HELP - Fuel Gauge issues

370z1

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?

Rusty

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. Here's a link to my thread on installing phunk's roadrace fuel pump. It has pictures of the inside of the fuel tank.

phunk's road race fuel pump install

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370z1

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






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






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






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







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







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.

Attached Files

Fuel System.pdf (494.4 KB, 81 views)

Rusty

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

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370z1

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









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

Rusty

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?

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浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html

370z1

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...

370z1

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




Kind Regards,
James (AKA: 370Z1)

Attached Files

GS-715_fuel-level.pdf (214.2 KB, 11 views)

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:



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

dedoom

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.

Z's

My 09 had the basket fall off into the tank as well. Not very uncommon from what I've read over the years. It happens on other Nissan models as far as I'm aware. All the symptoms everyone had sounded like a broken pump housing to me.

1slow370

you know a lot of the time you can pull out the sending units and on the arm is a little sweeping contact that rubs against a potentiometer strip on the sensor cleaning that with some alcohol can fix it if it is just covered in deposits. if its worn through its bad. also sometimes you can bend the little contact to put more pressure on the strip. saves replacing $x00 sending units

see here

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