FC3S Idle valve for air-conditioning
 

Hi,

I have a FC which has been recently rebuilt, running on microtech LT10S and tuned in stock setting with no BAC and ACV valve. Due to the tropical climate in my region, I am planning to reinstate my AC unit onto my car and for the AC idle up, i am using a universal valve which has a screw adjustment for the flow. My question is that since the ecu has been tuned without AC, if the universal valve is used for the idle up without altering the ecu setting (injector pulsetime / timing), will it do any damage to the engine?

Thank You in advance,

Mike.

I'm not super particular with the Microtec stuffs, but generally speaking: If you increase the idle by adding air to the manifold, on a MAP based ecu, this will make the ecu read values from a different area of the map (higher RPM with the same manifold pressure). If your timing and fuel values were already appropriate then you should have no issue. If not, you might end up in a lean condition which isn't as dangerous at idle as it is at load.

Where you might come into issue is tuning for the load change from turning the A/C on and off or turning the fans on and off. Those two... ARE.A.BITCH

Thank You for your point of view. Strongly agree on your point on tuning for the load change from turning the A/C on and off. As for the universal valve connection, do you happen to know where i can locate a ac signal to turn on the valve. I have try to connect a relay in series with the ac main relay but it didnt work. Anyone has any idea on this.

Thank you in advance.

Mike.

Mikey,

I have the same issue as yourself. I've been working with simply using the aux input, which I advance the timing 10 degrees at idle, and triggering it with headlights and A/C.

https://www.rx7club.com/microtech-11...hts-c-1026098/

I just now installed a Dorman 911-800 Purge valve( for a Hyundai) onto a larger vacuum line coming off the upper intake manifold.
So far so good. it bumps up the idle about 250 rpms or so.
Now if I adjust the AUX input settings to adjust for fuel and timing correctly I should be able to
get a nice bump and dial it in nicely.

I plan on adding a thermo-switch to allow warmup function.

This is just my preliminary findings. But, so far so good.

Cheers,

Joe