Idle tuning w/ quick blip of throttle in park

Hey guys! Been a while since I have done some idle tuning. I have the idle pretty good (IAC's could come down a little further but its ok for now i think).

I forget what the proper procedure is for the ls1 (2000 pcm) for fixing quick throttle blips. I thought it was the throttle follower tables. There have been too many hands on this table in the past so it is most likely the issue.

What values should I be watching and how to adjust based on the values in the appropriate tables?

I think IAC, MAP, and Advance at first but maybe there is a better set of data I should be using.

I attached the bin, scan log and config.

Thanks in advance all!

I tried playing with RAF a bit tonight and I was wondering what makes the decision for the Idle Desired Airflow value?

I noticed that its reading at about 4-6 g/sec at idle p/n. Of course my table is way off because the tuning school suggested 13-17 g/sec for larger cams. This of course makes the idle adapt stit way negative.

With RTT I was able to adjust he values down to 5 to see what would happen. My IACs dropped to about 20 and my idle stit was about -.7 and idle behavior seemed to be the same.

So I blipped the throttle and still the same problem.

All the other search results on this said if you have a surge its because of too much fuel. Now, those were relating to oscillating idle where the pedal isn't being pressed in.

At the blip my wideband is reading 13.44 and my o2's are showing 40's so yes it is a little rich after the blip. I wouldn't think this would be too rich though.

Thoughts?

If you are talking about like a little bog when you try to rev it real fast, making idle closed throttle timing values 0-1200 rpm 0-.28gs the same in all your timing tables so there isnt a huge difference when it changes from one table to the other helped me out a lot.

If I give it a quick tap (about 8% TPS) to about 2500 rpm, it dies. That is a good suggestion because when it gets up to 2500 im seeing 39 advance. I wish there was a way to see what tables it is pulling timing from in the logging :(

You can just log all the different timming parameters to see whats been added/subtracted to generate the overall advance.

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Originally Posted by wokaz

You can just log all the different timming parameters to see whats been added/subtracted to generate the overall advance.

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How do you do that? :o

One way I found (my pcm os version of course) is that if i set the idle overspeed and underspeed spark tables to 0, the advance didn't change at idle.

But I did get some crazy oscillation though :)

So with the topic at hand, I adjusted my throttle follower table to increase the iac count. That kept it running but I got into an oscillation problem that eventually calms down. Spikes about 4-5 times both directions before it settles out.

I think that I will need to resolve that oscillation problem with the spark overspeed underspeed but not sure exactly the method to doing so.

My cam is so drastically different from stock that I don't know where to begin, besides blindly adding 2 and -2 appropriately until I get a somewhat tame result.

Any thoughts on that?

Why are you're STIT's taking more air out than the engine desires at idle? Is this the car in your sig?

Did you tune your VE and MAF first?

You need to make your High/Low Octane Spark tables be much closer to your Idle Spark Advance tables.

You need to log Idle Advance too in your config.

Your cam is roughly the size of mine. Your throttle body and intake are larger though. Have you played with the set screw on the throttle body blade? Someone had drilled my hole larger on my butterfly and I ended up have to close it all the way to get the IAC near where it should be. I wonder if your's is opened a little too much? I don't know what injectors you have but, here is my tune so far. I'm still tweaking it but it's getting close. Maybe it can be a reference point for you.

Once this car is warmed up it drives pretty damn good.

Your throttle follower is the airflow adder when you're sitting still and blip the throttle. The exact scenario you're describing. Log it and see how much it's adding, and how fast it is decaying. By your settings, it should be decaying very slowly. Might wanna add some air to it and/or add to the delay. It's set to zero, maybe set it to 1 second.

But again, as you noticed when you did your search, fueling plays a big part in not only idle quality (surging) but return to idle too. You VE doesn't look right at all. You still have your long term fuel trims on, nd they could be contributing to a rich condition. Don't know unless you scan it.

Quote:

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Originally Posted by edcmat-l1

Your throttle follower is the airflow adder when you're sitting still and blip the throttle. The exact scenario you're describing. Log it and see how much it's adding, and how fast it is decaying. By your settings, it should be decaying very slowly. Might wanna add some air to it and/or add to the delay. It's set to zero, maybe set it to 1 second.

But again, as you noticed when you did your search, fueling plays a big part in not only idle quality (surging) but return to idle too. You VE doesn't look right at all. You still have your long term fuel trims on, nd they could be contributing to a rich condition. Don't know unless you scan it.

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I have tuned my VE and smoothed it out several times. Would you mind pointing out which part of my VE doesn't look right? I tried both methods of tuning part throttle VE with narrowbands then went to my wideband to see if there was a huge difference and I was seeing at most 2% between them.

Thanks very much in advance!

Quote:

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Originally Posted by 99LS1SS

Why are you're STIT's taking more air out than the engine desires at idle? Is this the car in your sig?

Did you tune your VE and MAF first?

You need to make your High/Low Octane Spark tables be much closer to your Idle Spark Advance tables.

You need to log Idle Advance too in your config.

Your cam is roughly the size of mine. Your throttle body and intake are larger though. Have you played with the set screw on the throttle body blade? Someone had drilled my hole larger on my butterfly and I ended up have to close it all the way to get the IAC near where it should be. I wonder if your's is opened a little too much? I don't know what injectors you have but, here is my tune so far. I'm still tweaking it but it's getting close. Maybe it can be a reference point for you.

Once this car is warmed up it drives pretty damn good.

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Thanks for the reference file! I performed the unplugged IAC method to get the throttle blade in the correct idle position at running temp.

Quote:

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Originally Posted by edcmat-l1

Your throttle follower is the airflow adder when you're sitting still and blip the throttle. The exact scenario you're describing. Log it and see how much it's adding, and how fast it is decaying. By your settings, it should be decaying very slowly. Might wanna add some air to it and/or add to the delay. It's set to zero, maybe set it to 1 second.

But again, as you noticed when you did your search, fueling plays a big part in not only idle quality (surging) but return to idle too. You VE doesn't look right at all. You still have your long term fuel trims on, nd they could be contributing to a rich condition. Don't know unless you scan it.

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Forgot to ask this, what ve tuning method do you find the best results with? The tuning school method is to use ltft average with maf disabled. Which you reset fuel trims after each scan and flash. Part throttle tuning of course, with PE disabled.
Thanks for the feedback I really appreciate it!

For those wondering I ended up finding Rinkrat456's post to help out with my idle problem.
http://www.hptuners.com/forum/showthread.php?t=36318

I tried doing the normal VE tuning method to get idle and part throttle in place but with the xer281hr cam and SLP LT headers, the readings were going positive to negative all the time.

This method has worked out very well so far. I can get it to idle with no under or overspeed settings with a static 22 degrees. I had to remove alot of fuel in the VE table in the idle areas to be able to use VCM controls effectively. This was due to my ltft and wideband methods generally reading wrong and causing me to add too much fuel.

When I started to get that lovely and awesome chop chop sound I knew I had finally found a good area.

I am not done yet but this is getting me much closer to where I should be.

BTW this cam seems to like 1000 rpm for idle. You can easily bring it down to 800 but I personally liked the sound at 1k rpm.

Here is a link to the video so you can hear what I am saying :)

http://www.youtube.com/watch?v=BHMAuCAHBt0

Playing with it some more I found real quick throttle response with 28 degrees and a little richer setup. Seems to idle pretty decently too.

Anyone have ideas on that? Should Idle in park be really efficient or responsive? Aside of course from pleasure of sound :)