Results 1 to 6 of 6

Thread: Can't dial in idle after cam swap, 05 Gto.

  1. #1
    Tuner in Training
    Join Date
    Oct 2020
    Posts
    33

    Can't dial in idle after cam swap, 05 Gto.

    Hello, I just did a cam swap on my 05 Gto and I can't for the life of me get the idle sorted out. Mods include e85, procharger, longtube headers, magnaflow exhaust, and a ccp jam cam which was the only thing done during the cam swap, all other mods were previously dialed in on last tune.(Running speed density)
    Cam specs are: 230/242 .608"/.615" 115+4

    I have tried following step by step guides posted online but the gto is lacking many of the parameters that get edited and I can't seem to find a clear guide to dial in the gto's idle that's unique enough to work for it.

    I've tried modifying many different parameters without much luck, airflow final min., base spark, etc. Car would sometimes maintain idle at 1000, and then other times drop down to 300 or 600. I took it for a very quick test drive trying to see how it drove, it was late at night so I tried to keep moving to not upset the neighbors too much. Car would sometimes randomly die while coasting or stopping. It didn't want to crank back up after warm either, I lowered the cranking ve and I think it helped. I attached a log file of this along with my current tune file. Fyi, I already updated the VE table in this tune after seeing the log file. Airflow Min. final table is currently zeroed out.

    5-20-21 first drive.hpl
    5-6-21 gto for cam test3 after drive.hpt
    Last edited by 05silgto; 05-20-2021 at 11:55 PM.

  2. #2
    Senior Tuner
    Join Date
    Mar 2011
    Location
    Ripley, MS
    Posts
    1,865
    Your Minimum Airflow table is zero'd out. That's the main reason it won't idle. Just copy/paste the stock table back into it and multiply the entire table by 2. That'll be a good start. You'll probably have to add a little more, but that'll get you in the ballpark.
    It's pretty rich across the board. You'll want to lean it out at idle and cruise. At that point, you should be able to put a more reasonable idle speed in the tune...around 900 or so.

    As far as the hot start, just increase the startup airflow just a bit more at higher coolant temps.

  3. #3
    Tuner in Training
    Join Date
    Oct 2020
    Posts
    33
    Quote Originally Posted by kevin87turbot View Post
    Your Minimum Airflow table is zero'd out. That's the main reason it won't idle. Just copy/paste the stock table back into it and multiply the entire table by 2. That'll be a good start. You'll probably have to add a little more, but that'll get you in the ballpark.
    It's pretty rich across the board. You'll want to lean it out at idle and cruise. At that point, you should be able to put a more reasonable idle speed in the tune...around 900 or so.

    As far as the hot start, just increase the startup airflow just a bit more at higher coolant temps.
    Thanks, I saw in my log file that under dynamic airflow it was showing about 200 maybe around 1000 rpm and 180 around 800. Would these numbers be suitable to put in the min. airflow table, or does it not work the way I'm thinking? Also, how should I go about adjusting the idle base spark? It seems to like it when I lower it some but it could just be an incorrect observation from chasing my tail. I've heard most people say larger cams like more idle spark and then I've heard a few say the opposite.
    Thanks for the help, hopefully I'll have it at least drivable by the end of the day.

  4. #4
    Senior Tuner
    Join Date
    Mar 2011
    Location
    Ripley, MS
    Posts
    1,865
    Quote Originally Posted by 05silgto View Post
    Thanks, I saw in my log file that under dynamic airflow it was showing about 200 maybe around 1000 rpm and 180 around 800. Would these numbers be suitable to put in the min. airflow table, or does it not work the way I'm thinking? Also, how should I go about adjusting the idle base spark? It seems to like it when I lower it some but it could just be an incorrect observation from chasing my tail. I've heard most people say larger cams like more idle spark and then I've heard a few say the opposite.
    Thanks for the help, hopefully I'll have it at least drivable by the end of the day.
    It would typically be in the 12-15 gms/sec range on a setup like yours. Probably around 110-140 lbs/hr.

    A cam of that size will like 20-22 degrees at idle.

  5. #5
    Tuner in Training
    Join Date
    Oct 2020
    Posts
    33
    Quote Originally Posted by kevin87turbot View Post
    It would typically be in the 12-15 gms/sec range on a setup like yours. Probably around 110-140 lbs/hr.

    A cam of that size will like 20-22 degrees at idle.
    Thanks, made some adjustments, I'm gonna start off with a high airflow final min. and work my way down.
    5-21-21 gto for cam swap adjusted airflow min., cranking airflow(warm), base idle spark, coastdo.hpt

    edit: uploaded the tune, it was much better than before, thank you so much, idle was really strong. I lowered the idle airflow quite a bit until spark advance correction went from high negatives to very low negatives. I set the idle at 800 and have been driving it around tuning the VE table. Idles almost perfect now, I still had a slight issue with warm starts, I added some more cranking airflow and I am waiting to see if that helps.
    I'll post a log later in case there is anything I can improve upon.

    Do you have any suggestions on how I should modify my spark tables (for cruising and wot) for a cam of this size?
    Last edited by 05silgto; 05-21-2021 at 08:04 PM.

  6. #6
    Tuner in Training
    Join Date
    Oct 2020
    Posts
    33
    Here is my log file and tune. My vacuum is pretty low, I've heard you should try shooting for the highest vacuum possible. How would I go about doing this?

    5-24 drive home.hpl
    5-24 edit at work.hpt

    Car is pretty driveable now. I feel like the idle can be better and it is a little rough here and there which could just be a normal side effect from having a cam.