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start-up/idle issues...imagine that?

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Old Aug 19, 2008 | 02:27 PM
  #11  
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Originally Posted by Superado
I'll look at those...thanks!

As of yesterday...I have a hesitation @ WOT...meaning...
when I mash the pedal to the floor...instead of it going WOT, it hesitates for a couple seconds...then goes WOT...
This has never happened before...where should I look?
You have a log of it doing that?
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Old Aug 19, 2008 | 02:40 PM
  #12  
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no...I hope to log it this afternoon...
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Old Aug 20, 2008 | 08:01 AM
  #13  
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The idle issue's you are having are the idle timing ,high/low octain tables ,VE and startup air tables.Get those figured out and the truck will have no problems on startup/idle area's.

Last edited by BlownChevy; Sep 29, 2008 at 02:29 PM. Reason: QUIT POSTING YOUR SIG, YOU KNOW BETTER.
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Old Aug 20, 2008 | 08:50 AM
  #14  
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Originally Posted by Superado
no...I hope to log it this afternoon...
logged on the way into 2nd job last night...and of course...didn't do it!
maybe it was a fluke, but it did it 2 or 3 times Monday...

thanks guys for the input on the start-up/idle issues...much appreciated!

Last edited by Superado; Aug 21, 2008 at 05:31 PM.
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Old Aug 21, 2008 | 05:29 PM
  #15  
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made the following changes this afternoon...found on efilive forum...so far...so good

Increased the Startup Friction Airflow Correction table for better starts. Although this doesn't really have to do with idle swing, I thought I'd include it because it seems to be a common problem. I increased this table by 4 grams/second across the board. Now, my warm start issues are gone. It was stumbling right after startup, barely running because there wasn't enough initial airflow. Adding air in here is a good, temporary way to add in the airflow, which will be decayed out after the first 30 seconds or so.
Changed the Learned Airflow Correction table by zeroing out the 0-20 absolute rpm cells. This means the car won't correct the learned airflow values (STITs/LTITs) until it's more than 20 rpms above/below desired idle speeds. With cam'd cars that have a choppier idle, the STIT/LTIT settings can be too aggressive. This softens them up a little.
Changed the Direct Airflow Correction table for High and Low RPM scenarios (Drive, A/C on, etc.). IMO, this was also making very aggressive airflow corrections. By zeroing out the 0-40rpm cells and reducing the remaining cells, I was able to prevent the idle from over-correcting and swinging up & down.
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