On the way to Moab last week, I had some trouble from the green car. I never have trouble with the green car. It's a Japanese car that runs like a damn Swiss watch. Or...usually does. I was having weird over heating issues. The stock gauge is kind of an idiot gauge in that it doesn't show true temperature values. It just lets you know when there is an issue on either extreme end. The needle on the gauge was indicating an overheating issue but the needle moved very quickly. Too quickly, I think, to actually be indicative of an issue. It would be odd for the motor to heat up 40-50 degrees in 5 seconds and then come back down to normal temp. My first thought was to either the gauge itself flaking out, the wiring, or the sending unit. After a bit of research, I found out that the sending unit for the gauge on this motor is actually the same one that communicates with the ECU and lets it know how much fuel to tell the injectors to spray based on the motor temp. This is really odd because I know I have seen a 2002 RS (same motor) that had a separate sending unit (single spade connector) for the gauge. Mine does not. I also replaced that sending unit several months back because of a weird start up issue that I was having on cold mornings so I was pretty sure it wasn't that.
Every time I had the over heat issue on my trip, there was no pattern to it (sometimes it would show higher temps while coasting down a pass) and each time it did it, I could pull over and turn the motor off for 5 minutes and all was fine. I find it hard to believe that the motor would cool that quickly if it truly was overly hot to begin with. Certainly, this could be a water pump, thermostat, or radiator issue but I wanted to rule out the electrical gremlin first. So I decided to install another water temp gauge. I considered just getting a cheap ass gauge from Autozone and wiring it up and simply setting it somewhere in the car but I can't do that. So I ended up buying a gauge from Prosport along with a gauge pod for the A-pillar. The next issue was where to put the second sending unit. The factory one is on the crossover pipe below the intake and, frankly, it's a bitch to get at and I would have to remove a lot of stuff to be able to drill/tap into it just so that both sending units could read the same fluid. In the end I decided that it didn't really matter what fluid the gauge read. I just needed to know if both gauges were going to fluctuate. So I decided to install a simple splice into the upper radiator hose (this is at least fluid that is coming right out of the motor).
I didn't take many pics during the install because there's really not much to see. I pulled the A-pillar, figured out where I wanted the pod to be, drilled some holes, installed some hardware, ran some wires under the dash, and put the A-pillar back in place. I was not really happy with the fit of the gauge pod but that's what I get for buying it off ebay. I did finally get it to fit pretty nicely after making some adjustments to it. Here it is all mounted up and, really done.
This is the splice kit I used. Just figure out where you want it, remove a chunk of hose and re-attach everything.
Oddly enough, while running wire to the engine bay, I happened to notice this vacuum line was disconnected from the idle air control valve. It was a bitch to get back (super tight space) so I don't know how this just popped off. It couldn't have. Not sure what to think. Also not sure why my car hasn't thrown a code either. I was hoping to reconnect it and have like 50 more horsepower but that didn't happen.
The Prosport gauge is interesting. It has 5 wires. One to ground, one to the sending unit (an additional ground coming off the sending unit), 2 for 12 volt power, and 1 for 12 volt power with the headlight switch. All said and done, the gauge reads white like the first picture but switches to red when you turn the lights on. Pretty cool. Normally, having a different color gauge than my cluster would drive me crazy but the next car I think I'll be getting has a red cluster and that's why I did it. Now I just drive and wait for the motor to show hot again so I can see if I'm looking for something bigger. I should also mention that these motors are prone to over heat issues when they get an air bubble in the cooling system so I burped the system after opening it up to install the splice. Now we wait.