HELP - Fuel Gauge issues
 

Has anyone had issues with their fuel gauge not working properly ( 2010 370Z)?

My issue, I left work with 1/4 tank of gas which at the time was accurate, by the time i got home 35miles away my fuel gauge said I had 1/2 tank of gas.

When I filled up my tank the following day the gauge displayed a full tank and appears to work correctly until Ii reach 3/4 tank and will stay at the point.

My typical total commute is ~80 miles day.

Has anyone had this issue?
:confused:

I had my fuel gauge sending unit replaced under warranty because all the dots did not light up on the fuel gauge meter after a fill up and the mileage readings were going out of whack. others have had the same or similar problems.

This happened to me not too long ago.....My fuel gauge would ONLY stay at 1/2 a tank unless I filled her up too almost full but as I wasted the fuel it would stay at 1/2 ALWAYS. Long Story short my Fuel Pump/Assembly were defective and had it replaced with a new one via under warranty.

like others have said it's the sending unit on the fuel pump. Replace it under warranty and if you're out of warranty it's that all that hard changing a fuel pump/sending unit out.

Took my dealer 45 minutes to change it out. Can't be that difficult as Falconfixer noted.

Probably the sending unit but I'd check the wiring at the tank to make sure the connector(s) and ground are nice and tight before changing it.

Fuel sending unit replacement fixed it for me.


NOBLE

thank you for all the help guys, i know my next change

I just started having issues... I get in with a 1/4 tank, then within 2-3 miles it's on 1 dot. Then it goes from 50 miles or so til empty to -- within a couple more miles. It has happened twice in 2 weeks. Looks like a trip to the dealer for warranty work.

My '14 does the exact same thing but only in traffic on really hot days. I guess I should take mine in too.

You guys are getting these weird readings when one of the 2 fuel level sending units start to act up. This car has 2 sensors, one on each side of the tank and it takes the measurements from both sensors and averages them together. So if you have one sensor starting to mess up (or possibly the float gets stuck) and it reads empty, but the other one is reading full then you will see a half tank on the dash.

I am actually surprised nissan didnt put a self check DTC to keep this from happening without a check engine light. Even Chevy has it set that if the fuel gauge does not move for a extended period of time it will throw a code and assume its faulty so that the driver does not run out of fuel somewhere and left scratching his head.

the 2 level sensors are wired in a series, yet have different resistance range. go figure.

Really? lol I guess thats probably to put some bias towards one side of the tank, I would assume the passenger one where the fuel pump is. That would explain the tank level dropping on hard right hand turns.

Either way you think it would have a check of some sort to let you know that the fuel level was inaccurate.

My Z threw a service engine soon light and yep it the fuel sensor throwing a code. My fuel gage has been acting up for a time and not very accurate. It flashes with no miles left and there is still 3 gallons of gas in it. Heading to dealer this Saturday and will post up what was done.

I just started having this issue but didn't want to start a whole new thread about it. Filled the car up on Saturday night and have only driven 175 miles since then. When I left for work this morning it showed a little under a half tank of fuel, then the low fuel warning light came on and started flashing that I only had 138 miles of range left (weird). By the time I got to work 22 miles away it showed completely empty, no dots, and no range. I threw 5 gallons of gas in it and no change.

My question is for you guys that have dealt with this issue out of warranty - how expensive of a fix is the fuel sending unit at the dealer? Does that Techron stuff actually clear the issue up or am I pretty much dealing with a replacement item now?

Having any work done at a dealer is going to be expensive. Steep markup on parts and a mechanic's time ain't cheap.

IIRC, the sending unit can be checked with a VOM (see other threads and FSM for details). If it checks out bad, it looks like a fairly easy DIY (at least one DIY thread on this site plus the FSM). If a search for "fuel pump" doesn't work, try "fuel starvation".

I doubt if Techron, et al, will clear up the problem at this point but it's worth a try.

My fuel gauge had been staying around full even after 120 miles but I am switching out the fuel pump when I install the BP kit. Anything else I need to replace if the sensor is bad?

I think youll need to buy the sending unit part. The pump Sasha provides is only a pump. Im assuming Nissan only sells the whole unit, at probably 1000$.

