...And I'm curious, how did you guys install yours? Did you remove the stock gauge wire from the sender and replace it with the aftermarket one? Did you piggyback the new gauge off the old one? Did you use the factory sender or did you replace it with a new one? What I want is to have functionality of the aftermarket gauge while retaining the functionality of the stock unit, and also making sure the sending unit is reading correctly. Are these something that need to be replaced over time?

I just recently installed a dakota digital gauge cluster on my 87 IROC that included the water temp gauge. Some things I ran into..

- If it provides a sending unit for the gauge, it would be wise to use that sending unit. Your water temp sending unit may be located in a different place ( mine was in the front of the manifold right under the throttle body, and was simple enough to remove and replace)

- I tried to tap right into the cable that was going to the stock sending unit, but my gauge would not work with that. The stock cable was a 2 wire connection whereas my new sending unit plugged into the back of it with a single spade connection. I first tried putting both wires into the spade, but that didn't respond either. I ultimately end up running a wire directly from the new sending unit through the firewall to the control box (the dakota digital kit as a control box where all wires lead to it, and then it connects to the gauges with a single ribbon cable, makes for a clean install). In your case you may want to consider running a wire directly from the sending unit to the gauge itself.

Note: My stock sending unit connection had a yellow (data) and black (ground) wire. My new sending unit did not need a ground as it grounded itself to the block.

- Running the wire directly worked, but it didn't seem wise to leave the ECM out of the loop (regarding the water temp) so I made another spade connection with both the wire leading directly to my control box, and the yellow wire from the OEM connection in the same spade. Then I ran a grounding line to a nearby grounding point on the chassis to the black wire.

With this current setup, my water temp gauge works, and the ECM is not thrown out of the loop.

Just something to consider. ... I do have a tranny temp gauge, and and Air/fuel ratio gauge as well that are mounted in a 2 gauge pillar mount. I was going to tell you to look for one on ebay, but they want crack prices for these things... $50 for a 3 pod... right . Post in the classifieds (or even check summit perhaps)

Good luck on this, let us know how it goes.

Uhm, it sounds like you were going off the wrong sensor. The sensor located in the front of the manifold on TPI engines is the CTS which is how the ECM determines the coolant temperature. There is another 1 wire sending unit in the drivers side head which is where the actual stock gauge reads from. I just Unplugged the stock gauge and hooked my gauge in here. Tomorrow I will try going off this sender for BOTH of the gauges.

Bah... i'd love to tell you that your wrong, but I'd be lying if I did. Where does this CTS go... to the ecm as well? The reading seems accurate. It warned me when I started going real hot because my fan died... good grief..