IAC Valve to Elevate RPM When A/C On

[Uwon]

Originally Posted by Speedy Squirrel

You didn't elaborate too much on what you did previously to implement the Tech3R IAC based AC control, so sorry if this redundant:

1. Make certain that you don't have any vacuum leaks. A large leak can use up a lot of the rotary idle control valves range.
2. Make sure the rotary idle control actuator is not hooked up backwards using the Tech3R actuator test capability. It should open with increasing duty cycle.
3. Using the Tech3R actuator test capability, establish the minimum and maximum pulsewidth. Do this by observing the pulsewidth below which the actuator does not close any further, and above which the actuator does not open any further.
4. When FULLY warm, the engine should be able to idle with the rotary idle air controller disconnected. If not, use the idle adjustment screw sticking out the side of the throttle body to achieve idle. In very rare cases, it may be necessary to drill a hole in the throttle plate to achieve a good idle.

Now you have the full range of the rotary idle controller to use with the Tech3R idle AC table. This is more than enough to compensate for any AC load.


Also keep in mind that, if the spark timing at idle is ridiculously retarded or advanced, you may have problems with the steps above. Somewhere around 5 - 10 degrees of advance at the crank is the right amount.

OK, new one on me. What is a “rotary idle controller” as applied to the tec3r?
1. Done.
2. I have a two-wire Bosch IAC. Does not matter which way it’s wired. Works fine either way-good steady idle with or without IAC operating. In my case IAC is primarily used to catch motor on desceleration.
3. See 2 above.
4. See 2 above.
All I want to achieve is a higher idle rpm when A/C is on, so I can have cooler air while in traffic. The tec3r has a programming provision to increase rpm at idle when A/C is on but it does not work or is inadequate for my motor. Electromotive has had it twice for repairs with no improvement.
I determined that opening the unused 8mm nipple at the base of the throttle body provides me with the required rpm increase. Hence this thread in a quest to find a suitable normally closed solenoid air valve to open in conjunction with the A/C compressor. Prefer Porsche, but if not, some other manufacturer..
My Pierburg valve has not yet arrived. Anxious to test it.
Johan