Problem with pushing in clutch/ idle with AC on...
09-03-2013, 05:12 PM
#1
Problem with pushing in clutch/ idle with AC on... A little back story here. I recently swapped heads on my 04 gto and have been in the process of redoing the idle. Mods are as follows.
229/234 .612/.600 111+4 cam
Trick flow 220's hand ported
Fast 92/92 combo runners ported to match heads
Kooks 1 3/4" headers with catless mids
OTRCAI
SD tune
I have been slowly dialing in my RAF and everything else. The car idles at 800 rpm with an IAC of 60 ish. I do reset the IAC and TPS whenever I mess with the idle screw. I had an issue with the bottom of the idle screw having a burr and hanging up on the stop on the tb itself. I recently took the tb off and smoothed this out.
Here is my problem. With the car running at any given speed I can push the clutch in without the AC on and everything is fine. I can free rev with the car at a stop without the AC on and it is fine. But if I turn the AC on the car always wants to stall out or die. Also when parked without the ac on the STIT stays close to zero. With the AC on it always wants to add here.
I am logging an Idle AC Airflow parameter and it always adds 1.5 ish at idle. I think if I could find out where to adjust this at I could solve the problems but so far I have not found it.
At this point I am tired of blindly changing things to see if they help or hurt so I am asking for help.
Attached is my config file, my tune, and a log. The log shows me driving with the AC on and pressing the clutch in. You can see the rpm's drop way down. I then turn the AC off and repeat the same thing and the car just drops to idle and holds it. I then do the same thing again one more time.
Any feedback or advice would be great. I will attempt anything at this point.
229/234 .612/.600 111+4 cam
Trick flow 220's hand ported
Fast 92/92 combo runners ported to match heads
Kooks 1 3/4" headers with catless mids
OTRCAI
SD tune
I have been slowly dialing in my RAF and everything else. The car idles at 800 rpm with an IAC of 60 ish. I do reset the IAC and TPS whenever I mess with the idle screw. I had an issue with the bottom of the idle screw having a burr and hanging up on the stop on the tb itself. I recently took the tb off and smoothed this out.
Here is my problem. With the car running at any given speed I can push the clutch in without the AC on and everything is fine. I can free rev with the car at a stop without the AC on and it is fine. But if I turn the AC on the car always wants to stall out or die. Also when parked without the ac on the STIT stays close to zero. With the AC on it always wants to add here.
I am logging an Idle AC Airflow parameter and it always adds 1.5 ish at idle. I think if I could find out where to adjust this at I could solve the problems but so far I have not found it.
At this point I am tired of blindly changing things to see if they help or hurt so I am asking for help.
Attached is my config file, my tune, and a log. The log shows me driving with the AC on and pressing the clutch in. You can see the rpm's drop way down. I then turn the AC off and repeat the same thing and the car just drops to idle and holds it. I then do the same thing again one more time.
Any feedback or advice would be great. I will attempt anything at this point.
09-04-2013, 05:52 PM
#2
Well for the time being I just lowered my IAC counts down from 60ish to 40ish. This gives me more air all over. It is just a bandaid for the time being and I would still like to hear some other opinions on this.
I think it is just the design of the fast92 tb that makes things behave like this.
I think it is just the design of the fast92 tb that makes things behave like this.
09-04-2013, 10:21 PM
#3
I noticed you try to keep the same rpm for your Target Idle speed vs coolant temp. With the a/c on, you have an extra load on there. I noticed with my tr224 with 112lsa, trying to keep 800 rpm idle was fairly difficult. If you are to keep the same rpm at the same temp, you will have to rely on other tables to compensate for the load. If it is stalling, those other tables are not accounting for the extra load and not providing the air necessary to offset the new load.
Areas to play with:
-Adaptive idle airflow
Idle Proportional Airflow High/ingear/acon
Idle Proportional Airflow low/ingear/acon
-Base running airflow
Idle airflow vs coolant temp (this will affect idle open loop as well) ie the first 30 seconds prior to closed loop if hot, hot starts with a/c on etc
Also keep in mind that as you come to a stop, the adaptive airflow switches off. If your open loop values aren't up to par, this usually leads to a stall with the a/c on.
With my MAF and SD dialed in, my only issue was the hot start with a/c on and playing with the Idle airflow vs coolant temp kept the car from stalling out if the a/c was on. It also had the effect of giving me a "hanging" rpm coming to a stop which keeps the car from stalling. ie 1000 rpm then once stopped back to 850. Prior to increasing that table, I had the effect of 600-800 rpm ie felt like it was going to stall whenever I came to a stop sign.
Areas to play with:
-Adaptive idle airflow
Idle Proportional Airflow High/ingear/acon
Idle Proportional Airflow low/ingear/acon
-Base running airflow
Idle airflow vs coolant temp (this will affect idle open loop as well) ie the first 30 seconds prior to closed loop if hot, hot starts with a/c on etc
Also keep in mind that as you come to a stop, the adaptive airflow switches off. If your open loop values aren't up to par, this usually leads to a stall with the a/c on.
With my MAF and SD dialed in, my only issue was the hot start with a/c on and playing with the Idle airflow vs coolant temp kept the car from stalling out if the a/c was on. It also had the effect of giving me a "hanging" rpm coming to a stop which keeps the car from stalling. ie 1000 rpm then once stopped back to 850. Prior to increasing that table, I had the effect of 600-800 rpm ie felt like it was going to stall whenever I came to a stop sign.
