Idle Airflow: Why is it such a pain... (already searched and tested stuff...)
10-13-2004, 06:30 PM
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Idle Airflow: Why is it such a pain... (already searched and tested stuff...) I have been tinkering with my idle airflow lately, and quite frankly it is a PITA. I decided to try and adjust my airflow via the PCM and back off the set screw a little and pull my IAC counts up a little. Yeah, right. That didn't work. The "desired idle airflow", is that the amount of air the vehicle desires at idle? Or is it the amount of airflow the PCM wants to command the IAC valve to? Wouldn't this change based on engine vacuum? How does the PCM calculate "desired idle airflow" and the "IAC counts? YES, I already read all the threads about this.
No matter what I do, if I log "desired IAC counts" alone, they jump around, if I log the IAC counts AND "desires idle airflow", the "desired IAC counts" always reads in the 200s, regardless of idle, moving, etc. If I add to the idle airflow it does diddly. If I subtract from it all I get is stalling. If I adjust the set screw, my idle become nice and smooth with low IAC counts at idle (30s and below). Can somebody shed some light on how it actually works, and what changes to the idle airflow will do if you move them in either direction?
I am working on minor surging (depends on how I adjust the set screw more than anything), and the one thing I can't get rid of is bucking at almost no throttle coming off the line, or at low speeds. I can get rid of a lot with throttle cracker, but that does me no good for off idle. Do I need to adjust my threshholds? I have been messing with this stuff for awhile...help? Please?
No matter what I do, if I log "desired IAC counts" alone, they jump around, if I log the IAC counts AND "desires idle airflow", the "desired IAC counts" always reads in the 200s, regardless of idle, moving, etc. If I add to the idle airflow it does diddly. If I subtract from it all I get is stalling. If I adjust the set screw, my idle become nice and smooth with low IAC counts at idle (30s and below). Can somebody shed some light on how it actually works, and what changes to the idle airflow will do if you move them in either direction?
I am working on minor surging (depends on how I adjust the set screw more than anything), and the one thing I can't get rid of is bucking at almost no throttle coming off the line, or at low speeds. I can get rid of a lot with throttle cracker, but that does me no good for off idle. Do I need to adjust my threshholds? I have been messing with this stuff for awhile...help? Please?
10-14-2004, 04:55 PM
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ttt. I just posted this in HP Tuners forum. I can't believe nobody has thoughts on this. I am beginning to think it is a conspiracy like that whole lid throwing the MAF table off thing...
