How to get IAC steps lower?
How to get IAC steps lower? This boggles me because I see high IAC counts when logging my car. I've already tried the throttle blade idea where you open it just before TPS senses 1% and that has helped none.
I really wish I understood what a high IAC count MEANS
I really wish I understood what a high IAC count MEANS
High IAC counts mean that the PCM is opening the IAC valve to supply the needed airflow for that idle condition. Stock vehicle usually see count around 40-70. It is not bad to have count in the lower 100s (like 125 or so) on cam'ed cars. What are you IAC counts at currently? Another method of lowering counts would be to enlarge the TB hole (some frown upon this, too large is reason for concern though), this allows more air to enter the engine and keeps the counts down for when you need a quick reacting or larger step count from the IAC valve. I wouldn't be to concerned about counts, so long as they are not above 180, you have plenty of room for idle correction. You need to remeber that the IAC valve works like the throttle blade and your foot ... it is constantly opening and closing to keep the idle from stalling or shooting up too high within it's range of 310 counts). Hope this helps. 
My IAC count when starting the car in the morning is 185 and stays there for around 30 seconds and then it slowly starts going down to 165 and then lower as the car warms.
My problem is that while it is in the 185-165 range, I have a terrible screeching noise coming from the intake which completely goes away at 165. I was hoping I could find a way to keep my IAC counts below 165 when starting so I can stop hearing that noise.
My problem is that while it is in the 185-165 range, I have a terrible screeching noise coming from the intake which completely goes away at 165. I was hoping I could find a way to keep my IAC counts below 165 when starting so I can stop hearing that noise.
You simply need to get more air into the engine with the throttle body closed to lower the counts. At least that's how I understand the concept...that extra air can come from cracking the blade a little bit (which you've already tried), or enlarging/adding another hole in the blade.
These don't sound abnormal to me, the PCM is commanding
higher startup air (like fast idle cam on a carb, w/ choke).
If you are at like 200, hot, that's bad because the IAC airflow
is not linear and you're nearing where more counts do not make
more air and the loop goes to hell.
Look at the IAC port and innards for "sharps" that will make it
dog-whistle. Maybe the IAC port snarfed up a flying chunk
and it's internally obstructed. A Torx screwdriver is all you
need, to check it out.
If you're using an epoxied ported TB, get that hole to at
least 3/8", makes a big difference.
higher startup air (like fast idle cam on a carb, w/ choke).
If you are at like 200, hot, that's bad because the IAC airflow
is not linear and you're nearing where more counts do not make
more air and the loop goes to hell.
Look at the IAC port and innards for "sharps" that will make it
dog-whistle. Maybe the IAC port snarfed up a flying chunk
and it's internally obstructed. A Torx screwdriver is all you
need, to check it out.
If you're using an epoxied ported TB, get that hole to at
least 3/8", makes a big difference.
My IAC count when starting the car in the morning is 185 and stays there for around 30 seconds and then it slowly starts going down to 165 and then lower as the car warms.
My problem is that while it is in the 185-165 range, I have a terrible screeching noise coming from the intake which completely goes away at 165. I was hoping I could find a way to keep my IAC counts below 165 when starting so I can stop hearing that noise.
My problem is that while it is in the 185-165 range, I have a terrible screeching noise coming from the intake which completely goes away at 165. I was hoping I could find a way to keep my IAC counts below 165 when starting so I can stop hearing that noise.
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Mine are 60-80 hot; but like everyone else starts out at 170 or so. I thought the idle experts say 60-80 is good for a cammed car?
You can also use the idle screw to adjust the numbers; just make sure when you are done that TPS still reads zero.
You can also use the idle screw to adjust the numbers; just make sure when you are done that TPS still reads zero.
These don't sound abnormal to me, the PCM is commanding
higher startup air (like fast idle cam on a carb, w/ choke).
If you are at like 200, hot, that's bad because the IAC airflow
is not linear and you're nearing where more counts do not make
more air and the loop goes to hell.
Look at the IAC port and innards for "sharps" that will make it
dog-whistle. Maybe the IAC port snarfed up a flying chunk
and it's internally obstructed. A Torx screwdriver is all you
need, to check it out.
If you're using an epoxied ported TB, get that hole to at
least 3/8", makes a big difference.
higher startup air (like fast idle cam on a carb, w/ choke).
If you are at like 200, hot, that's bad because the IAC airflow
is not linear and you're nearing where more counts do not make
more air and the loop goes to hell.
Look at the IAC port and innards for "sharps" that will make it
dog-whistle. Maybe the IAC port snarfed up a flying chunk
and it's internally obstructed. A Torx screwdriver is all you
need, to check it out.
If you're using an epoxied ported TB, get that hole to at
least 3/8", makes a big difference.
What do you guys think about me "smoothing" the edge of the IAC passage? Right now it's a 90 degree angle, what if I make the edge more of a curve instead of a sharp angle?
Try this procedure. Mine was at 170 when I started and I am at 60 now. No hole in TB.
1) Monitor your IAC, Idle Speed, throttle position voltage and your Throttle Position %.
2) With the key in the ON position, adjust your tb
set screw until your throttle position is 2%.
3) Turn your key to the OFF position.
4) Unplug your Throttle Position Sensor (TPS).
5) Turn your key to the ON position for a few
seconds, and then OFF again.
6) Plug in the TPS and then turn your key to
the ON position and restart logging. Your Throttle
Position will now be reset to 0 degrees and about .45-.55 volts.
7) Start your engine, if you are not at your desired IAC position redo the above procedures in smaller increments.
1) Monitor your IAC, Idle Speed, throttle position voltage and your Throttle Position %.
2) With the key in the ON position, adjust your tb
set screw until your throttle position is 2%.
3) Turn your key to the OFF position.
4) Unplug your Throttle Position Sensor (TPS).
5) Turn your key to the ON position for a few
seconds, and then OFF again.
6) Plug in the TPS and then turn your key to
the ON position and restart logging. Your Throttle
Position will now be reset to 0 degrees and about .45-.55 volts.
7) Start your engine, if you are not at your desired IAC position redo the above procedures in smaller increments.
Try this procedure. Mine was at 170 when I started and I am at 60 now. No hole in TB.
1) Monitor your IAC, Idle Speed, throttle position voltage and your Throttle Position %.
2) With the key in the ON position, adjust your tb
set screw until your throttle position is 2%.
3) Turn your key to the OFF position.
4) Unplug your Throttle Position Sensor (TPS).
5) Turn your key to the ON position for a few
seconds, and then OFF again.
6) Plug in the TPS and then turn your key to
the ON position and restart logging. Your Throttle
Position will now be reset to 0 degrees and about .45-.55 volts.
7) Start your engine, if you are not at your desired IAC position redo the above procedures in smaller increments.
1) Monitor your IAC, Idle Speed, throttle position voltage and your Throttle Position %.
2) With the key in the ON position, adjust your tb
set screw until your throttle position is 2%.
3) Turn your key to the OFF position.
4) Unplug your Throttle Position Sensor (TPS).
5) Turn your key to the ON position for a few
seconds, and then OFF again.
6) Plug in the TPS and then turn your key to
the ON position and restart logging. Your Throttle
Position will now be reset to 0 degrees and about .45-.55 volts.
7) Start your engine, if you are not at your desired IAC position redo the above procedures in smaller increments.
