Results 1 to 7 of 7

Thread: Stand Alone 2.4 LE5 from 2006 Cobalt - I need HELP with my tune!

  1. Top | #1
    Forum Newbie
    Array suzukirmzrider's Avatar
    Join Date
    Sep 2016
    Last Online
    10-06-2016 @ 12:49 PM
    Posts
    4
    Thanks
    1
    Thanked 0 Times in 0 Posts

    Stand Alone 2.4 LE5 from 2006 Cobalt - I need HELP with my tune!

    Hey guys! New to the forum. I just found it and am happy I did. It appears that everyone is very helpful! Anyways, here is my issue.

    I am working on my sand car that has a 2.4 LE5 from a 2006 Cobalt SS. It has a 105 amp alternator on it from basically a 2005 cavalier, 2008 cobalt injectors, 2008 cobalt MAP sensor, running in speed density, and all other sensors are stock to the 2006 cobalt ss 2.4 LE5. It has an aftermarket air intake system (UMP offroad intake), header with no restriction, AEM fuel pump and Aeromotive fuel regulator set at 55psi idle. I have dual 14" SPAL fans on the radiator that are controlled by ECM.

    I am having trouble with my tune. The problems are:

    1) Idle surge. It will idle great for a while, then it will stumble and start idling bad, hunting up and down. The motor pulls hard off of idle.

    2) Once fans kick on at set temperature in the ECM, the will not shut off. They continue to stay on as long as the car is still running. It will pull coolant temps below 100 degrees F!

    This car was ran with a MEFI system, but I am so far away from MEFI tuners, I decided to go with a stock computer with VATS removed to run in stand alone. Since it ran great with the MEFI system, I have a hard time believing anything is wrong mechanically, and am confident it is in my tune. There are only a few things it could be: Crank Position Sensor, Knock Position Sensor, Throttle Body, Pedal, or the Tune itself. These are the only things that have changed since the car ran great on the MEFI tune.

    I have been using HP Tuners, so I will attach my files for anyone that can view them. ANY help or input would be GREATLY appreciated!! Thank you in advance.


    eee file is near WOT run
    06 Cobalt idle issue eee.hpl
    06 Cobalt idle issue.hpl
    06cobaltBuggy Kramer revF.hpt

  2. Top | #2
    Forum Newbie
    Array suzukirmzrider's Avatar
    Join Date
    Sep 2016
    Last Online
    10-06-2016 @ 12:49 PM
    Posts
    4
    Thanks
    1
    Thanked 0 Times in 0 Posts
    Here is a short clip of the engine running funny at idle. Not sure what to try. Anyone have any suggestions? Thanks in advance!

    https://youtu.be/SuENUrBqGjc

  3. Top | #3
    Super Moderator
    Array thewizard's Avatar
    Join Date
    Oct 2006
    Last Online
    10-06-2016 @ 01:52 AM
    Location
    Kansas City
    Âge
    34
    Posts
    4,472
    Thanks
    15
    Thanked 16 Times in 15 Posts
    Look over all your fan settings and make sure you're off temps have been adjusted to correlate with your on temps. As far as the surging watch your fuel trims to see how they are acting and play with the tune accordingly to dial it in.

    Nothing is difficult; some things just take more time.
    TAKE TO EXTREMES AND DOMINATE!

  4. Top | #4
    Forum Newbie
    Array suzukirmzrider's Avatar
    Join Date
    Sep 2016
    Last Online
    10-06-2016 @ 12:49 PM
    Posts
    4
    Thanks
    1
    Thanked 0 Times in 0 Posts
    Thank you for the input. I will mess around with the fan settings. As far as the fueling goes, LTFT's are 20% at idle. What would cause this and where would I need to start in order to get them down?

  5. Top | #5
    Super Moderator
    Array thewizard's Avatar
    Join Date
    Oct 2006
    Last Online
    10-06-2016 @ 01:52 AM
    Location
    Kansas City
    Âge
    34
    Posts
    4,472
    Thanks
    15
    Thanked 16 Times in 15 Posts
    The value is usually called injector constant. I don't recall which way you need to go with it off the top of my head.

    I just reread what your setup is......just cranking up your fuel pressure a little is another way. You'll have to let it learn, or reset the trims in your tuning suite for faster diagnosis of your changes.
    Last edited by thewizard; 10-06-2016 at 01:50 AM.

    Nothing is difficult; some things just take more time.
    TAKE TO EXTREMES AND DOMINATE!

  6. The Following User Says Thank You to thewizard For This Useful Post:

    suzukirmzrider (10-06-2016)

  7. Top | #6
    Forum Newbie
    Array suzukirmzrider's Avatar
    Join Date
    Sep 2016
    Last Online
    10-06-2016 @ 12:49 PM
    Posts
    4
    Thanks
    1
    Thanked 0 Times in 0 Posts
    Awesome! I will work on figuring those values out and report back. Thank You for your help!

  8. Top | #7
    Senior Member
    Array Brett85p's Avatar
    Join Date
    Aug 2014
    Last Online
    02-10-2017 @ 03:56 PM
    Location
    St Louis
    Posts
    150
    Thanks
    7
    Thanked 2 Times in 2 Posts
    I had a similar issue with my L61 when I changed to a header and 3 inch exhaust, trims can only go to +/-20% and can not keep up with the air flow, once it gets up to temperature it goes into a limp mode due to being extremely lean. You can increase the high RPM VE tables to compensate, basically you are telling the computer that you have more air passing through the system so it will supply more gas. In theory this can be bad for the injectors as it is increasing the duty cycle so you should really go to bigger injectors, I have injectors from a trailblazer now. I think that I ended up multiplying everything by 1.3 to get it to run right. Make sure you increase the VE offset % on the Engine page first or everything will max at 120 on the VE table. Once you get in the ball park you can go driving and log and tune further if you need. I have a wideband and at WOT it sits right on 13.2 between 4500 and 6500 rpm which is where I run it 90% of the time. (Engine is in a road racing car)

    Good Luck!


Tags for this Thread

Posting Permissions

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