Upgrade Gas Meter?

[Great White Versa]

I don't know how many of you have this problem, but my gas meter is HORRIBLE. It seems to do a good job (ie. gives consistent readings) until the meter hits the 1/4 tank mark. From that point on the meter will jump all over. For example. Yesterday I left my house with the tank just barely bellow 1/4, drove the 4 miles to work and the meter showed less than 1/8 and the light came on. I got in the car after work to drive home and as I left the parking garage the meter was at empty, with the light off. A few minutes later it was a little above 1/8 with the light on and by the time I got home it had dipped to well below empty and then back up to one line above empty.

Has anyone else noticed anything similar? This has been happening since I bought the car about a year ago.

How hard would it be to install a more accurate gauge/measurement tool? Would I need a better meter at the tank? A better gauge in the dash?

[Rockhound]

I think it's a common problem for gas gauges to be inaccurate and erratic when the fuel level is low. Every car I've owned has also had the tendency to make the first "half" of the tank last longer than the second - probably due to the shape of the tank. I think by nature these meters are just moderately accurate. Things like parking on a slight incline can have a big impact on the reading as well.

In short, I'd say that your best bet is to get to know your car's average MPG and make sure to always zero out the trip meter on fill-ups. That way, you can always do a little back of the envelope calculation to determine how much fuel is really left.

The dash gauge is not the culprit - it's the measuring technique in the tank. Fuel is measured in the tank via a float...pretty low tech really.

HowStuffWorks has a great write-up on Fuel Gauges and their inaccuracies...http://auto.howstuffworks.com/fuel-gauge.htm

[CodeRed]

If you read the stickies you would have know'n been here.http://www.nissanversa.org/generalfaq.shtml

but yeah, the gas gauge is sometimes off. I have come to find that when my gas light comes on i still have ~3 gallons in my tank.

[Rockhound]

I have come to find that when my gas light comes on i still have ~3 gallons in my tank.

And that is purposeful. If the gas light came on when you really were empty then it wouldn't warn you of anything.

[RetiredTexans]

I did some extensive research on gasoline additives last month trying to determine why my V gas mileage varied so much between brands. I summarized some findings in another thread.

One item I didn't mentioned related to sulphur compounds normally found in gas. Even though it is supposed to be eventually eliminated from gas, the feds have pushed the elimination from diesel fuel harder than gas. I found one reference that stated sulphur deposits form on the fuel level sender on the fuel pump interferring with the readings. Apparently, only the top tier brands still include additives that help remove this coating from the sender. Some manufactures' fuel pumps are more susceptible to sulphur than others per the article, but it didn't name names.

A second item is you shouldn't allow the fuel level to drop much below 1/4 tank indicated. Fuel pumps are designed to be kept cool by being immersed in the gas. The on and off again low fuel light is probably caused by the fuel sloshing around in the tank. My son used to drive his S10 Chevy around on fumes all the time. Naturally it failed and when removed was sortta brown from the excess heat.

[justmerging]

Unfortunately for all of us these problems arise due to the design of the actual tank itself. Because the tank is irregularly shaped the sending unit only sees how high the fuel level is in the tank. It can't actually see how many gallons are in the tank. Usually the tank is larger at the top so the level drops more slowly than at the bottom which is why the lower half of the tank goes so much faster. I hope this cleared it up for everybody.

[sambot]

The first little while I had my V, the light came on at the quarter tank level. Now it comes on anywhere from the quarter tank to the nearly empty level. I try to fill up when it's moving toward the quarter, but on long road trips I don't always see a gas station when the gauge is near, but not at the quarter.

It's annoying, but I figure it's just one of the car's quirks.