 Sport manual says the fuel tank capacity is 20.1 gallons. However, the most gallons I've ever been able to put in is ~17 gallons.

Are any of you 06-08 M35 owners able to approach the 20.1 gallon capacity?

Regularly running your fuel tank low can cause early failure of the fuel pump in many cases, sometimes subsequently the controller too. Not sure about the M, but definitely on earlier Qs. Fuel pump relies on gas to cool and lubricate it. When the tank is low on fuel, cornering, accellerating and braking cause the little fuel in the tank to surge away from the pickup, making the pump run hot and unlubed. General recommended practice it to never let it get below half tank.

Again, not sure on the M, but on G50 (earlier) Q45s, cost to replace the pump, controller, sensor, and pigtail is usually around $1500. I suspect the M is not too different.

Note that this is not usually restricted to Infinitis. It usually applies to any modern fuel injected car, as they mostly all use an electric in-tank fuel pump, and are subject to the same phenomenon.