Idles too High

For discussing MicroSquirt (TM) configuration and tuning of fuel parameters (including idle valves, etc.).
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Blatzy
MegaSquirt Newbie
Posts: 11
Joined: Wed Jun 28, 2006 9:55 am

Idles too High

Post by Blatzy »

Help !!! My head ia about to burst.

I have read the tunning manual time and time again and still don't know satrt. I have installed a ms2 with a v3.0 running code 2.3 in GM 3.1 with 8lbs of boost. I can start and run the car but the idle is high and it is running rich. Where do I start? I am attempting to attach a datalog. Please HELP
Mike_Robert

Post by Mike_Robert »

You have excess air entering from somewhere, perhaps a gasket leak, a misadjusted idle screw, a split hose or a leaky brake booster diaphragm among many other potential sources. Please don't try to tune around this, you need to find out where the extra air is coming from. The richness almost certainly has nothing to do with the high idle. Also, most engines like to idle richer than stoich if that was your goal for an idle mixture.

-Mike
Bernard Fife
Super Squirter
Posts: 1009
Joined: Mon Feb 16, 2004 3:15 pm

Post by Bernard Fife »

Blatzy,

In addition to the vacuum leak potential sources Mike mentions, alo check your idle air controller (if you have one) to be sure it isn't open all the time.

If this is a GM stepper style IAC, and you aren't using MS-II to control it, then it may be in an intermediate position and allowing a lot of air to bypass, raising the idle. You can tape over the IAC port on the 'horn' of the throttle body to fix this - feel with your fingertip, you'll find it pretty quickly (or get the IAC working...)

Lance.
Blatzy
MegaSquirt Newbie
Posts: 11
Joined: Wed Jun 28, 2006 9:55 am

Post by Blatzy »

Taped over air horn brought Idle down to about 1200. Checked for leaks and couldn't find any. Apparently problem in IAC stepper This is a GM throttle body With GM IAC controlled by MSII. What now

Thank you
Blatzy
Bernard Fife
Super Squirter
Posts: 1009
Joined: Mon Feb 16, 2004 3:15 pm

Post by Bernard Fife »

Blatzy,

The next thing to do is to adjust the idle speed with the throttle stop screw. On GM TBs, it is often hidden behaind a cap (I drill a small hole in the cap and ue a sheet metal screw threaded into that hole to extract it).

Then you can use a screwdriver to turn the idle speed adjustment screw and fine tune the idle speed.

Lance.
Blatzy
MegaSquirt Newbie
Posts: 11
Joined: Wed Jun 28, 2006 9:55 am

Post by Blatzy »

I have turned the Idle adjustment screw alll the wat out car still idleing at 1250, but this is with the IAC horn unpluged. Should this be Plugged and what steps do I take on dialing in the IAC stepper.

thank you

Blatzy
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