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Megasquirt and A/C
Posted: Tue Apr 27, 2010 7:55 pm
by poordude2151
Ok I have a 1993 Toyota tercel and on my wiring to the stock ECU on the 16 pin plug I have 3 pins I am not sure if I need to connect them to the MS II 3.57.
The pins are:
6 AC2 12v power to aircon computer
14 ACT A/C Cut Control System
15 AC1 A/C Switch Signal System (12v to Aircon Computer)
Should these be connected for the a/c to run properly?
If so How would I go about doing that?
Thanks,
Billy
Re: Megasquirt and A/C
Posted: Wed Apr 28, 2010 4:45 am
by Matt Cramer
Not 100% sure but most Toyota A/C systems work fine on their own without being connected to the ECU.
Re: Megasquirt and A/C
Posted: Wed Apr 28, 2010 6:38 am
by poordude2151
If I was to have to run these to the MS how would I do that?
Re: Megasquirt and A/C
Posted: Wed Apr 28, 2010 9:36 am
by V6 SPL311
On my Toyota, when the AC is on, the idle is kicked up a couple hundred RPM. So...
I would hazard a guess that a FIDLE circuit would be appropriate. Should be the only reason the ECU knows the AC is on.
Re: Megasquirt and A/C
Posted: Thu Apr 29, 2010 4:13 am
by Matt Cramer
poordude2151 wrote:If I was to have to run these to the MS how would I do that?
You wouldn't.
Re: Megasquirt and A/C
Posted: Fri Apr 30, 2010 7:47 am
by poordude2151
So another words I wouldn't be able to if I had to for the A/C to work?
Re: Megasquirt and A/C
Posted: Mon May 03, 2010 5:41 am
by Matt Cramer
The MegaSquirt does not control A/C with current release firmware. You would need to devise an alternate means of making the A/C work. As automotive A/C has been around a lot longer than workable EFI systems, it's not like you need anything very complicated, a few relays at most.
Re: Megasquirt and A/C
Posted: Fri May 07, 2010 5:03 pm
by drmiller100
AC can be REALLY simple, or stupidly complicated.
ultimately, to make the AC come on, all you really have to do is energize the compressor clutch with 12 volts.
You might cycle that clutch to keep the inner evaporator (core under the dash which makes the air cold) above a certain temperature so that it does not ice up.
Or, you can just watch the pressure on the low side to keep the low side pressure above a certain point (more common.)