gas gauge malfunction?

[knowleqe]

hello everyone,

I filled up today with a little less than a 1/4 tank on my gauge and I ended up only filling the car with 11.42 gallons! The weird thing is that the s14's capacity is 17.2 gallons. That would leave me with 5.78 gallons left in the tank and theoretically 131.2 miles left to go. That doesn't seem right though being that there is less than a 1/4 tank left.

I calculated my mileage and it turned out to be 22.7 mpg. So in theory I could get at least 350 miles easily out of a whole tank. But for some reason my fuel gauge shows only 150 miles right at half and around 220 miles on the last 1/4 marker. Do you think something is wrong with my gauge?

[masticatingcow]

Now, I might be wrong on this, but I think that stock gas gauges read empty faster than the tank actually drains fuel. Whether this is cheap manufacturing or a ploy to keep a driver's attention, I know that in every car I've driven, after filling up, the tank reads full for a very short time, drops quickly to 3/4 and 1/2, and slowly creeps down to 1/4.

My gas gauge has read wrong for at least as long as I've owned the car. When I fill up, it only reads 3/4 full. My solution was to figure out my fuel economy (which is right around 24-25 mpg) and multiply it by the approximate capacity of the full tank. Rounding down for simplicity, 24 mpg * 15 gal tank capacity = 360 miles per tank. That said, I just tank up around 320-350 miles on the tripmeter.

[popogto]

my gauge goes below E and then the light lights on. i think its just bad engineering.

[ricebike]

Now, I might be wrong on this, but I think that stock gas gauges read empty faster than the tank actually drains fuel...a ploy to keep a driver's attention, I know that in every car I've driven, after filling up, the tank reads full for a very short time, drops quickly to 3/4 and 1/2, and slowly creeps down to 1/4.

it's sorta a ploy for this main reason (i think) since gas=coolant for the in-tank fuel pumps & the engineers want u to keep it a certain level in there so the fuel pump won't prematurely burn out during it's warrantied life-span

i noticed this on domestics (chevys/fords/chryslers) as well as other imports (subaru/suzuki/honda/mitsubishi)

[Bryants95240sx]

yea i can run mine like a 1/4 past empty gas light will come on and i put like 16.6 gallons in .

my gass gauge will stay on full forever untill it gets to like half a tank . It just started happening recently though after one day of sliding around it started actin funny.

[evotech240sx]

wow, mines like that too. i have been filling my tank whenever my gas has reached the bottom line for the e, but yet i fill it up to just about 12 gallons........ and i get about 240-250 miles. i might just as well keep driving till my tank gas lights up. (which i hope it that it still works.)

[masticatingcow]

the engineers want u to keep it a certain level in there so the fuel pump won't prematurely burn out during it's warrantied life-span

I hadn't thought of that. Good point.

[illreaxion]

yeah this just happened to me last night too. I thought the gauge was malfunctioning, as I saw my needle go past E a bit...I was like whoaaa...but I noticed that after you fill the car and top it off, it starts to drop quickly after it passes the half mark...nice to know we all have a similar problem and its not just me...otherwise then Id be scared.

[KRUZNBY]

I'm still waiting for my low fuel light to come on. I ran it down to below "E" without the light coming on. I put 15.8 gallons in. I guess I need somewhere between 0-1.4 gal for the light to come on. I feel like Kramer on a test drive.

[ddgsxr504]

The most likely problem is that you have a pin hole in your float on the pump which when you fill the tank it is full of air but after driving around it fills with fuel causing it to sink down more than it should. When I fill my S14 it stays full until about the first 75 to 80 miles then it drops quickly. The gas uage will actually drop to about a 1/4 below the Empty mark before the light comes on. I would most likely suspect that the reason Nissan does this is because of what "ricebike" said about prematurely burning out the pump which if you have priced one aren't too cheap. Actually better AND CHEAPER to go with a walbro even if you don't plan on boosting!

[illreaxion]

I checked alldata today at school, said to check the fuel sending unit, but most likely what you guys have been saying is the culprit.

will switching to a walboro cure this problem?
Modified by illreaxion at 10:24 AM 3/8/2005

[ddgsxr504]

It's not necessarily the pump itself its the sending unit float that tells how much gas is in the tank. They are made of cheap a$$ plastic and over time will eventually wear out.

[illreaxion]

so in other words, replace the sending unit? Im going to call some places tomorrow and get prices.

weird thing...I filled up the other day and I when I opened up the gas cover a LOT of pressure came out...since then the gas has actually been keeping an accurate reading. it tends to drop when you really get on the throttle, but it goes back to what it is. (or should be at least)

[allthrottlenobottle]

my gauge will read just over 3/4 full when its full up to the filler spout. when i changed the fuel pump out about 4 years ago i put a new sending unit in, and it worked fine for awhile but then it started acting up. now when it reads 1/8th of a tank i know i'm somewhere around a quarter or so. anybody swapped out the stock tank for a fuel cell with a walbro pump and maybe an aftermarket sender(ie autometer)?

[illreaxion]

if you used an autometer gauge (or any gauge for that fact of the matter) wouldnt it just tell you if you had pressure in the fuel system, not how much you have in the tank?

[ddgsxr504]

When you close the gas cap it creates a seal and since the fuel system is pressurized it will make a hiss sound when you break the seal to remove the cap. It will usuall be mor noticible when you have an empty tank.!

[illreaxion]

^^

I know that, I was assuming thats what was causing it...just that SINCE then, my readings have been more accurate.

[KRUZNBY]

I drove 447 miles and filled up with 16.3 gallons and still no fuel light. I'm guessing mine does not work.

Is the light supposed to come on when you start the car as a test?

[fatboy]

it's sorta a ploy for this main reason (i think) since gas=coolant for the in-tank fuel pumps & the engineers want u to keep it a certain level in there so the fuel pump won't prematurely burn out during it's warrantied life-span

i noticed this on domestics (chevys/fords/chryslers) as well as other imports (subaru/suzuki/honda/mitsubishi)

bingo