Results 1 to 6 of 6

Thread: idle adjustments and airflow

  1. #1
    Junior Member
    Join Date
    Feb 2006
    Posts
    42

    Default idle adjustments and airflow

    Newbie. Installed air box, intake, mild cam, heads, headers, exhaust.
    Remaining stock is the TB and MAF. CATS have been removed.
    I am using EFILive FlashScan V7.
    I have read thru a PCM tuning doc I found on LS1racer.com.
    I have got a bit of idle surging.
    Adjusted TB set screw. Unplugged TP sensor to reset it.

    IACDES_B (desired idle air control air flow) was significantly less than DYNAIR (dynamic air flow) So...
    Adjusted IAC effective area table to the right. Which definately helped idle.

    Idle surging is nearly all gone but other issues appear to have been created.

    LTFTs are positive approx. +4.
    Warm idle AFR is often going into 15s.
    WOT AFR is at 13.5

    Before TB set screw adjustment I had lots of idle surging. But.
    LTFTs are slightly negative or 0
    Warm idle AFR was in the 14s.
    WOT AFR is at 12.5

    Questions:
    1. PCM doc mentioned lowering base proportional. Where is that at in EFILive?

    2. PCM doc mentioned adjusting running airflow. Where is that at in EFILive?

    3. How do I fix the positive LTFTs. By adjusting the MAF table?

    4. PCM doc mentioned adjusting adaptive idle limits and/or air flow. Where is that at in EFILive?

    5. PCM doc mentioned adjusting idle airflow. Where is that at in EFILive?

    6. Is there any other table I need to tweek to fix the issues that have poped up?

  2. #2
    Unknown Zone TAQuickness's Avatar
    Join Date
    Jan 2005
    Posts
    2,940

    Default

    Quote Originally Posted by heavyfoot
    Questions:
    1. PCM doc mentioned lowering base proportional. Where is that at in EFILive?
    I don't know

    Quote Originally Posted by heavyfoot
    2. PCM doc mentioned adjusting running airflow. Where is that at in EFILive?
    B4307

    Quote Originally Posted by heavyfoot
    3. How do I fix the positive LTFTs. By adjusting the MAF table?
    by returning your IACEA to stock, using the AutoVE tutorial to adjust your VE and or MAF, then adjusting your B4307

    Quote Originally Posted by heavyfoot
    4. PCM doc mentioned adjusting adaptive idle limits and/or air flow. Where is that at in EFILive?
    I don't know, but you shouldn't need to if you complete #3

    Quote Originally Posted by heavyfoot
    5. PCM doc mentioned adjusting idle airflow. Where is that at in EFILive?
    Return the set screw back to stock


    Quote Originally Posted by heavyfoot
    6. Is there any other table I need to tweek to fix the issues that have poped up?
    In some cases, adjustments to the throttle cracker/follower may be necessary.

    I wouldn't worry about desired vs actual airflows too much. But you should pay attention to the IAC step counts. Stock is in the 60-65 ish range at hot idle. You do not want to go lower than these values. I run mine in the 90-110 range.

  3. #3
    Junior Member
    Join Date
    Feb 2006
    Posts
    42

    Default

    oK...are you saying all idle problem can be resolved by recalibrating the VE tables? I guess I'm a bit confused. There is tons of documentation out there suggesting, drilling TB, adjusting TB screw, tweaking VE, tweaking spark, etc. or were you just giving me a starting point?

  4. #4
    Lifetime Member
    Join Date
    Jul 2005
    Posts
    702

    Default

    VE is crucial to EVERY SINGLE fueling calculation. without it, all other tweaks are kinda worthless. start with VE, once that settles, you can actually start looking elsewhere and see what needs to be adjusted.
    of course there's always my old writeup:
    http://redhardsupra.blogspot.com/200...le-tuning.html
    but this isn't exactly for a newbie. might point you in the right direction tho.

  5. #5
    Unknown Zone TAQuickness's Avatar
    Join Date
    Jan 2005
    Posts
    2,940

    Default

    Quote Originally Posted by heavyfoot
    oK...are you saying all idle problem can be resolved by recalibrating the VE tables? I guess I'm a bit confused. There is tons of documentation out there suggesting, drilling TB, adjusting TB screw, tweaking VE, tweaking spark, etc. or were you just giving me a starting point?
    No. As RHS stated, VE is the back-bone to a proper tune. When the VE is dialed in (for the idle cells) you can then dial in the desired aire flow (b4307). VE and B4307 share an equal role in idle quality.

  6. #6
    Junior Member
    Join Date
    Feb 2006
    Posts
    42

    Default

    Ok...thx for the replies. Ill get started.

Similar Threads

  1. E38 idle airflow
    By KenB in forum E37, E38 & E67 PFI ECM's
    Replies: 11
    Last Post: May 28th, 2012, 11:20 PM
  2. idle tuning & airflow
    By ZL1Killa in forum Gen III V8 Specific
    Replies: 8
    Last Post: October 14th, 2009, 07:47 AM
  3. Minimum Idle Airflow Tables
    By fperra in forum Gen IV V8 Specific
    Replies: 2
    Last Post: August 28th, 2009, 01:50 AM
  4. Desired Idle Speed and Idle Airflow
    By Bowtieman in forum General (Petrol, Gas, Ethanol)
    Replies: 1
    Last Post: March 20th, 2006, 10:07 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •