Terrible Lean at Idle with AC-on
Sorry to hijack, but I have a similar issue. With my AC off & the car sitting for 2 hours, the IAC count was 175 when I started the car, I have seen 200+ on complete cold start ups, with the AC on & off. Where should the count be, after the car is at normal opporating temps?
My car does not idle great all the time, especially when it is cooler.
I had my car retuned earlier this spring for a bigger stall & asked for some help with cold starts...I'm looking some ideas before I do anything else with it.
The throttle body hole is stock, I have H/C & u/d pulley, stalled A4.
Thanks for any advice!
My car does not idle great all the time, especially when it is cooler.
I had my car retuned earlier this spring for a bigger stall & asked for some help with cold starts...I'm looking some ideas before I do anything else with it.
The throttle body hole is stock, I have H/C & u/d pulley, stalled A4.
Thanks for any advice!
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Well, i finally figured it out, I just had to crank up the VE table at idle with AC-on. The TPS vs. RPM map in the custom operating system makes things SO much easier =D
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uhhh well I thought you had already been through the VE table. I thought this post was because of a lean condition that VE tuning wouldn't/didn't fix...
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Sorry to hijack, but I have a similar issue. With my AC off & the car sitting for 2 hours, the IAC count was 175 when I started the car, I have seen 200+ on complete cold start ups, with the AC on & off. Where should the count be, after the car is at normal opporating temps?
My car does not idle great all the time, especially when it is cooler.
I had my car retuned earlier this spring for a bigger stall & asked for some help with cold starts...I'm looking some ideas before I do anything else with it.
The throttle body hole is stock, I have H/C & u/d pulley, stalled A4.
Thanks for any advice!
My car does not idle great all the time, especially when it is cooler.
I had my car retuned earlier this spring for a bigger stall & asked for some help with cold starts...I'm looking some ideas before I do anything else with it.
The throttle body hole is stock, I have H/C & u/d pulley, stalled A4.
Thanks for any advice!
So, to clarify, when you start up, your IAC counts are around 175-200 and they stay there even after 2 hours? And your car wants to stall and die when coming to a stop or letting out the clutch? Anything else?
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My VE table was already set before I started messing with the AC, even the cell where the AC idle was set. I didn't understand why the IAC counts were flying over 200 at idle when I flipped the AC on and leaning out the VE parameters that I had already worked through. Well, I finally realized that if you zero out all of your tables, then it will kick the IAC valve to over 200 counts, i put the tables back and added a little more fuel via the TPSvRPM VE table (although if I were to hit that cell with the AC-off, it will be a little too rich). It had to be a balance between it all to get it to work well. I'm still tweaking it slightly, but at least I can use the ac city driving now =D
It sounds like your tuner did not modify the RAFIG table. Also, if the IAC is 175 after at hot idle, then that means you need to make your throttle hole just a weee bit larger so your IAC counts will come back down. BUT first, what is your idle set at? Depending on where the idle is set, your counts should be between 20-75 or so. 175 seems a bit high if that is where it is at when you're at hot idle. If it is 175 or even 200+ when you first start up, it is possible that when you asked your tuner to adjust for cold start-ups, that he/she increased your Startup Airflow Correction or Startup Friction airflow corrections to compensate, but its suppose to decay after startup.
So, to clarify, when you start up, your IAC counts are around 175-200 and they stay there even after 2 hours? And your car wants to stall and die when coming to a stop or letting out the clutch? Anything else?
So, to clarify, when you start up, your IAC counts are around 175-200 and they stay there even after 2 hours? And your car wants to stall and die when coming to a stop or letting out the clutch? Anything else?
I just went out & started it, it has been sitting for over 5 hours. IAC count was 177 when I started it, idle was about 1150. Within 2 minutes the IAC was under 100 & the RPMs were under 1000. After 4 minutes, coolant temp was 165, IAC count was in the high 60s, low 70s, the car was idling between 850 & 940.
Do you think adjusting the idle screw on the TB would help it?
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My bad, the 2 hours I was talking about was cool down time. After the engine is at normal operating temps, the IAC counts are under 100. After the initial start up/warm up the idle and drivablility is good.
I just went out & started it, it has been sitting for over 5 hours. IAC count was 177 when I started it, idle was about 1150. Within 2 minutes the IAC was under 100 & the RPMs were under 1000. After 4 minutes, coolant temp was 165, IAC count was in the high 60s, low 70s, the car was idling between 850 & 940.
