Megasquirt Install 2G wiring question

[TealTalon]

I have been slowly pecking away at the finishing touches on this installation. I am suffering from severe wiring fatigue.

As far as the tach goes, I had a spare one of these Auto Meter 5897 - Auto Meter Phantom Series Tachometers laying around so I decided on building and using the MS tach output circuit. Information on this circuit was oddly hard to find. At least for me it was. So I thought I would dump everything here so maybe some other poor bastard wouldn't have to hunt it all down.
The circuit was built using the Proto area on the V3 board.

MSnS-Extra Hardware Manual

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And there's a nice little post about it here to clarify things a bit in case that diagram created in MSpaint isn't clear... Minnesota's Community of Neons! • View topic - Tachometer Output Pin MS Build

This gets a little confusing, the 2n2222a from top aspect (leads down), flat facing
you (writing able to be read),
Is left lead #1 to tach and 10k resistor.
2. (Center lead) to 1k resistor then the pinout on the PCB. We used JS0.
I'm actually not sure what "Output3" "Pin10" are.
3. Right Lead, ground.

So run a wire from 12v (We used 12c near the DB37) or from one of the
transistors on the heat sink. Solder the wire to one end of the 10k resistor.
Solder lead #1 AND a wire to one of your spare outputs near the DB37.
Solder the center lead #2 to the 1k resistor, the other end of the resistor
goes to JS0 or whatever you've selected.
Solder the remaining lead to wire going to ground.

I used a spare 10K and 1K resistor from the assembly kit I originally purchased from DIYautotune. The 2n2222a transistor can be purchased at radioshack in a pack of 15 transistors. My store had it in stock. NPN Transistors (15-Pack) - RadioShack.com While you are there grab a pack of breadboard jumpers for the wiring if you need them.

I got my 12V input from an unused transistor hole along the heatsink.
Q12 on the V3 board. Look at the back of the board and you will see to thick traces going to these holes. They both get 12v when powered on.

Ground can be found at the top of the proto area.

I fed the output to pin 3, Spare 1 on the DB37.

The DIYautotune harness is missing pins on the DB37 connector (I understand not putting a wire, but at least put pins there so I can add a wire) for the spares, so I guess I'll have to go to radio shack and get extra pins for the DB37 female connector to run a wire out to the tach. To test I just touched the tach signal wire to the spare out pin on the board itself.

 

[TealTalon]

I just resolved a severe overheating issue. Two laps around the neighborhood and it was filling the coolant tank. I'm not sure if this is the same with all cars, but with mine, sharing the GM coolant temp sensor signal with the stock ECU to get the fans to kick on did not work. The stock temp gauge sensor, as inaccurate as it is, was showing almost all the way to H before the fan kicked on while the megasquirt was reading 195+ degrees on the GM sensor. Re-connecting the stock coolant temp sensor back to the ECU fixed the problem.

I had read about having to calibrate the MS to use a stock sensor instead of the GM sensor. I think this shows just how different the readings must be between the two sensors.

I think that's it. The last gremlin. I can finally drive and tune it.