Is there a later version than 2.886 that has the code to set the pintle on a GM IAC to a known "Start Value" - This is the number of steps (user selectable) that the valve will move, towards closing, at "key on", so that the pintle is closed to ensure it's closed, before the pintle is properly retracted towards opening so that the engine will "cold idle" reliably each time the engine is started while cold? I'm not sure the wording is correct, but, if I start my car on a cold morning and then realize I forgot something locked in the house, I shut off the engine, go in the house, come right out and restart the engine. It now idles very high as the IAC has opened to start the engine the first time, but the engine was shut off immediately. That left the pintle open maybe 60 steps. Then when I started it the second time it got another 60 steps. Now it's 120. That makes for a high idle! So, is there a version that forces the pintle to close, say 50 (user selectable) steps before it is then commanded to open to the proper 60 steps? I once did 3 key-on / key-off cycles and when I finally started it, boy, did it idle high. I now set my fully closed setting to 250 (it used to be at 180, that wasn't enough for this scenario) to make sure after it has warmed up that it is for sure closed. Even if I did a couple key-on / off cycles on a cold engine.
Thanks
Holl
Start Value to close the IAC for consistent starting
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
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Mike Hemingway
- MegaSquirt Newbie
- Posts: 8
- Joined: Fri Mar 25, 2011 4:55 pm
Re: Start Value to close the IAC for consistent starting
Hey Holl,
I am also using a GM IAC on a 5.1L V-8. It works fine and I can turn the key on/off many times and still get the correct value at a start.
The values I am using are -40 F has 40 steps and 180 F has 250 steps. The curve shape is almost linear between those values.
I am using IAC always on, start retract =250, crank pos = 255 and C to R = 2 seconds.
I had to play with the values to get the pintle to fully close then re-open to the correct step at each key on. I followed the Megatune manuals advise which was helpful.
Hope this helps, Mike
I am also using a GM IAC on a 5.1L V-8. It works fine and I can turn the key on/off many times and still get the correct value at a start.
The values I am using are -40 F has 40 steps and 180 F has 250 steps. The curve shape is almost linear between those values.
I am using IAC always on, start retract =250, crank pos = 255 and C to R = 2 seconds.
I had to play with the values to get the pintle to fully close then re-open to the correct step at each key on. I followed the Megatune manuals advise which was helpful.
Hope this helps, Mike