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Discussion Starter · #1 ·
Does the gauge go down to E when the key is shut off? I filled my tank just recently it went up to F but with the ignition off it stays there. is there anyway to bench test the gauge?
 

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A couple of resistors should do it to simulate the sender. 45 ohm is half tank, 90 is full tank. Remember that gage doesn't have a ground wire. Need to ground it's frame to provide ground to the meter.
 

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Mine gauge just kind of stays wherever it feels like when the key is off. It doesn't go down to E like the newer cars when the key is off, but is pretty accurate when the key is on. You will find that it moves around a lot when you are climbing hills and accelerating quickly.
 

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Discussion Starter · #4 ·
Thank you guys, I just went and got some resistors from our electrical dept. I dont have the gauge or wiring diagram with me but is there only 1 power wire for the gauge, also do I put 12v through the resistor and touch the gauge? I noticed the gauge has a little coil thing on the back of it.
 

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Back of the gage has 2 wire. A black/pink and a tan.
Black/pink is 12 volts.
Tan is the sender lead.
Frame of the gage is ground.
The tank sender is a variable resistor that goes from 0 to 90 ohms. When the tank is empty, the sender reads 0 ohms. When it’s full it reads 90 ohms.
So with the sender wire disconnected:
Shorting the gage sender lead makes the gage read empty.
Putting a 45 ohm resistor between the gage sender lead and ground makes the gage read ½.
Putting a 90 ohm resistor between the gage sender lead and ground makes the gage read full.
 

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Discussion Starter · #6 ·
Thanks John your awesome. I will do the test tonight if I can tolerate the smoke smell in the garage. Im tired of fires. Thanks again.
 

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Ya can't get away from the smell anywhere lately. Heading over to Chatsworth in the morning. Hoping the 118 stays open.
 

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Discussion Starter · #8 ·
Okay I just tried the test and I put power to the gauge and as soon as I grounded it, it went to E. I touched the resistor to the sending lead and ground and nothing happened, maybe I dont have the correct resistors. If I disconnect the ground and hook it to the resistor then touch the sending lead it goes to F. Tomorrow I will check to see if I got the right resistors. Thanks.
 

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Hey big on my 65 my gauge stays at the amoun i have it doesnt go down at all and it is very accurate.
 

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Need to make sure the meter has a ground. The fuel tank sender wire needs to be disconnected from either the gage or the sender. The resistors go in it's place.
 

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Discussion Starter · #11 ·
This is what Im doing, I have the gauge out of the car and Im checking it on the bench using a 12v power source. I hook up power and ground the frame, then I touch the resistor lead on the gauge with the resistor then ground the resistor. The resistors Im using are 41 and 90 ohm, they are 1/4 watt also, does that make a difference? I noticed they did get a little hot.
 

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1/4 watt is too small. They should work for a quick test but will get hot in a hurry. Get above a watt. Sounds like you are doing it right.
 

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Discussion Starter · #13 ·
I just got some new ones, they are 2 and 5 watts. Were the 1/4 watt resistors overheating and not giving the proper resistance?
 

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Discussion Starter · #15 ·
Well I tried again with no luck, Im going to take it to work and have a electrical guy check it out. I know the gauge has to work because when you short the sending circut it goes to E. I will post back in the morning.
 

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Discussion Starter · #16 ·
Ok heres the verdict, the gauge works fine. What I was doing wrong was I had the power source hooked up backwards. Thanks again.
 
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