Low Fuel Module - Team Camaro Tech
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post #1 of 5 (permalink) Old Sep 11th, 18, 10:27 AM Thread Starter
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Bill
 
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Low Fuel Module

Hi everyone, is there anyway you can check the low fuel module when it is still in the car hooked up? Thanks for any help.
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post #2 of 5 (permalink) Old Sep 11th, 18, 03:47 PM
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Jim
 
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Re: Low Fuel Module

I believe you could with some different value resistors, disconnect the sending unit in the trunk, turn the ignition on, and then with different resistors connect to the wire end going to the gauge through different value resistors to ground to see at what value the light would turn on.

If the light was designed to come on at let's say 1/8 full tank (and the fuel gauge system is of a 0-90 ohm design), then a resistor value of around 8 to 11 ohms should turn the light on and have the gauge reading about 1/8 full or a tad less and then if this resistor was changed to a 22 ohms then the light should go off and the gauge reading about 1/4 full.

Jim

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post #3 of 5 (permalink) Old Sep 11th, 18, 11:59 PM
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Brian
 
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Re: Low Fuel Module

Yes Bill you can bench test a LFWM using a 0-100 potentiometer or higher in place of the tank sender signal. Your multimeter on Ohms will tell you the trigger point.

There are a couple old threads in the archive mapping the default set point of original 67, then 68-69 GM units used in Camaro and also popular replacements from OER and CHQ as well as the variable units where you can pick any set point you want.

Most of the factory units for GM vehicles were 1/8 tank or less, so as Jim says 8 to 10 Ohm's. On modern fixed point replacements around 1/4 or less. Some units were rapid fire, others slower to react due to complaints about flickering as fuel sloshed around in the tank on corners, so give it a few seconds once you have selected a value to test.

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post #4 of 5 (permalink) Old Sep 12th, 18, 09:50 AM Thread Starter
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Bill
 
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Re: Low Fuel Module

Thanks for the replies. I have a extra sending unit that is out of the car. could I just hook that up and move the float to give me a low fuel light?
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post #5 of 5 (permalink) Old Sep 12th, 18, 10:37 AM
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Jim
 
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Re: Low Fuel Module

Quote:
Originally Posted by birds69 View Post
Thanks for the replies. I have a extra sending unit that is out of the car. could I just hook that up and move the float to give me a low fuel light?
That should work providing it's good and you also connect the ground as well as the signal off of the sender to the gauge and low light module. You will also need to have the key in the run position as the gauge only works with the key on and it getting power. Just saying this as some people assume the gauge works all of the time.

Jim

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