You are correct, you now understand the theroy just fine.
Also, I just looked at the 89 chip data (Both USA and EURO chips) and you are 100% correct, the idle is set to 880RPM. So for your car I'd set the base to 900RPM (but setting to 880 is just fine also, the spec says +/- 20RPM from the DME setting) and then pull the jumper out. The ICV should then pull the idle down to 880RPM.
Are you running the stock chip? If not you really need to find out what the idle value is set to in the custom chip and the only way to do that is to talk to the supplier or have someone read the data off the custom chip.
Now if your idle drops to values much lower than the 880 you have an issue else where. Air leaks in the intake are common but these ussually tend to pull the idle up not down unless the leak is large. You can test for air leaks easily with simple starter fluid, run the car at idle and spray the fluid near the intake tubes where they connect to the heads. If you have leak at one of those rubber gaskets (they often get sucked in) it will draw the fuild in and introduce false fuel and the idle with surge up. Start by looking for the air leaks. One other source is a faulty oil cap, if you pull the oil cap off with the car at idle the idle should go up because of extra (un-metered air) introduced into the system. If you pull the cap off and nothing happens this is a red-flag that something is wrong. I suggest you start looking for air leaks first if the idle procedure does not work.
After this we can discuss CO settings but it makes no sence to even look at CO untill you are certain you have no air leaks.
And of course a faulty ICV could cause your issue as well so please test it as I mentioned in my thread.
Quote:
Originally Posted by hcoles
Sal, I think this is sinking in for me... setting the ICV at center and the "idle screw" turned to get the rpm's at the target idle rpm (I think for me it is 880, I have an 89) when this is done the "system" now has proper head room to let the DME control the idle. Right?
Yes, if you have the time/etc. post a how to get a close adjustment for the CO.
I have a variable power supply at work so I'll try the variable method... hopefully I can see if the valve movement has "glitches" indicating bad spots. My valve is almost 20 years old now... so likely has some worn spots on the reostadt... if that's what's in there.
thanks.
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