Problems with Bosch 2 wire PWM Idle Valve

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davezed
Helpful Squirter
Posts: 41
Joined: Mon Nov 01, 2004 12:11 pm
Location: Australia

Post by davezed »

Hi g60peru
I think you will find the only value that effects PWM is the freqency (under the control menu), the other stuff is for 4 wire only. If you look here http://www.megasquirt.info/megatune.htm#sd I think you will find anything that has "IAC" next to it implies 4 wire only (the other stuff probably could be greyed out). The page you need is under Tables => Idle PWM Duty Cycle, here you set how your PWM functions, ie the duty cycle. MS manual again has some info on this http://www.megasquirt.info/ms2/ => look for On-Off/PWM FIdle Valves on the LHS of screen.

Cheers
DaveZZ
CSM
MegaSquirt Newbie
Posts: 18
Joined: Sat Nov 28, 2009 6:38 pm

Re: Problems with Bosch 2 wire PWM Idle Valve

Post by CSM »

I know this post is old, but I've ran into these sort of issues today. So originally my engine had a stepper motor because of space constraints (its a 50 cc). Since I'm running microsquirt, I made a frankenstein PWM IAC valve out of the original pintle and a briggs and stratton fuel shutoff solenoid. I test it with 12v and it works great. The pwm control settings didn't work, so I tested it with "solenoid" idle control in megatune, and this works properly. I noticed the pwm % was 100, so I changed the "IAC start value" to 100% for the pwm IAC settings. I tested it again, but Megatune still said 0% when microsquirt was first powered up, so i'm not sure if this works. I wish it would, since I don't like having to wait for it to read cranking to open up. I could use "solenoid" settings, but from my understanding, this just stays full open until the engine is warm to a certain temp. If I do this, my engine will run at 5000 RPM. I need the full open length to start the engine. Would looking at the code be best?
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