# gas gauge problem



## nissanbri (Sep 2, 2005)

on a nissan 1987 turbo the gas gauge works for about 5 gallons then it drops to empty. What is going on.

Thanks for advice.


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## ICP Sux0rZ! (Jan 10, 2005)

your fuel level sensor (the thing in the tank) is probably dirty


you have two options

1. take it out and clean it off

2. buy a new one


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## dales86t (Nov 1, 2005)

as above ^^^^


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## nissandrew (Aug 23, 2005)

^ I third that


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## ICP Sux0rZ! (Jan 10, 2005)

if u choose option two

Sensor For Analog Gauges 

Sensor For Digi Gauges 

either of those will require some manipulation to get into the tank (the arms dont like to go in easy, just requires some patience and some wiggling)

if u decide to clean it, take your out (it looks like a metal cylinder and dismantle it, i would find some way of marking how the float goes on cuz it does matter) once apart take a cleaner (not sure what type as i replaced mine) and clean off the metal contact leads, then reassemble

BEFORE you drop it back in have someone start the car and slide the float up and down the sensor to check for proper function


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## lostmenoggin (Sep 10, 2005)

Will that fix the secondary gas gauge? My gas light and the 2nd gas gauge don't work.


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## ICP Sux0rZ! (Jan 10, 2005)

lostmenoggin said:


> Will that fix the secondary gas gauge? My gas light and the 2nd gas gauge don't work.


prolly unless ur actual guage is broken


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## AZ-ZBum (Nov 21, 2004)

lostmenoggin said:


> Will that fix the secondary gas gauge? My gas light and the 2nd gas gauge don't work.


More than likely, they do. It's doubtful you've ever gotten low enough to see them. What's the most gallons you've ever put in?


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## lostmenoggin (Sep 10, 2005)

About 17.. I've driven around with the main gauge WAY past E for about 40 miles or so numerous times to see if it would kick on. The gas light and the secondary gauge have never kicked in.


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## AZ-ZBum (Nov 21, 2004)

lostmenoggin said:


> About 17.. I've driven around with the main gauge WAY past E for about 40 miles or so numerous times to see if it would kick on. The gas light and the secondary gauge have never kicked in.


Weird. You're one of the few that appears to have this problem.


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## nissanbri (Sep 2, 2005)

how do you remove the gas gadge screw it out or pull.


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## '85 fairlady (May 1, 2004)

I have pulled the fuel level sensor out and mine looks nothing like that... I also have the same problem, I'll get to about a quater of a tank left of gas and the the gauge will just stop reading untill more fuel is put in and also if the gas gets too low the arnig lamp and the car doesn't say anything, I forget what it's called.


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## ICP Sux0rZ! (Jan 10, 2005)

it doesn't look like what?


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## nissanbri (Sep 2, 2005)

its a metal cylender in side is a strip of metal with a slider that floats and reads your gas level. on top of the metal cylender is a tab with 4 wires soderd on it red black green and i think yellow.


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## ICP Sux0rZ! (Jan 10, 2005)

mine doesn't look like that one...........oh wait a i got anew one.. :thumbup:


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## AZ-ZBum (Nov 21, 2004)

nissanbri said:


> how do you remove the gas gadge screw it out or pull.


The gas gauge is not the problem. It's the fuel level sending unit.


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## ICP Sux0rZ! (Jan 10, 2005)

AZ-ZBum said:


> The gas gauge is not the problem. It's the fuel level sending unit.


im pretty sure hes refering to the sending unit, i had a lil trouble trying to figure out how to get it out the first time i did


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## Zen31ZR (Mar 24, 2004)

I've removed entirely too many fuel tanks, to do pumps and sending units, and in 3 feet of snow too........ It's a huge PITA, especially when the tank is much over 1/4 full.


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> I've removed entirely too many fuel tanks, to do pumps and sending units, and in 3 feet of snow too........ It's a huge PITA, especially when the tank is much over 1/4 full.


swapped mine out on a full tank :thumbup: i was scared i was gonna blow my self up


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## MaxQ (Jun 3, 2004)

same here, swapped mine out in about 20 minutes....took more time to wiggle the new one back in than it did to unhook and remove the old unit. Piece of cake.


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## tim1950 (Nov 8, 2005)

I'm having the same problem. After about 50-60 miles, the guage registers empty. I can watch the miles till empty indicater fluxuate. I use the trip meter and fill up at 250 to 275 miles. The liters of fuel left numbers (canadian model) comes on at about 19 liters, with around 175 miles on the odometer. Now that youv'e told me how to change/clean the fuel sending unit, I won't have to guess anymore.


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## Vertigo1 (Dec 19, 2004)

*yes*

note the TWO floats on the sending unit. One drives the main guage, the other drives the 1/4 tank guage. Honestly, I'm not sure which activates the idiot light, but one of them does! I had no prolems getting the new unit into my tank when I did it a couple years ago, stick the floats in, then drop the rest right in, bolt it up, plug it in, and know how much fuel you have!