Looks like I have a single turbo Z for sale


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Just had the 1/2 tank symptom when i know there is less in tank.
Is the sending unit a dealer only item, I cannot find it anywhere?
Since I don't believe this is part of drive train I don't think they will replace it under warranty for me.

Cj motorsports
 

Hello all, I have had gas gauge issues as well. My car got stuck at half a tank, but would work fine above half. Anyways, the plastic housing that holds the pump, sending unit resistor, fuel temp sensor etc. was broken in half. :mad: wtf. Nissan is charging me 500$ for a new plastic housing because it comes with a pump, temp sensor, and sending unit. Found a good deal going for roughly 350$ (if im remebering correctly) at Courtesy Nissan. This comes with a pump, temp sen, and fuel sending unit as well. As for me, I will wait for a more quality product to arise. Phunk will be making this product and he hopes to have it done by monday. Seriously guys, if you replace it through nissan it will break again. Get a nicer housing with a billet top and your good to go. :tup:

If it is stuck at full it could be a bad ground as well.

It worked itself out. Thank you though. Now I get 15mpg lol


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ok
 

what ended up being the problem? lol why are you getting 15 mpg?

No idea but it's accurate now
Being tuned safe for boosted applications and 750cc injectors


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The mpg does not work because you have changed your injectors. Mine reads 3 and 4 mpg most of the time.

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When I put in 18 gallons and it is empty after 270 miles...


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Mpg
 

Yeah I thought the mpg didn't change as long as you drove it lightly, but I don't know that for certain. I mean it makes sense, with X amount of air you'll have X amount of fuel. So if your just driving nicely and not under boost I was under the impression mpg would not change.

I think Bullitt said that his guage read like 100 plus mpg and 12k miles till empty. Once you mess with the AFRS and the injectors the ecu is all kinds of confused. I just calculate mpg the old fashion way and because my gas gauge is unreliable I don't drive more than 250 miles before filling up. City only driving is no more than 150 because my right foot has a problem. :eek:

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I'm in boost everyday I drive


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Fuel Sensor Sender Ohm Values?
 

Has anybody installed an aftermarket Fuel Level Gauge? I am interested in doing this to ad to my other after market gauges I have installed but am having trouble finding the Resistance values to my 2011 370Z Sender unit(s) in order to purchase the correct gauge, ie: (? Ohms = Empty) & (? Ohms = Full). Also I am a little unsure since we have two tanks one behind each seat but am guessing their configuration is a Primary Tank and Secondary Tank whereas all readings come from the primary tank as the secondary tank feeds the primary tank by a vacuum line so its function is like a reservoir and the existing digital (The DOTS) fuel level gauge takes the average from both sensors from the primary tank only (I believe)?

I searched the web and looked here for any DIY Fuel Level Gauge installation threads that would help but can't seem to find these answers so any help would be greatly appreciated...

2. Which Sending Unit do I connect the after market Fuel Level Gauge to?
3. Where should I tap into the sensor for the gauge wires?
3. What Resistance (Ohm) values do I use when purchasing the NEW Fuel Level Gauge ie: "? Ohms = EMPTY" and "? Ohms = FULL"?

I own a 2011 370Z with Sports Package (Stick) with the Stillen SuperCharger.

Thank you guys in advance if you can help point me in the right direction. If you want to see the gauges I have installed already have a look at my photo album i there should be some pic in there.

Thank you again for your help.....

My factory gauge works fine just want a different style of gauge so IF I can tap off the PCB behind the Instrument Panel I am ok with that but figured that won't work since the analog data has already been converted to digital so I believe I will need to pull off the sender sensor directly just don't know the resistance values nor where the access point is?

