another fuel gauge issue

[2008srx]

first post for me, put in new gauge on a '69, and new sending unit. Fuel gauge reads below empty, When i disconnect sending wire in trunk, gauge go's to like 1/4 full only. when i ground the wire, it go's to way past empty. Anyone have any ideas? thanks

[chevymaher]

Is the ground wire good not dirty?

[2008srx]

yes, tank and ground wire are new. just did an ohm check from ground wire to connector in trunk. only got a reading of 1.4 with 4 gals of gas, thinking it should have been like 18? i saw some posts where the sending unit is grounding out internally even though brand new?

[shadowgray396]

At empty it read around 2 ohms, half full at 40, and full around 80 to 84 ohms. Did you do a ohms check of the sending unit before you put it on? Also if you do a search on here on fuel gauge there several right up about it

[chevymaher]

yes, tank and ground wire are new. just did an ohm check from ground wire to connector in trunk. only got a reading of 1.4 with 4 gals of gas, thinking it should have been like 18? i saw some posts where the sending unit is grounding out internally even though brand new?

It is grounded to the pickup unit that slides into the tank. And that is grounded to the body. So another check is body to battery. Is that grounded?. My car had 3 factory and has 6 now, I tend to be overkill on that stuff.