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## ICP Sux0rZ! (Jan 10, 2005)

i replaced mine a couple months back, but i think i need to take it out and drop the tank and do a good deep clean of it, my gauges is a couple gallons off now so theres some shit in my tank getting the electrodes dirty fast


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## lostmenoggin (Sep 10, 2005)

i hate repetetive posts...


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## AZ-ZBum (Nov 21, 2004)

I hate repetative posts...















hahahaha... couldn't help myself.


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## Blackjack (Oct 13, 2014)

I've got a similar problem, and I appreciate those who posted to this thread, as it gives me a little hope my sending unit could just need cleaning. I need some additional advice before I start to dig into this.
Newly purchased 85' 300zx....previous owner said he'd recently had the fuel tank flushed and the entire fuel system gone through.
My particular problem is that the %itchin Betty voice alerts every time the fuel gauge cycles low, and apparently I have a loose wire, somewhere causing that to happen when I hit a bump in the road. Bump..."fuel level low"....bump "fuel level low....accompanied by the gauge cycling to zero and then back. It doesn't always cycle back to the same reading....so I'm guessing it's the sending unit. Either dirty terminals, wires crossed, bad ground.

I've pulled up the carpet and the metal cover to find what I _think _is the sending unit access , because it has the various colored wires attached to connectors around the bottom half of the 5 inch inspection circle.
It also seems that the "maintenance" done by the previous owner, may be the culprit, because one of the screws was missing, allowing fuel smell to waft into the aft compartment....

I'm _supposing _I'm looking at the sending unit cap....(not sure) with all the colored wires....but then is the fuel pump somewhere else or is that accessible through the same hole?

Does anyone have photo's of what I should expect to see once I pull that cover off?
I'd like to try to clean, and perhaps assure a better ground that may have a bad connection myself, if I can. It's possible the previous owner hooked the wires up wrong. Do I need to drop the tank to access the sending unit? (The fuel pump seems to work as expected).

Any advice would be appreciated.


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## smj999smj (Jan 1, 2006)

IIRC, there are two access panels in the "trunk" area: one for the fuel pump and the other for the fuel sending unit. I forget which one is which as it's been a long time since I worked on one. You might be helped by a part diagram; try looking it up at NissanPartsZone.com or CourtesyParts.com.


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## Blackjack (Oct 13, 2014)

smj999smj,
Thanks for the quick feedback. I was able to view the part on that link.
If my Vin matches up correctly, it appears from that diagram, that the fuel pump is separate from the sending unit, and that it is one cylindrical sending unit(not the kind with a separate wire and float).
I was hoping I could find out a little more about troubleshooting the wires and oems here. (What each wire provides).
I suppose i could shell out the 100+ bucksand just swap out the sending unit, but if that's not the problem, (perhaps it's a lose ground wire elsewhere), I'll have a spare sending unit I have no use for.
Sometimes you have to do what you have to do.
Thanks


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## smj999smj (Jan 1, 2006)

Yes, it is cylindrical. It's actually two fuel sending units in one; you have the main sending unit for the main tank reading, and then there is a separate sending unit for the lower part of the fuel gauge that reads the 1/4 tank fuel level in increments, if you have that style gauge. Your best bet is to get a copy of the Nissan Service Manual for your vehicle. Due to the age, I'm not sure how available downloadable versions are, but it's worth checking around, maybe a google-search, check the knowledge base at NissanHelp.com or Nico's website. Personally, I'm a bit old school, and prefer the paper version. You may be able to find a used one on Ebay for around $35. They are worth every penny! It'll provide you with wiring diagrams and symptoms charts, torque specs and repair procedures better than any other manual available. You could also purchase a single vehicle subscription from ALLDATA which can much of the same information. Autozone.com has free repair guides which often have wiring diagrams, but can be a little lacking for some information. Sending units are pretty basic. Voltage goes through the gauge to the sending unit. The sending unit acts as a variable resistor based on where the armature is floating in the tank, and then the circuit continues to a chassis ground. Basically, you need to get a wiring diagram and figure out the power wires coming from the gauge(s) at the sending unit. If you unplug the harness connectors form the sending unit, ground those particular wires, the gauge needle should go to the "FULL" position on the gauge. If it does, this will tell you the gauge and the circuit to the sending unit is good. You'll want to make sure your ground wires have good continuity to ground at the harness connectors. If those are good, you can do a resistance test on the fuel sender itself using an ohmmeter, but you'll need to remove the sender from the tank and have the service manual specs as to what resistance should be at the listed levels of the float.


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## Blackjack (Oct 13, 2014)

smj999smj,
Copy All!
All good stuff....That's exactly what I'm going to do.
Hopefully I'll find a poor ground somewhere...but the good troubleshooting isolating steps you suggest, give me at least a framework to go by.
I'll be watching ebay for a service manual. I think our local "pick a part" might also be a good alternative for putting my hands on a sending unit, providing the 300zx's they have are a similar unit.
I know I'll need to purchase another "O-ring" regardless, if I'm going to pull that sender.
Just wanted to say thanks for taking time to offer your suggestions.
Blackjack


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