Your idea of our fuel tank is screwed up. We have a saddle tank. Its one tank with a hump in the middle for driveshaft clearance. There is a fuel level sender on each side of the tank. The gauge takes both readings to give you a level reading on the gauge. The person to talk to is phunk. He's the fuel system SME. :tup: Here's a link to my thread on installing phunk's roadrace fuel pump. It has pictures of the inside of the fuel tank.

http://www.the370z.com/track-autocro...p-install.html

Hey Rusty, your "Saddle Tank" description would have been plenty to get my head around it my friend... I did say I was "Unsure" and that I was "guessing" but hey, crack a cold one on me....I do appreciate the link to YOUR other post about the Fuel Pump and the Sponsor
[Phunk's] contact info. I read your entire post and if or when I need to replace the fuel pump I know where to look. I found the information I was asking about and have shared here for others who might be looking. Since there isn't any info (prior to 09/26/17) out there
on what resistance values = EMPTY or FULL that are Factory Sender is using or which sender we need to tap into ie: saddle bag sensor on the Passenger's side or saddle bag sensor on the Drivers's side as both use diffeerent resistance values (see below the OHM's for EACH
Fuel Level SENSOR. Based on the data below believe I have all the information needed to install an After Market Fuel Gauge. Even though i have the OHM's at Emptyt and at Full I am going with a "Programable" Fuel Level Gauge which is like a pot, which allows us to change
the input resistance of the gauge wires to match the Ohms of the sender and get an accurate Empty and Full reading. Hopefully this helps anybody looking to install a Fuel Level Gauge. After I get done wwith my installation I will create a DIY guide to validate the Gauge I
purcchased worked, and that the "MAIN" sensor I tap off of also worked as oppossed to the "SUB Senseor" (which is what [last week me] would have called the sensor on Tank 2).


MAIN (Fuel Level Sensor Unit) (Driver Side Saddle) (Right side of car when facing windshield from front bumper)
Terminals: 2 & 5
Condition: Full = 3 Ohm's (Approx) (Float Height: 229.7mm / 9.04in)
Condition: Empty = 80 Ohms (Approx) (Float Height: 38.5mm / 1.52in)

SUB (Fuel Level Sensor Unit) (Passenger Side Saddle) (Left side of car when facing windshield from front bumper)
Terminals: 1 & 2
Condition: Full = 3 Ohm's (Approx) (Float Height: 32.8mm / 1.29in)
Condition: Empty = 40.9 Ohms (Approx) (Float Height: 241.1mm / 9.49in)



Picture 1 - Shows Locations of both MAIN fuel level sensor and SUB fuel level sensor

http://www.the370z.com/members/370z1...el-sensors.jpg




Picture 2 - Lists Locations of both sensors and other procedures.

http://www.the370z.com/members/370z1...s-main-sub.jpg




Picture 3 - 3D View / exploded view of Tank and connections

http://www.the370z.com/members/370z1...-fuel-tank.jpg




Picture 4 - Lists both Fuel Level Sensors and their Resistances in (Ohms) at conditional states such as Empty and /or Full

http://www.the370z.com/members/370z1...empty-full.jpg





Picture 5 - 3D View / exploded view of Fuel Level Sensor(s), Fuel Filter and Fuel Pump Assembly

http://www.the370z.com/members/370z1...ps-filters.jpg





All information except for the aftermarket gauge was sourced from our 370Z 2011 Service Manual and I have attached the PDF sections relivent to a DIY Fuel Level Gauge installation.


Next Post to follow will be notes on how my install went and the steps I took for a better (play by play) on what to expect, and pictures of the completed Fuel Level Gauge Installation. Once I complete that I will update this post but point
a URL redirect to a DIY new Thread i will start, if somebody doesn't beat me to it?

Thanks in advance for any help you shed on this topic....

I tried uploading the PDF Service Manual called, SECTION MWI AMETER, WARNING LAMP & INDICATOR but it was 1.66MB and the limit is 1.0MB so you will need to get this one yourself, just search on Service Manual.


PS: You MUST BE logged in to the Forum to SEE Inserted Pictures. Attachments can be downloaded by anyone but inserted images can only be seen by logged in users of this forum.

Good job! :tup: You did a chit load of digging for this. Which after market gauge you installing? Gave you some reps too. :D

Hey brother
 

I am looking at a couple am taking screenshots now and will post in a moment and thanks for that Rusty...

What do you think about these, the Autometer is Fully programmable so I know it will work, the others I have to match up the resistance or get out my tackle box of resisters and start doing Series / Parallel crap and Ohm's Law and some beer drinking

http://www.the370z.com/members/370z1...13-1-gauge.jpg


http://www.the370z.com/members/370z1...15-3-gauge.jpg

http://www.the370z.com/members/370z1...14-2-gauge.jpg


If you guys see any matching the resistance values listed above please put a picture up.

