Just purchased an 86na with 80k miles on it last week from a doctor friend of mine. Car is in nice shape and is quite loaded (digital dash, AC, Auto etc). I am wondering about the accuracy of the digital fuel gauge on these cars. Either I'm getting some lousy gas mileage or the scaling on my gauge is off. Also, the manual mentions the fuel remaining gauge should pop "on" when appx 5 gallons is remaining in the tank. On several occasions the fuel gauge has been one bar above empty and the fuel remaing display has not popped on. Ran the self-diagnostic on the entire digital display and everything does work. Any thougths from the experts out there. Other than this and a few missing seat screws the car is great.

Thanks,
Kevin

 

First. To calculate fuel milage, follow these steps. There is no other way. This is the only way that is anywhere near accurate.
1. Fill gas tank to full.
2. Reset trip odometer or note milage.
3. Drive.
4. Fill gas tank to full.
5. Note miles driven.
6. Note gallons taken.
7. Milage is miles driven/gallons taken.

Second. The fuel level sending unit is notorious for going out on the Z31. Some people have luck removing (simple to get to under the rear hatch carpet) and cleaning it, but many find it easier to just replace it. You can read about it in the FAQs and archives on http://z31.com

Third. Your car has a 19 gallon gas tank. Read your owners manual if you don't believe me. You shouldn't even see the 5 show up until around 300+ miles. Typical milage is around 22mpg in the city and 27 on the freeway.

http://zbum.nissanpower.com

 

Thanks for the info....have not yet bothered to do the fill the tank twice test. I did read that the tank was a 19 gallon. With this in mind I decided to purposely fill the car with only 5 gallons to see just how far the fuel gauge would move up. In theory it should jump about 1/4 tank, in my case it jumped up a 1/2 tank which makes me wonder if like you said the sending unit is having a problem.

Again, thanks for your time.