Gas Guage Malfunction

[Mister.E]

Last night i was driving home and all of the sudden my gas gauge, which was sitting at about 1/4 of a tank, just started to go down rather quickly. it went all the way down past E and i just kept driving because i knew obviously that i had gas. This could definitely prove to be a problem in the long run though if it doesnt start working again. i dont know much about fuel systems but does anyone have an idea of what it could be?

The car is a 1992 180sx, in case that makes any difference.

any info/help is greatly appreciated. :bigok:

[SR20junkie]

what it could be is how were you driving it? fast accel? decel? there is a lever in the fuel pump setup that does monitor the gas level you might want to look at that for beginners, also it could be with the harness itself.

[garagelu]

There really is only two things wrong in your situation. First would be the gauge is broken which might be possible but unlikely. Second is your fuel level sensor in your fuel pump. I am thinking something is wrong there. Replace the sender unit and it should fix it.

[Mister.E]

thanks for the help. i found this diagram and im wondering which part is the fuel sending unit?

is it: [25060] GAUGE ASSY-UNIT,FUEL TANK :confused:

http://www.courtesyparts.com/betasite/240sx-s13-1989-1994/genuine-nissan-parts/fuel-engine-control/172-fuel-tank/-c-1418_1419_1436_1441.html

[Mister.E]

ok well i just got done taking out the fuel pump assembly. i fucked with the floater a bit and it didnt seem stuck. also all of the wires appeared to be in great condition. basically i felt like i accomplished absolutely nothing.

after putting everything back together, though, i cranked the car over and the damn gauge started working again. i dont know what the hell happened or what i did, but hopefully it doesnt happen again. thanks for pointing me in the right direction though.

[Mister.E]

i forgot to mention that i do have one problem after having put everything back together. you guys know the rubber O-ring that seals the fuel pump lid to the gas tank...that shit seemed way too big when i went to put it back on. if i buy a new one will it fit snugly in that groove like its supposed to? i dont want to be leaking pressure and fuel because of a shitty seal. a few people that i have talked to said that their rings were too big too, while others said that their rings fit fine. im not sure what to do at this point. any advice would be cool.

[Drifter Z]

i forgot to mention that i do have one problem after having put everything back together. you guys know the rubber O-ring that seals the fuel pump lid to the gas tank...that shit seemed way too big when i went to put it back on. if i buy a new one will it fit snugly in that groove like its supposed to? i dont want to be leaking pressure and fuel because of a shitty seal. a few people that i have talked to said that their rings were too big too, while others said that their rings fit fine. im not sure what to do at this point. any advice would be cool.

When I removed it, I felt same. It was bit big but you can just try and it will fit right.

[g6civcx]

ok well i just got done taking out the fuel pump assembly. i fucked with the floater a bit and it didnt seem stuck. also all of the wires appeared to be in great condition. basically i felt like i accomplished absolutely nothing.

after putting everything back together, though, i cranked the car over and the damn gauge started working again. i dont know what the hell happened or what i did, but hopefully it doesnt happen again. thanks for pointing me in the right direction though.

What you could have done was measure the fuel level sender resistance with an ohmmeter when you had the fuel pump assembly out of the tank.

As the float travels up and down, the resitance changes and the need on the gauge moves up and down.

I suspect that the sender was binding or you had an intermittent short in the circuit.

As for the gasket, yes you need a new one. A lot of them leak and you will smell fuel inside the cabin. I wasn't able to find that gasket at an auto parts store so you may have to try the dealer or junkyard.

[D1GP]

i forgot to mention that i do have one problem after having put everything back together. you guys know the rubber O-ring that seals the fuel pump lid to the gas tank...that shit seemed way too big when i went to put it back on. if i buy a new one will it fit snugly in that groove like its supposed to? i dont want to be leaking pressure and fuel because of a shitty seal. a few people that i have talked to said that their rings were too big too, while others said that their rings fit fine. im not sure what to do at this point. any advice would be cool.

id go ahead and replace the o-ring, it costs like 5 bucks at the dealership and helps keeps nasty fumes out of your car. as for the gas gauge freaking out, mine did it during the summer. sometimes it would read correctly, othertimes the gauge would get no power. take off the contacts on top of the fuel pump lid and clean em, see if it helps.

[Mister.E]

As for the gasket, yes you need a new one. A lot of them leak and you will smell fuel inside the cabin. I wasn't able to find that gasket at an auto parts store so you may have to try the dealer or junkyard.

damn thanks for all of the info guys, i really appreciate the help. me and my friend are going junkyard hunting tomorrow to see what we can find. if i cant find an o-ring that will work im just gonna get one from the dealer like you guys said.

[ericcastro]

The 3rd posability is the baffle in the fuel tank broke lose. It came loose and occationaly sits against the level and sends bad readings.
seems you solved your prob, but for people using the search button in the future :)