QUICKSILVER2002
May 16th, 2005, 03:16 AM
Wondering if someone can help me here.
I have a c5 and have the tune dialed in pretty well (I have a pretty good handle on how most this stuff works), but the idle is still giving me fits.
It seems to not want to open the TB enough to hold a solid idle all the time. It is decent about 90% of the time, but then under just the right conditions it stumbles and almost dies. Those conditions seem to always include increased load (lights on, turning wheel....). And is more frequent as the throttle is just released, but sometimes happens in a steady state.
This never happens with the AC on, and I'm pretty sure this is because the desired airflow is much higher when it is on (TB is open a bit more with the IAC/ETC)
I have logged the condition several times and nothing really stands out as the problem except that the IAC desired airflow is just not high enough for the load.
My running airflow table is demanding about 9.5 g/sec, but the desired is only showing about 7.5 (maf and dyna-air is about 9.5 also). I'm pretty sure the idle trims are bringing the desired position down too much. It idles real strong (although a tad high) just after a flash and then it eventually drops the desired IAC airflow once the full idle learn takes place.
Like I said, with the AC on it idles like a rock (with the same RPM, but the desired airflow goes up to 9.5)
I've tried playing with the IAP table, but it did not seem to help (although I could have just done something wrong). I've also read quite a bit of info saying IAP has no impact once the motor is running (although this could be wrong, I know it has worked for some here, like what is stated in the sticky)
Anway, just wondering if anyone has any different ideas. I've tried just about everything. I wish I could log the idle trims (when is that going to be available?).
Also, what is a good timing value at idle. I’m wondering if I might have that too high, which is causing it to do a bad idle learn. I think I see about 19-20 adv at most idle conditions.
I have a c5 and have the tune dialed in pretty well (I have a pretty good handle on how most this stuff works), but the idle is still giving me fits.
It seems to not want to open the TB enough to hold a solid idle all the time. It is decent about 90% of the time, but then under just the right conditions it stumbles and almost dies. Those conditions seem to always include increased load (lights on, turning wheel....). And is more frequent as the throttle is just released, but sometimes happens in a steady state.
This never happens with the AC on, and I'm pretty sure this is because the desired airflow is much higher when it is on (TB is open a bit more with the IAC/ETC)
I have logged the condition several times and nothing really stands out as the problem except that the IAC desired airflow is just not high enough for the load.
My running airflow table is demanding about 9.5 g/sec, but the desired is only showing about 7.5 (maf and dyna-air is about 9.5 also). I'm pretty sure the idle trims are bringing the desired position down too much. It idles real strong (although a tad high) just after a flash and then it eventually drops the desired IAC airflow once the full idle learn takes place.
Like I said, with the AC on it idles like a rock (with the same RPM, but the desired airflow goes up to 9.5)
I've tried playing with the IAP table, but it did not seem to help (although I could have just done something wrong). I've also read quite a bit of info saying IAP has no impact once the motor is running (although this could be wrong, I know it has worked for some here, like what is stated in the sticky)
Anway, just wondering if anyone has any different ideas. I've tried just about everything. I wish I could log the idle trims (when is that going to be available?).
Also, what is a good timing value at idle. I’m wondering if I might have that too high, which is causing it to do a bad idle learn. I think I see about 19-20 adv at most idle conditions.