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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: swilliams on March 19, 2015, 11:22:32 am

Title: Fuel tank sending unit
Post by: swilliams on March 19, 2015, 11:22:32 am

Hello I am in the middle of a gauge upgrade and am having problems getting fuel gauge to read properly. As i understand with the tank full it should read 90 ohms and empty 0 ohms. Well with a little over 1/2 a tank i am getting a reading of 145 ohms. I hooked the original gauge and it works fine showing correct level. Let me know what you think. Thanks

Title: Re: Fuel tank sending unit
Post by: Captkaos on March 19, 2015, 06:36:27 pm

Are you using a gauge different than factory?

Title: Re: Fuel tank sending unit
Post by: swilliams on March 19, 2015, 11:40:26 pm

I am using speedhut gauges. The fuel guage has several preset ohm ranges. I just dont understand why i am getting such a high ohm reading on the stock wiring from the in tank unit.

Title: Re: Fuel tank sending unit
Post by: Captkaos on March 20, 2015, 05:47:26 pm

Is the guage set to read 0-90? 

Title: Re: Fuel tank sending unit
Post by: swilliams on March 20, 2015, 05:54:24 pm

Yes it is. I spoke with speedhut and they told me that they recommend me using the same ground as the sending unit.

Title: Re: Fuel tank sending unit
Post by: Captkaos on March 20, 2015, 05:56:01 pm

were you trying to ground straight from the gauge to the body?  If so that could cause it.  Problem is, you will need to run the wiring from the back to the front.
If I am understanding this right.

Title: Re: Fuel tank sending unit
Post by: swilliams on March 20, 2015, 06:02:43 pm

Yes that is what i was trying to do. I will run the wire from the gauge to the same ground. I did not have the same issue with the other gauges. Hopefully it works that is all i need to finish the install.