MS IAC control

[323driver]

Anyone running an IAC with MS2? It's getting really cold here in the mornings and It's really hard to start the car without the IAC since I have the coolant air valve removed and need to hold the gas pedal to avoid stalling.

Could somebody having a startup idle of roughly 1500 share their settings for the IAC?

Would be much appreciated

Thanks

[Lex]

I run it with MSI

[323driver]

It seems to me that whatever settings I try, it doesn't affect the IAC valve. Can somebody share their IAC control settings?

[therieldeal]

i have the same problem. it seemed to work briefly then stopped. i figured the IAC broke or i had a bad wire...

[323driver]

No one can share?

[Lex]

I don't have mine here at work. However, make sure you run a diode across the power and signal lines to the IAC. Also you have to have the correct PWM driver installed in the MS - the one that comes with the kit is not sufficient to drive our IAC.

[Beerizfood]

+1 on the diode and make sure it faces the right direction.
I use PWM warmup.I found that the valve worked in reverse to the software so i had to set the warmup table upside down.My valve is off at 100%.
Im using MS extra and its nice to be able to set the frequencey of the valves operation to reduce operating resonances.

[Shades]

I forget what I set mine to... but it's either on or off, it doesn't modulate.

[323driver]

Yeah, I did change the driver for a tip 120 and added a flyback diode across it. With the Cranking pulsewidth set to 90%, it now starts at 2000 rpm. The warmup pulsewidths are set from -40deg:90% to 70deg:2% but once the car starts, the rpm drop and it stalls , like if the code doesn't use the warmup IAC table but just the cranking IAC value. The frequency is set to roughly120 HZ, I'm thinking to increase it and try again.

Is the warmup enrichment important? I left mine at the default values and the car is at 11-12 AFR when warming up. Should I leave it like this or reduce it to get roughly 12.5-13 AFR?

Any ideas?

[323driver]

still the same problem, the MS doesn't transition smoothly from cranking to warming so it always takes 2 starts to get the car running and the IAC stays at 1500 or whatever it should be. I think I will reconnect back the air valve, maybe that would solve this issue. MS was definitely not developped in Canada, I wonder how it will be at -30 in winter.

[Lex]

Can you change your idle speed by playing with the duty cycle of the IAC in megatune?

[323driver]

yep, I can set the IAC duty cycle to whatever I want.

I used the stock configuration to set it up. Disable IAC and set idle to 1100 rpm with the screw. Then connected the IAC and set duty cycle to roughly 25% WARM so it idles nicely at 750 rpm and to 60 (I think) for coldest (-40). Interpolate in the middle between 60 and 25 and you get your warmup rpm at different temps.

Cranking duty is set to 60 as well so it turns at 2000 rpm and tapers in 5 secs.

I have afterstart set to off, maybe that is the problem.