trying to diagnose gauge / sender failure

[80convertible]

My 1980 has an oil temperature gauge. I purchased an AC Delco oil temp sending unit. To date I have not been able to get the gauge to work. The needle pegs all the way to the right if I ground the sending unit wire. I confirmed that the sending unit resistance (Ohms) drops when heated (used boiling water as a test). I confirmed that the wiring is o.k (made my own wiring harnress). I still am clueless as it relates to a failure of the gauge or sender. I don't know what else to do to diagnose the problem. Any help is greatly appreciated.

 

[curtis]

doesn't sound like a guage problem since it pegs on grounding the wire. The resistance range for the sender must be out of wack for the guage. Get to a real auto parts store that has books and they can look up the ratings for the part you should have and cross it over to something very similar or exact. Possibility you used too much sealant or teflon tape on the sender and it is not making a good ground to the block.

 

[80convertible]

doesn't sound like a guage problem since it pegs on grounding the wire. The resistance range for the sender must be out of wack for the guage. Get to a real auto parts store that has books and they can look up the ratings for the part you should have and cross it over to something very similar or exact. Possibility you used too much sealant or teflon tape on the sender and it is not making a good ground to the block.

Thanks for the response. I did not use any teflon tape or sealant. Even if the resistance range is out of wack, I would think the gauge would read something..just not necessarily the correct temp. In my case, I can't get the gauge to read anything.

 

[curtis]

Is it possible the guage is not in the hot oil, and thus the reading is below the lowest level of your guage? Hard way to do it butt, you can pull the sender and hook a ground wire to it then stick it in the hot water with switch on and see if guage reads then. Other than that I am at a loss for you. ps I had a water temp guage act like that once. I turned out to be an idiot light sender in stead of guage sender.