HELP - Fuel Gauge issues

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