# Fuel Gauge Malfunction??



## b14sleeper (Dec 31, 2004)

alrite, i need to know how to fix this, my b14 fuel gauge is malfunctioning...whenever i fill it up, it only goes till about three quarters. also, i think that the gas mileage on the car is really bad, i think it happened after i installed my coffe can muffler... so how do i fix it. i have searched all 417 threads related to this, and still no help, so please do not tell me to search, i wish i could tell you how many mile per gallon i get, but my odometer doesnt work(that sux)


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## B14_Stealth (Aug 14, 2003)

did you try tapping the gauge to see if it starts working? My temp gauge does that sometimes. Hmm i donno about just having a muffler... i know that after i installed the CAI then i got shitty gas mileage because i dont have a full exhoust so its sucking air..but the fumes ain't going anywhere.


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## '98200SXse (May 1, 2003)

B14_Stealth said:


> did you try tapping the gauge to see if it starts working? My temp gauge does that sometimes. Hmm i donno about just having a muffler... i know that after i installed the CAI then i got shitty gas mileage because i dont have a full exhoust so its sucking air..but the fumes ain't going anywhere.



Well I know my mileage has went down here lately, since my Check engine light has been coming on / going off. I normally shift around 4-5K (5 speed), and I am hard on it sometimes w/ high speed full pedal to the metal, but I've been getting around 29 mpg, and it seems to be slowly dropping. I know my check engine light is on due to some of my emissions system not functioning correctly, Im also due for a tune up (77,000 miles). I also have 2.25 inch exhaust w/ magnaflow muffler so thats not helping, but when I first got the car I was getting nearly 38-40 mpg before I put on the exhaust/intake/ 17's rev wheels ; ( . Now I can't seem to get 30 mpg out of it, and my parents v-6 Buick century (4 door family car) gets more than I do !!


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## IanH (Feb 11, 2003)

[QUOTE='98200SXse]Well I know my mileage has went down here lately, since my Check engine light has been coming on / going off. I normally shift around 4-5K (5 speed), and I am hard on it sometimes w/ high speed full pedal to the metal, but I've been getting around 29 mpg, and it seems to be slowly dropping. I know my check engine light is on due to some of my emissions system not functioning correctly, Im also due for a tune up (77,000 miles). I also have 2.25 inch exhaust w/ magnaflow muffler so thats not helping, but when I first got the car I was getting nearly 38-40 mpg before I put on the exhaust/intake/ 17's rev wheels ; ( . Now I can't seem to get 30 mpg out of it, and my parents v-6 Buick century (4 door family car) gets more than I do !![/QUOTE]
I had the same problem when I upgraded my wheels......
Drive faster harder with mods plus the drag from the bigger wheels and tread.
I get 25 mpg with 5 sp around Dallas and 28 - 32 on the freeway at 80 ish.


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## Nostrodomas (Jun 15, 2002)

[QUOTE='98200SXse]Well I know my mileage has went down here lately, since my Check engine light has been coming on / going off. I normally shift around 4-5K (5 speed), and I am hard on it sometimes w/ high speed full pedal to the metal, but I've been getting around 29 mpg, and it seems to be slowly dropping. I know my check engine light is on due to some of my emissions system not functioning correctly, Im also due for a tune up (77,000 miles). I also have 2.25 inch exhaust w/ magnaflow muffler so thats not helping, but when I first got the car I was getting nearly 38-40 mpg before I put on the exhaust/intake/ 17's rev wheels ; ( . Now I can't seem to get 30 mpg out of it, and my parents v-6 Buick century (4 door family car) gets more than I do !![/QUOTE]
Why dont you check the code. Look at the top of the b14 section and there is a sticky on how to do it. Then you will know what is wrong with your car, and maybe causing your bad gas milage. 
Im guessing that its your o2 sensor. A tune up will help your milage out also.


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## Nostrodomas (Jun 15, 2002)

Oh and to answer stelths question, Its probably your sending unit going bad. Either that or you have a short in one of the wires comming from under the rear seat, where the fule pump/sending unit are, to the dash.


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## b14sleeper (Dec 31, 2004)

hey nos...what about me?


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## IanH (Feb 11, 2003)

b14sleeper said:


> hey nos...what about me?


Fuel gauge is relatively simple. Assuming the voltage is correct at the cluster i.e. other gauges are fine, you only have the sender in the tank and the gauge head. 
There is normally a way to check the gauge head in the cluster by shorting and opening the sender unit. On other cars when you do this the needle lines up with little white marks on gauge face. I don't know if Nissan is the same, cant find it in the FSM Factory Service Manual, see sticky at top of B14 section. 

See FSM page 91 in EL section to test resistance of the sender. Measure the resistance, should be full at 36 ohms and empty at 129 Ohms. 

So if you put this target resistance in place of the sender the gauge head will read full at 36 ohms and empty at 129 Ohms. 

A Final comment, if your odometer and fuel gauge are both bad it may be time you looked for a replacement cluster. Got mine with matching milage on odometer for $50.

Hope this helps, good luck........


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## IanH (Feb 11, 2003)

IanH said:


> Fuel gauge is relatively simple. Assuming the voltage is correct at the cluster i.e. other gauges are fine, you only have the sender in the tank and the gauge head.
> There is normally a way to check the gauge head in the cluster by shorting and opening the sender unit. On other cars when you do this the needle lines up with little white marks on gauge face. I don't know if Nissan is the same, cant find it in the FSM Factory Service Manual, see sticky at top of B14 section.
> 
> See FSM page 91 in EL section to test resistance of the sender. Measure the resistance, should be full at 36 ohms and empty at 129 Ohms.
> ...


No little white lines on my Nissan gauges....


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## '98200SXse (May 1, 2003)

Nostrodomas said:


> Why dont you check the code. Look at the top of the b14 section and there is a sticky on how to do it. Then you will know what is wrong with your car, and maybe causing your bad gas milage.
> Im guessing that its your o2 sensor. A tune up will help your milage out also.



I actually have checked the codes, got P0440, P1448. Which im assuming is my gas tank cap starting to leak, along w/ a problem w/ my charcoal canister at the front my engine. Something along those lines is what i've aquired by SEARCHING THE FORUMS under those code #'s. If anyone has had this problem and wants to chime in, and help a brother out, then feel free to do so.I really don't know where to start on the P1448 code, should I just replace the charcoal canister? Is there a way to clean it out?? thanks in advance!!


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