Very happy with an hour and a half of mostly sedate driving, with some short acceleration blasts. I installed the FM VMaxx setup last night and hit the road for my first real test drive. I’m going to switch the wires tonight, but has anyone used the 2 prong sensor for the gauge successfully? All that would need to happen would be that the resistance changes at the same rate as the real gauge sender, I don’t think that should be that hard. Which means I’ll have to get an adapter like this to work with the M12x1.5 hole in the rear passenger side head. However, I also bought the one spade sender for the stock gauge (pictured next to the correct tap and taps for other plugs in the block), but that thread is 1/8th BSP, which will of course work with 1/8thNPT. It is possible that I switched the wires that attach to the sender so the half of the gauge that is supposed to go through the thermistor and then ground goes straight to ground. The real Miata gauge sender just has one spade terminal apparently, but the one I got for Christmas is the same as the one for the ECU (the metripack 2 wire connector). The wires back and forth are fine, but I think I have the wrong sender. I noticed my (stock Miata) coolant gauge wasn’t moving, so I began to trouble shoot that circuit. Haven’t had it on the road yet to see what the resonances will be near the road but after revving the car up it isn’t raspy at all and has pretty good tone (I’d prefer a little more shriek but perfection is the enemy of good enough). I am extremely happy with how loud it is at idle, (BTW we need an exhaust sound clip thread) the motor is bone stock but I was able to talk at a normal level anywhere near or in the car. I really hate working in the 100+ heat but once you start you kinda get used to it. 2.5” to a Flowmaster Wye then a single Hooker Aerochamber 3' offset in/out muffler.

Ls1 coolant temp sensor wiring diagram