ISCV update:
Finally had time to work on the idle air control valve. I looked up the schematics on some pages and it seems like center wire is +12V and one wire closed the valve, while the other one opens the valve.
I then tested it with a 9V battery, putting + in the middle wire. Then tested each side to verify which one is which.
Looks like on the BMW harness, white/red is the +12V, white/yellow is open, white/green is the close.
Firstly, I needed to take off the old nonfunctional thermostatic idle up valve. Taking it off felt like surgery. I was delicately unclamping the hose clamps and plugging them up so the least amount of coolant leaked out. I also took the negative battery terminal off and put some plastic over the alternator (lesson learned from last time)
Here's the old idle valve. I looped the coolant nipples with the original hose.
![Image](http://i.imgur.com/gDSLkXJl.jpg)
I cut the other hose so it makes a nice small loop.
![Image](http://i.imgur.com/tj4coFol.jpg)
Here's my new setup. I modified the support bracket and secured it to where the GTS coolant overflow used to sit. Don't mind the electrical tape. I'll find a way to step down from the ISCV to the hose connecting to the vacuum distribution box. This is just a testing rig.
![Image](http://i.imgur.com/K2CMxMSl.jpg)
It took a lot of trial and error with the "period" or pulse. The default was 0.0ms, which is suspiciously wrong. I looked up a bunch of places and it seems like stepper motors are around 2-6ms, I couldn't find any rotary type numbers in the moment. So I tried 6ms, and then 2ms, then 10ms, none of them worked. I got pretty defeated after that. Turned off the engine, double checked the wires. I was wondering if the numbers were too low, since the manual says 0-50ms. So I maxed out the number. It didn't do anything while the engine was running. I turned off the car and started it up again. This was what worked initially! I took a peak at what the rotary valve was doing and it was fluttering about. So I repeated the process with 30ms, then finally 20ms. Which seemed to be a good spot for it.
I then adjusted the idle section of the fuel map, and the fuel post start enrichment map, and fuel-coolant priming map.
Also adjusted throttle pump so they work with the new setup.
Anyways, with a lot more tweaking I got this during hot start:
https://www.youtube.com/watch?v=aMYQhJGHhMgIt idles at 878rpm + 314rpm (start)
Will test again once the engine is cold.
EDIT:
Measured some of the sizes.
Bosch Idle Valve measured in diameter:
Air inlet: 26.5mm with ridge at 27.5mm
Outlet: 24mm with ridge at 25mm
Vacuum Distribution Box hose:
inner diameter ~8-9mm