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Poll

i just put a box on my hd and took out the rear tank anyone know how to wire it so the gas gauge will work

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Author Topic: gas gauge  (Read 3051 times)

mrhd

  • Single Axle Driver
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  • Posts: 21
gas gauge
« on: October 18, 2011, 09:00:16 AM »
Gas gauge gives me a different reading every time I start the truck

ED-NY

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Re: gas gauge
« Reply #1 on: October 18, 2011, 02:02:26 PM »
First thing I would do is re-establish the tanking sending unit ground. Then monitor the ohm resistance at the tank to verify that the sending unit resistance is constant as compared to the dash gauge. If the tank resistance varies..probably a sending unit problem. If the resistance is constant...then the wiring up to and including the gauge needs to be checked....but make sure you have a good clean ground. 

The GM 0-90 ohm 2-1/8" fuel display gauges aren't very expensive and easy to install.

Good luck

mrhd

  • Single Axle Driver
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  • Posts: 21
Re: gas gauge
« Reply #2 on: October 21, 2011, 10:01:43 AM »
I put a brand new sending unit in and used the frame as a ground..... I have a gauge cluster sitting around I'll try swapping them

mrhd

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  • Posts: 21
Re: gas gauge
« Reply #3 on: October 21, 2011, 08:40:50 PM »
Tryed other gauge cluster and no change it's like it almost vibrates wile the trucks running this things making me go crazy

ED-NY

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Re: gas gauge
« Reply #4 on: October 21, 2011, 09:12:08 PM »
I would hook up the ohmmeter to the unplugged sending unit and determine the resistance. You should be able to “guestimate” how much fuel is in the tank.

-0- ohm is empty -90- ohms is full - so half a tank would be around 45 ohm, see if that matches up with your tank fuel level.  You could actually use the ohmmeter as a fuel gauge.  If that end is working…..you need to check the wires from the sending unit plug up into the dash gauge.

I have seen corroded plug connections & broken wires (internally) near the plugs.

You may want to hook it back up and have someone watch the fuel gauge as you pinch/wiggle the wires from the tank right up to the gauge area in case you have an internal break. I saw this on a Ford Police cruiser once. Apparently someone probed the wires on an earlier occasion - road salt got in and corroded the wire. The fuel gauge was intermittent  ..depending on the roads bumps etc.

A_DAB_will_do

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    • Benson's Mobile Welding & Fabrication
Re: gas gauge
« Reply #5 on: October 23, 2011, 01:19:24 PM »
This is what the gauge does in my truck too.  With just one sender hooked up it never reads full.  With two new senders hooked up it never reads empty.  I'll take Ed's advice and start checking for bad wiring when I next have the time.  Till then, it's fill the tanks every 200 miles, just in case.

I would hook up the ohmmeter to the unplugged sending unit and determine the resistance. You should be able to “guestimate” how much fuel is in the tank.

-0- ohm is empty -90- ohms is full - so half a tank would be around 45 ohm, see if that matches up with your tank fuel level.  You could actually use the ohmmeter as a fuel gauge.  If that end is working…..you need to check the wires from the sending unit plug up into the dash gauge.

I have seen corroded plug connections & broken wires (internally) near the plugs.

You may want to hook it back up and have someone watch the fuel gauge as you pinch/wiggle the wires from the tank right up to the gauge area in case you have an internal break. I saw this on a Ford Police cruiser once. Apparently someone probed the wires on an earlier occasion - road salt got in and corroded the wire. The fuel gauge was intermittent  ..depending on the roads bumps etc.

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mrhd

  • Single Axle Driver
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  • Posts: 21
Re: gas gauge
« Reply #6 on: October 23, 2011, 11:34:17 PM »
OK so I was told the purple wire in the harness under the cab was the gas gauge wire so hooked a wire from the small gray wire off my sending unit to the purple wire just under the mastercylinder and no change I might just have to buy an aftermarket gauge n try and make that work I'm going crazy haha

 


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