So, I've installed my MS2, and I'm proceeding with basic tuning, idling, etc.

I finally got it up to temp, and the fan never came on.

The stock ECU has been relieved of all its functions with the exception of controlling the AC, the Alternator, and the Cooling fan.

At the moment it is failing to control any of these things.

Question:

What sensors at minimum still need to be going to the stock ECU to keep it happy enough to still think it is running the motor?


More Info:

I was running with the stock MAP and IAT unhooked. I still have them both installed, but the wires were unhooked and I did not realize until later that I should try with them to see if it makes a difference.

I have the MS2 ECU's fuel pump relay wired to also power up the ASD relay. I was able to jumper out the fan relay, and the fans come on, so I don't think it is a problem with the system power. My MS ECU relay gets power off the ECU power pin, so the ECU is powered up as well (and I have a CEL on). I can scan it, but I know the ECU is pissed in general, so I'm not sure it will help a lot.

One more question:

If this is not something easy to fix, I am considering going full standalone and controlling the fan with the MS ECU. I can run an external regulator for the alternator, so that leaves only the AC.

Am I missing anything? Is the AC easy to run without the 'ac control' stuff that MS3 offers?

Thanks guys.