Do you think adjusting the idle screw on the TB would help it?
I just went out & started it, it has been sitting for over 5 hours. IAC count was 177 when I started it, idle was about 1150. Within 2 minutes the IAC was under 100 & the RPMs were under 1000. After 4 minutes, coolant temp was 165, IAC count was in the high 60s, low 70s, the car was idling between 850 & 940.
Do you think adjusting the idle screw on the TB would help it?
Haans249,
I'm glad you fixed your issues. I'm having both of these problems as well in OLSD, and I'm still on the stock OS (not willing to custom OS yet...). I tried messing with the AC idle tables, but couldn't see any improvement either. Like you, I alleviated the idle lean AC-on issue by increasing the idle VE cells in the kPa range 50-60. Since my car normally idles in the 30-35 range this worked out fine.
The lean cold start issue was cured with Commanded Fuel in Open Loop by wildly decreasing the values below 80 C. Was there a better way to solve this problem? I don't like to see commanded 10.5 - actual 13.1 !!
Thanks,
Dan
I'm glad you fixed your issues. I'm having both of these problems as well in OLSD, and I'm still on the stock OS (not willing to custom OS yet...). I tried messing with the AC idle tables, but couldn't see any improvement either. Like you, I alleviated the idle lean AC-on issue by increasing the idle VE cells in the kPa range 50-60. Since my car normally idles in the 30-35 range this worked out fine.
The lean cold start issue was cured with Commanded Fuel in Open Loop by wildly decreasing the values below 80 C. Was there a better way to solve this problem? I don't like to see commanded 10.5 - actual 13.1 !!
Thanks,
Dan
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Hey Dan,
That is good to hear. I still haven't figured out why it cranks the IAC valve open so much, its just like if I were to set the AC-on Idle to the same as my regular idle it would still pop the IAC valve open a ton. My engine compensation airflow is set to like .3 at the highest, so that is not affecting it, and all the tables seem to not affect it either. It seems like there is another table somewhere that causes the IAC valve to open up upon ac-on.
The lean cold start up issue is just the nature of the beast. You should really update to the COSv5 operating system, it is really something else, and is super bad ***!
That is good to hear. I still haven't figured out why it cranks the IAC valve open so much, its just like if I were to set the AC-on Idle to the same as my regular idle it would still pop the IAC valve open a ton. My engine compensation airflow is set to like .3 at the highest, so that is not affecting it, and all the tables seem to not affect it either. It seems like there is another table somewhere that causes the IAC valve to open up upon ac-on.
The lean cold start up issue is just the nature of the beast. You should really update to the COSv5 operating system, it is really something else, and is super bad ***!
Honestly, you're not making much sense, and I don't really understand where the problem is. You said before that you had cold idle issues. I think what you're talking about is when you start the car that the idle hangs high until it comes up to temp. Is that correct? If so, the tuner may have just bumped the Desired Idle table until your motor come to temp to help with the cold start issue you were talking about. Am I missing anything? Do you have any other problems with driveability issues with it stalling coming to a light etc? Don't mess with the idle screw, if you bump it too high the TPS will register voltage and will mess up your idle tables.
silly question, but what RPM is being commanded at idle for AC-ON? Is it higher? There are some other tq compensation tables for accessory loading, check those out as well to be thorough.
If the IAC jacking is found to be the culprit, which it almost certainly must be, the changes Bink outlined will further exaggerate your condition. If this is the only issue you have left, why not just move back to closed loop? Just re-enable STFTs, leave the LTs off.
If the IAC jacking is found to be the culprit, which it almost certainly must be, the changes Bink outlined will further exaggerate your condition. If this is the only issue you have left, why not just move back to closed loop? Just re-enable STFTs, leave the LTs off.
Why do you enable the stft s and leave the ltfts off?
Why does turning putting the system back into closed loop solve the problem?
I was haveing the same problem as the guy that started this thread. I put the car back in CL and it stays running.
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The reason why is because there is no automatic adjustment for fueling. When you flip the AC on, there is more load on the motor, and from the parameters in the tune, it will command more air (higher IAC valve positions) to try and hold idle...but, if you're in a OLSD tune, then there is no fuel being added to that air, and you get a bad lean condition, which will cause your stalling issue. For my setup, i just upped the AC-on idle cell of the VEtable and it fixed my problem.
