Forcing "A/C" idleup (to make my idle better).

[1LE]

Before I go to all the work to try and figure out how... Has anyone found a quick hack to make the ECU think that the A/C is on (when it isn't)?

My car finds the stock 750rpm to be just a bit low, easy to stall... The extra 100rpms from the car thinking the A/C was on would make it a lot easier to drive around town. I don't actually have the A/C anymore and don't mind cutting wiring. I'd expect there's a pair of wires I can short somewhere that will make the ECU think the A/C is on without actually attempting to engage the compressor or check the pressure sensors and switch positions.

 

[Staytuned]

Why not just adjust the BISS?

 

[steve]

Why not just adjust the BISS?

Because in order to get the idle speed to anything other than stock you have to drive the ISC out of range and that causes other problems.

Steve

 

[1LE]

Because in order to get the idle speed to anything other than stock you have to drive the ISC out of range and that causes other problems.

Exactly!

These problems include "ISC range error" MIL, fuel trim problems at idle, idle that varies based on the weather, idle surge, etc. (I have to RTV my BISS in place or it walks out and I've experienced all manner of idle problems from having the BISS in various settings other than where it should be!).

However, one *can* play around with the BISS a *little*. It won't affect the normal idle, but will affect how the car drops down to idle. It appears that when the throttle is closed, the car drops to near the base idle and *then* activates the ISC. Which means that if the BISS is too tight, the car will drop too far and be more likely to stall. If the BISS is too loose, you can actually feel the car surge if you're decelerating in gear and hit that rpm (even if you're still close enough for the ISC to be able to pull the idle down to 750)...

So, that was a lot of typing to further explain our Wiseman's point that the BISS needs to be set correctly or bad things happen.