Results 1 to 6 of 6

Thread: IAC Desired 0 Cold - Jumps 310 desired IAC around 55C and Idles

  1. #1
    Tuner in Training
    Join Date
    Apr 2012
    Posts
    16

    IAC Desired 0 Cold - Jumps 310 desired IAC around 55C and Idles

    I am working on a swapped 87 Blazer it has an 0411 PCM in it and everything is running great except cold starts.

    When I cold start the car the IAC desired and actual read 0 and you have to use your foot to keep the car alive. Once the car hits about 55C or 130F IAC desired jumps to 310 and the engine idles up to 1500 rpm and then slowly decreases down to desired idle. Once it is fully warm IAC is around 40-60 at 212F.

    I have the default IAC position set to 210 and had it to 310 a while back to try and see if maybe the logger just wasn't reading the desired IAC. The weird thing is is that it still defaults to 310. Any time you start it above 130F the car will immediately jump the desired IAC up like normal and step it down but I tried flashing it back to 210 and it still goes to 310.

    I have done a few days of cold starts and no matter what below 130F desired IAC is 0.

    Have any of you experienced this?

    I am guessing it is the pcm but not sure. There are 0 codes and 0 air leaks. I have checked headers, intake and tb for leaks.

  2. #2
    Senior Tuner mowton's Avatar
    Join Date
    Mar 2007
    Location
    Florida
    Posts
    3,773
    With nothing to look at, make sure System>Vehicles>System Options, the appropriate platform doesn't have ETC=1

    Also make sure your TPS(v) is below .800 volts.

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

    ERM Performance Tuning -- Interactive Learning ..from tuning software training to custom tunes
    HP Tuners Dealer- VCM Suite (free 2hr training session with purchase), credits and new Version 2.0 turtorial available
    http://www.ermperformancetuning.com
    http://www.facebook.com/ERMPerformanceTuning

    [email protected]

  3. #3
    Tuner in Training
    Join Date
    Apr 2012
    Posts
    16
    It isn't above .8V but I will check. I can open the throttle more and do a TPS reset and it still learns idle as long as it is above 55C.
    Attached Files Attached Files

  4. #4
    Tuner in Training
    Join Date
    Apr 2012
    Posts
    16
    I guess to add a little more info. The car sometimes learns a bank +/- 10% out on fueling at a given airflow and then reels it back in later in the drive to where the LTM's are within +/- 2%. I went through and found two header leaks and thought I cleared it up because the LTM's settled in within +/- 5% of eachother and the car smelled great. It wasn't running rich. Then all the sudden a few days later, it starts acting up again and you can smell it is running rich but this time the opposite bank learns out a bunch of fuel. Yet later in the drive that bank cleared up in the same conditions and fell back to around 1 percent correction in the exact same cell it learned the 10% correction in previously. Park the car and it is idling, all the sudden it starts pulling fuel again and smells rich, but only on a single bank again.

    Things that have been tried: switching o2's and it does not follow them, sprayed the intake with ether and no change in idle or STM's or LTM's and have gone back through the exhaust to check it was sealing. The last thing is switching injectors from bank to bank, but like I said it's switched from one bank pulling fuel one day to the next another day, to no banks pulling fuel and it saying everything is right another day/time during the day. Have also checked fuel pressure with a gauge during driving to make sure it was correct also.

  5. #5
    Senior Tuner mowton's Avatar
    Join Date
    Mar 2007
    Location
    Florida
    Posts
    3,773
    Quote Originally Posted by radcannon View Post
    It isn't above .8V but I will check. I can open the throttle more and do a TPS reset and it still learns idle as long as it is above 55C.
    File is Tuner locked...Make sure to clear Master/Slave in Tune Details

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

    ERM Performance Tuning -- Interactive Learning ..from tuning software training to custom tunes
    HP Tuners Dealer- VCM Suite (free 2hr training session with purchase), credits and new Version 2.0 turtorial available
    http://www.ermperformancetuning.com
    http://www.facebook.com/ERMPerformanceTuning

    [email protected]

  6. #6
    Tuner in Training
    Join Date
    Apr 2012
    Posts
    16
    Sorry about that, have it defaulted to that doSorry about that, have it defaulted to that does that everytime I open and save it.es that everytime I open and save it.
    Attached Files Attached Files