Check out SpeedHut gauges. You can customized them. I just a oil pressure, water temp, and diff temp gauges from them. It takes about 4 weeks to get them.

Fuel Level Gauges

Which autometer gauges you are looking at?

I like those SpeedHut gauges, wish I knew about them before I installed my Boost, oil temp, oil press, water temp, voltage, gauges. Also have a 4-in-1 OBDII gauge that does Avg fuel consumption in MPG, RPM's, and some other measurements. I will post pic after I get it installed...

Ok I went with the GlowShift Fuel Level Gauge because a friend of mine has one and he never opened it and is giving it to me. I have attached the PDF Instruction Sheet to give you an idea on how most companies will explain the installation of their gauges. It is programmable meaning it is truly universal for most all cars. Since our MAIN Fuel Level Sensor has an (80 Ohm FULL / 3 Ohm EMPTY) I can use the adjustable resistance dial back of the gauge to set to position number 1 which is 73 Ohm Empty/0 Ohms Full. I spoke to Glowshift and they said it will work perfectly because our sensor will surpass the resistance values of the gauge so the needle should peg out when full and drop to bottom peg when empty. So all of you guys looking to install an after market fuel gauge here are my steps I have taken or will take.

1. Verified in service manual the resistance values of the MAIN sender because that is the one I am going to tap off of. They are 80 Ohms Full/3 Ohms Empty.

2. Searched the web for any Fuel Level Gauge closest o our values. The industry standard closest to our values are 73 Ohms Full / 0 Ohms Empty

3. Pick the gauge you like best and if you need to change the resistance on the gauge be sure it is unplugged ie: no power otherwise you can damage it.

This picture is the glowshift gauge i will be using. As you can see from the directions how to wire it up and how to set the correct resistance value (For us Z owners it is Dial position # 1)

Installation:
1. Remove small floorboard insert behind Drivers seat. (Not the floor persay but the half midway up shelf about the middle of the seats back rest, the shelf behind the seat)
2. Remove temporary insulation underneath floorboard (Shelf piece) NOT the floor where the seat is mounted
3. Attach green wire from gauge to Fuel Level Sending unit top brass nut.
4. All other gauge wires can be tied into fuse box by drivers left ankle IE: Ground, 12V Ignition On, 12V Constant and 12V Headlamp for gauge dimming by 50% at night time. Note any 12V signal can be used for a dimmer just be sure it turns off with the ignition. That does NOT mean connect it to an ignition on 12V line because your gauge would then be dimmed in the daylight hours. You want a line that only becomes 12V live when it is dark out such as your headlight line BUT if too much of a pain simply connect to any 12V line whereas you can switch it on/off and it will automatically lose power when car is off. All my gauges have a central line for their dimmer signal which i have installed a switch in the center console to enable dimming at night time. I only did it this way because I wanted the freedom of not having my gauges not dim automatically everytime i turned on my lights.

Hope this has been helpful and I will post after I get it installed and verify it is working as suspected. I don't feel this will be too difficult. Basically we tap one wire off the fuel sender and run that wire to where ever you decide to install your gauge. The other wires can be tied into fuse box. I don't anticipate the entire job taking more then 2-3 hours IF THAT. But again AFTER i do it i will tell you HONESTLY how long it took me with pictures of any challenges I may encounter that I don't mention here.

Picture of my GlowShift Fuel Level Gauge (7 Color Series) Instruction Sheet. This PDF can be downloaded from:

http://www.glowshift.com/instruction...fuel-level.pdf


http://www.the370z.com/members/370z1...evel-gauge.jpg

Kind Regards,
James (AKA: 370Z1)

Thank You Rusty and Elmo370z for your interests and Likes. I promise after i get it installed to write it uo in DIY format with pictures and step by step guide lines so others may follow if they want to do this Mod. Well earlier i said I was going to install the Glowshift gauge I got from my buddy and still may try it out but I purchased the AutoMeter (see picture below, remember you must be logged into the forum to see it as Inserted Images can only be seen by members who are logged in. Anyway I decided on this gauge with a choice of both RED and BLUE LED which is replaced in the back of the gauge. Oh and this gauge is rated at (73 Ohms @ EMPTY) and (10 Ohms @ FULL) which will work (closely not 100% exactly, but close enough for me, here is what i mean.

Since our sender (Main) is (80 ohms Empty) and (3 Ohms Full)
and the gauge is (73 ohms Empty) and (0 Ohms Full) that means when the sender reaches 73 ohms the gauge will be all the way on empty ie: needle pegged at "E" however since there is 7 ohms to go in reality the car will have a little gas left over, how much i can't say but I will think of it as a nice reserver and besides I will not be disabling the factory dots so that can be my back up to monitor the actual difference between this new gauge claims empty vs an actual empty state. Honestly I don't think it will bother me but if it is too far off I will use some 1/4 watt resisters to match up the resistance of the gauge meaning i will ad a 3 ohm resister in series to make 73 ohms into 76 ohms then in theory it should get close enough. Why only 3 ohm and not 7 ohm you say? because I want the FULL to be dead on so here is why.


Same is true for the Full reading. Our sender says <When FULL>l the resistance will be close to 3 ohms and because my gauge says 0 is Full the needle will not go all the way to the top peg even if there is gas pouring out of the fill hole because the float was never able to rise high enough to reach 0 ohms (Still by how much I can't tell at this point but I suspect it wont be alot. So in theory the 3 ohm resister I added in series earlier changes our gauge to these values (76 Ohms = Empty and 0 Ohms = Full).

In summary if this works as I hope it will then this gauge will accurately display FULL when tank is Full. And the gauge will SHOW Empty SLIGHTLY before TRUE Empty is reached because the gauge gets pegged at E at 76 ohms but we know our float will sink to 80 Ohms (True Empty). So I am ok with having a True FULL state and having a premature Empty but because we are only talking about a 4 ohm difference I can't imaging it being much at all. I anticipate this scenario: I am driving home after work and my AutoMeter Fuel Gauge Hits the bottom peg on Empty and 5-8 minutes later driving city speeds our Factory Dot display goes to One Dot remaining and the orange rectangular Information Center LCD begins to warn you that you only have x amount of miles to go before you run out of gas. So I am ok with that. The reason I can't get both ends of the spectrum to work is because I can only add a single resister to the circuit. IF I really wanted to spend a lot of time to get it perfect, take apart the gauge and simply replace their input resistance circuit to match our sender 80=E/3=Full but I really don't think this is gonna be a bid deal and with the addition of a 3 ohm resister in series it will be close to perfect but still good with out it.

Picture below of the AutoMeter Gauge I purchased:

Link this gauge on Auto Meter's website:
2-1/16" FUEL LEVEL, 73-10

Description of the Gauge:
2-1/16" FUEL LEVEL, (73Ω Emptyl - 10 Ω Full), AIR-CORE, UL
Product # 4315
$59.95 + Free Shipping
Custom Options add Cost
Comes with a RED & GREEN Bulb cover (I think,but double check if you buy)

I purchased a BLUE LED replacement, here is the link to the LED I bought (pack of 10):
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Read more at:
2-1/16" FUEL LEVEL, 73-10

My Purchased Gauge:
http://www.the370z.com/members/370z1...model-4315.jpg


Thanks again...

JT (aka: 370Z1)

I am hoping just using a single gauge off the MAIN saddle side of the tank will be a true reading as I can't see why it wouldn't? As far as I can tell both tanks Fill up and Empty equally But if the fluid isn't equally filled or equally used meaning if both saddle don't use their gas in the same manner then I will need to figure out a way to take an average between them like our Factory gauge does BUT I don't believe this will be an issue.


Please before anyone does this DIY PLEASE let me do it FIRST so I can report back either it was a Success or if I need to go back to the drawing board. I would feel like an AH if it didn't work and some one followed my suggestions. It will work I am pretty sure but we all know of Murphy's Law and it has bit me on more then one occasion....

Talk to you soon

Has the issue always been caused by the fuel baskets sensor? I read for the 2009 MY there was a persistent issue for the fuel basket.