1. Rebuilt the throttle body - No change
2. Brand new OEM IAC Valve - No Change
3. OEM Intake Manifold - No Change
4. Replace all Gaskets related to intake manifold and throttle body - No Change
5. Spend hours adjusting the BISS and the tune - No Change
So as a last resort, I pull the IAC valve out to see what it is doing. When the motor would "park" it extended the plunger to the max. When the valve was out of the TB it was not an issue. Once the IAC was in the TB and the park happened I could hear the IAC clicking. This was the gear drive on the inside skipping teeth. Changing the "Idle Stepper max steps" did not affect how far the "park" would drive the plunger.
So in order to fix the skipping teeth issue I wanted the "park" to bottom out the plunger. To accomplish this I needed to move:
C1-69 to C1-70
C1-70 to C1-69
C1-71 to C1-72
C1-72 to C1-71
This will now drive the IAC in the opposite direction. So when the "park" function happens it now bottoms out the IAC. I then needed to check "Idle Airflow Invert".
After this was completed I am now able to get the car to idle at 1000rpm, and start and idle every time.
1. Pull the idle motor out of the throttle body, leave it hooked up to the connector.
2. Put the car to the on position, wait 20 seconds and measure the position of the plunger or take a pic with your phone.
3. Remove the key from the car, wait 20 seconds and measure the position of the plunger or take a pic with yoru phone.
4. If the plunger moved to the bottom of the idle motor when the key is off, then everything is configured correctly.
-- You will need to adjust the max limits, ignore further steps
5. If the plunger extends all the way out this could be the source of your problem.
-- Measure the max length of the plunger extended all the way out, then measure the depth of the hole that the plunger sits in. If the lenth of the hole is less than the length of the plunger then your idle motor is hitting a mechanical stop, and the idle motor could be skipping teeth screwing up the position the aem thinks it has the motor in.
-- This will require the wire swap, the wire change will simply drive the motor in the opposite direction. So when the park command hits, it shoudl bottom out the plunger to the idle motor.
6. Find the max value. Using the measurements from the hole and the plunger, start to adjust your Idle base Settings until the plunger is at the max depth for the hole. You now have your max Idle base setting.
7. Turn the car completly off, pull the key out waite 5min, put the key back in the car and watch the idle motor again. Did everything work as expected? Did the plunger go to the position it was supposed to?
-- If so you are ready to put the motor back in the car, pull the key out and put the idle motor back in the car.
-- If not redo steps 6 and 7 until you are good.
8. Everything is back in the car. Start it up and tune your idle. The only reason to check invert airflow is so that a lower number in the Idle Base Setting table will result in a lower idle, and a higer setting will result in a higher idle.
Other items, you might have to much PID going on in your idle. For me on the Evo 8 I am running p=.001, I=.005, d=.002. For the ignition it is p=.000, I=.00, d=.010. So the PID setting might be to agressive.