Megasquirt wont come out of high idle till restart at 160 degrees. - Tuning Forum

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Megasquirt wont come out of high idle till restart at 160 degrees.
Wednesday, April 14, 2010 3:58 AM
I bought this car from a guy who had done the 3400 swap. It has a megasquirt computer in it. The problem I am having is when I start the car cold it idles at 2000rpm and wont drop by itself. After reaching 160 degrees or higher you have to restart the engine to get it to idle down. And sometimes it will idle down to around 1500rpm and once in a great while it will hit the magical number of 1000rpm. If anyone can help me out please do.

Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Wednesday, April 14, 2010 7:23 AM
Could it be a bad TPS or IAC valve on the throttle body?










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Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Wednesday, April 14, 2010 3:41 PM
both have been replaced in the last month. I should have said that in the previous post.
Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Wednesday, April 14, 2010 11:19 PM
Is megasquirt controlling your IAC?




I have no signiture
Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Thursday, April 15, 2010 2:49 AM
Yes it is. Megasquirt runs the entire engine. the old ECM has been removed.
Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Thursday, April 15, 2010 4:03 AM
I know the problem. Had the same thing happen to me.

Go into your IAC settings. Look at where it says "minimum step size" It's probably still set at 1 like mine was. This is too small and it makes the IAC just kind of jiggle, the MS has no way of telling, just kind of assumes that it moved. The minimum step size on mine is set to 7. So I know you can go that far, not sure how far down you can go and have the problem not come back.

Then just adjust your curve from there til you get the results you want. You might have to play with it some for a while in different weather conditions.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick
Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Friday, April 16, 2010 3:19 AM
Thanks for the info. I will give it a try as soon as I can get my laptop to recognize the USB. I hate windows Vista. Heard a lot of people having problems with getting it to set the drivers right.
Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Saturday, June 09, 2012 2:27 PM
I know it's an old thread but I am now experiencing this high idle problem. it idles up to prevent it from stalling but then it wont back down.
I have a stock computer that Milzy Motors sports tuned for me. I've put a couple thousand miles on it and then all of sudden it started this high idle crap. it may even be getting worse. the funny thing is I too just changed my oil. I already swapped the IAC valve and no help. When I shut it off it seems to rest and idles normal until it senses a lower idle like when you start to stall out and then it goes into this high idle.



Any help would be appreciated.
Re: Megasquirt wont come out of high idle till restart at 160 degrees.
Sunday, June 10, 2012 4:24 AM
That's probably your problem. Letting Milzy program a PCM for you.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick
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