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Just curious if anyone is running their Megasquirt with A/C?

Why would it matter?

You should wire MS in so that you keep the stock ECU for IAC/A/C Cruise, etc.

If you completely remove the ECU i believe you cannot retain everything.

Daninski wrote:Why would it matter?

because I have A/C, and would like to retain my A/C when I decide to run MS. And just seeing how others on here have ran it.


@ onlytrue:

I noticed through search that you had to run the stock ECU for IAC/AC/Cruise, but just curious as to how you did it. Like.. did you retain the stock wiring harness, but "splice" some sections for the harness away from the ECU to megasquirt?

I just wired in the stuff that MS runs, and left the A/C, cruise, and such in the ECU. I did it with what turns out to be crappy connectors (The crimp kind). It's run flawlessly for over a year now. You can run the A/C, and stuff with MS, but I don't know how. I'm trying to figure out how to get it to run the MSD6A box.

okay awesome! I know pretty much how to do it then lol.

and yeah I think when I do my wiring i'm going to solder the wires together and use that shrink wrap over to the solder point.

And yeah it would be nice to eliminate the stock ECU, but I will need the IAC and A/C. Don't have cruise so that's no big deal...

Yeah I have not done it myself, I've just read up on it.

I could not live w/o cruise, and am upset my a/c is broken. W/o cruise control I get tickets!

I'd thoroughly recommend soldering. The crimp sets and tap things are good to test and get started but I've had some issues with them, particularly on the very light guage wire. As said just use MS for that which you'd like to customise. Remember though, if you grind a crank tooth off for running single trigger your AC will not work apparently, nor any other ecu features (VRIS etc). Dual trigger setups are fine though, as the crank pulley stays stock.

I recommend some decent quality automotive connectors should you wish to keep things removable. I have mine setup so I can plug the injectors back into the stock ECU with just one 6 terminal plug. It's saved me a few times already!

^You make some very god points.

When I move to MS, I will definitely want to have everything on some sort of plug system. Never know whats gunna happen!

yeah i am getting up some idea for wiring.

I'm only using megasquirt, btw, for a turbo build I'm going to do on my BP. Trying to run around 8-10 psi of boost, and am going to use MS for the air/fuel ratio and to keep the car running smooth with the added psi.

Just so you know, I'm not running my IAC. You don't need it with MS. I have it blocked off completely, and the car idles rock steady, even if freezing temperatures. I have the CTS inline where the hoses would go into the TB.

fowljesse wrote:Just so you know, I'm not running my IAC. You don't need it with MS. I have it blocked off completely, and the car idles rock steady, even if freezing temperatures. I have the CTS inline where the hoses would go into the TB.

Yeah I've seen people make IAC Blockoff plates. Is there anything special in order for MS to run the idle?

Jesse does not not live in freezing temperatures, I would not recommend blocking the IAC in colder temps like we have in the north eastm rather than the 5 days of cold they have in portland haha.

I have ran with the iac and coolant lines blocked, and had issues in cold weather starting. By cold weather I mean temperatures BELOW 0.

Surmising by your post "When I move to MS...", you do not have MS yet. As mentioned, I have started the car in freezing temperatures, with no problem. MS enichens the mixture however you program it to. It doesn't matter if it's one day a year, or 364½. If it starts in freezing once, it always will I don't know if will make a difference if it's 29°F, or 0°F. If you live in 0°F, you could easily find out if it will work.
You don't need anything extra to block off the IAC. MS is set up to run without IAC.

I'm going to look into it more but looks like something simple to do.