QX56 gas tank/fuel gauge

I drive mine until I get the 3 bars flashing and I usually end up putting 22 gallons in at that point. Now if I fill up when the fuel light comes on I only get about 20 gallons in the QX. But it's not a big deal to me because my Lexus GS350 does the same thing. When DTE gets to 0 I still only get between 15.5 and 16 gallons when the tank holds 18.7...seem like all vehicles are similar...or they are tired of us pushing the fuel to the limit.

The fuel cools and lubricates the fuel pump so running it very low isn't good for the fuel pump anyway.
 
QX56 Fuel gauge explained

I know this thread is a little old, but I want to shed some light on this issue. I was also curious as to what was going on with the fuel gauge not registering the remaining 6 gallons are so of gas that is left in the tank when the gauge is on empty. I decided to open up the tank to see what was going on. what I found out was something that I have suspected. The problem is twofold, first it is how the tank is design and second it is how the fuel gauge arm level is design. The tank is long with an upward design, so when the fuel gets low the gas in the tank is spread out at the bottom. This is where the second problem exist, Infiniti for some reason design the fuel gauge not register the remaining 6 gallons that is spread out at the bottom of the tank. I think this is by pure design. I also found out that the pump sits in a container that is full of gas, so when the gas is low in the tank, the fuel pump is still always submerge in gas. So with this, I don't think you can do any damage to your pump by running the tank low. After looking at the tank I kind of understand why they did this. I included some pictures for reference. I will say this, if some one is brave enough, it looks like you can bend the arm a little to get more of accurate read on the gauge (I do not recommend it, but it looks like it is possible). I hope this shed some light on this subject.
https://www.dropbox.com/s/yz1qwci9guny0nb/IMG_0271[1].jpg?dl=0
https://www.dropbox.com/s/9j6u4gq76or9idm/IMG_0272[1].JPG?dl=0
https://www.dropbox.com/s/3orfc6rj21y6ma9/IMG_0273[1].JPG?dl=0
https://www.dropbox.com/s/wo7udqkutiwpk61/IMG_0275[1].JPG?dl=0
 
didn't know this was a secret/unclear... :)

nissan designed things this way on purpose. the car is a V8 5.6L so it doesn't take a lot of effort to empty a tank and certainly does not take a long time to burn through a few gallons, so they designed the tank conservatively.

the petrol pump uses the petrol to keep it cool and lubricated, so yes that too is by design.
 
marctronixx said:
didn't know this was a secret/unclear... :)

nissan designed things this way on purpose. the car is a V8 5.6L so it doesn't take a lot of effort to empty a tank and certainly does not take a long time to burn through a few gallons, so they designed the tank conservatively.

the petrol pump uses the petrol to keep it cool and lubricated, so yes that too is by design.
Click to expand...

I didn't know the reason, so I appreciate the info. It doesn't make sense to me since my previous Lexus LX470 had a more accurate fuel gauge and it was a v8. My e92 M3 also had a v8 and didn't have the issue either.
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