I have placed it along with my AutoMeter sender in the upper radiator hose. I cannot get my gauge to read higher than 150 degrees F. Maybe this is the incorrect placement? Like the water had already been cooled from the radiator and I'm reading the cooled temperature? Do I need to put it in the long one that connects to the thermostat housing?

That is where it should be.

Make sure all your connections are solid and that your grounds are proper..

It should hit 175 pretty much as soon as the thremastate opens. Did you hook a ground to the adapter?

No. Do I need to ground the nissport adapter itself? How would I do so? Would solder hold up to the heat?

Just get some 14gauge or so wire and crimp on a couple ends. The adapter has a bolt for you to use. Simple.

Yeah they supply a spot on the adapter for grounding purposes ;)

Well I was not aware of that :)

Borrowed Ben Moses's Techtom along with grounded that thing and they match well. :) Thanks for the tip. I was able to get it to max out at 181 degrees according to the Techtom. Is that low? It's in the mid 60s here and I drove around for probably 30 minutes.

That sounds about right (or at least my MDM usually sits around 178-180 in normal driving). Let it idle at a stop or something and see how high it will go; my fans kick in at exactly 212.

I seldom get over 180-190 unless the car is not moving. Sounds about right to me also.