Re: [DML] Re: idle yet again

[Soma576@xxxx]

In a message dated 11/15/03 3:00:33 PM Central Standard Time, 
doctorDHD@xxxx writes:

> My car, 6530, idles irregularly and at 900 - 1200 with both the idle 
> speed screw and the ECU screw out all the way. Am I screwed up?
> 
> Dave and 6530
> 

what is the idle speed screw? What is the ECU screw? are you referring to 
the primary idle speed screw (not used since there is electronic idle control on 
this car). the first screw (closest to the mixture unit) should be lightly 
closed. the other two are balancing screws for the left and right banks (also 
not used). you should close all three screws and then continue tuning. it 
might just be the problem, since you are not allowing the idle speed motor to 
fully regulate air flow at idle when the screws are open.

idle is electronically controlled and is not setable, per se. you can 
increase idle speed by changing the position of the throttle stop screw, but in a 
stock engine, it should be screwed down about 1/4 turn from the point where the 
throttle closes by itself w/o a stop screw. the stop screw keeps it from 
binding up or getting damaged. you should not be playing with this screw other 
than to set it at precisely that point. when it is screwed in too far (raise 
the idle), you are allowing air to get past the butterfly plates, again 
bypassing the idle speed motor and not allowing it to do its job properly. 

some discussion in recent weeks have pointed to a good use of the three brass 
idle screws to help smooth out the idle, but do not try this until EVERYTHING 
is 100% perfect. you don't want to introduce more variables while fixing a 
problem!

Andy


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