Results 1 to 12 of 12

Thread: Cammed C5 stumbles when going into gear. Cracker or follower?

  1. #1
    Advanced Tuner
    Join Date
    Jun 2018
    Posts
    603

    Cammed C5 stumbles when going into gear. Cracker or follower?

    What would you guys change to add some air during a gear shift. Car just seems to stumble for a second once you put it n gear. Drives fine, fuel trims are good, idle is great.

    Is this more of a cracker or follower issue?

  2. #2
    Advanced Tuner
    Join Date
    Jan 2015
    Posts
    563
    Post a log of the issue and add cracker and follwer as well as idle air trims to your pid list

  3. #3
    Advanced Tuner
    Join Date
    Dec 2019
    Location
    MS
    Posts
    565
    Throttle cracker gives you extra airflow based off RPM VS MPH.
    Throttle Follower gives you extra airflow based off TPS vs MPH

    If you need airflow changed for a different gear at idle it will be your based airflow table. But Timing also has a table for P/N and Gear so if there is a pretty decent difference between those tables it can cause a issue.

    What size cam and what torque converter?

  4. #4
    Tuner
    Join Date
    Jul 2022
    Location
    Roxana, IL
    Posts
    114
    Quote Originally Posted by RDF1 View Post
    Throttle cracker gives you extra airflow based off RPM VS MPH.
    Throttle Follower gives you extra airflow based off TPS vs MPH

    If you need airflow changed for a different gear at idle it will be your based airflow table. But Timing also has a table for P/N and Gear so if there is a pretty decent difference between those tables it can cause a issue.

    What size cam and what torque converter?
    I'm following this post to learn. Thank you for your explanation! I'm new and to clarify the terminology "throttle cracker" = "idle cracker airflow" and "throttle follower" = "idle follower airflow"???
    then from post #2 the term "idle air trims" is "idle adapt (STIT)"??
    Building Automatic Transmissions since 1978
    "Most people do not listen with the intent to understand; they listen with the intent to reply."--Ernest Hemingway.

    Black 2000 S10 Base 2.2L Flex Current LS10 swap project
    Red 2000 Blazer LT 4x4 3.73 SOLD
    Red 1998 S10 SS 4.3L Deceased 10/31/2014

  5. #5
    Advanced Tuner
    Join Date
    Dec 2019
    Location
    MS
    Posts
    565
    That's not an exact description. just a quick explanation to get you thinking in the right direction.
    But yea your heading in the right direction. Look at the channels and do some data logging. you will see where its using which airflow adder and how fast they decay out.

    If you post your current tune and a data log of the stumble. we might can help you figure it out.
    I use EFILive majority of the time so that is the table names im used to using, i forgot to use the correct ones for HPT.

  6. #6
    Advanced Tuner
    Join Date
    Jun 2018
    Posts
    603
    BTR stage 2 cam on a stock converter. So it's not ideal. Customer plans on coming back for the converter in the summer. It just bogs when going into gear, especially when it's not at operating temp.

  7. #7
    Advanced Tuner
    Join Date
    Dec 2019
    Location
    MS
    Posts
    565
    Is it the 227/238 cam?
    I have to turn down several tunes a month cause the kids kept getting big cams put in their trucks and they dont want to spend the money for a converter plus they have 35"+ tires with stock 3.42 gears and they just cant comprehend how this whole deal works. They go from tuner to tuner to tuner and never satisfied.

    Have you tried to give it some more airflow in gear?

  8. #8
    Advanced Tuner
    Join Date
    Jun 2018
    Posts
    603
    Yes, 227/238 but it's in a Corvette and not a truck.

    Yes, I added air in gear and it holds the idle just fine the rest of the time. Just when it gets first put into gear. Once it's warmed up you don't notice it.

  9. #9
    Tuner in Training
    Join Date
    Jul 2020
    Posts
    10
    Quote Originally Posted by RDF1 View Post
    Is it the 227/238 cam?
    I have to turn down several tunes a month cause the kids kept getting big cams put in their trucks and they dont want to spend the money for a converter plus they have 35"+ tires with stock 3.42 gears and they just cant comprehend how this whole deal works. They go from tuner to tuner to tuner and never satisfied.

    Have you tried to give it some more airflow in gear?
    I'm a pretty old kid, 30.5" tires (not huge mud boggers,) 4.10 gears, 3.35 1st gear (T56,) in a ~4700 LB GMT800 pickup. 220/220 .600 .600 cam (Texas speed 220r.) When I bought this cam more than 2 years ago it was to go into a 4.8, 4L60E! I got busy, and now I have an LQ4 6.0 with 243's. If you see this, I feel as though this cam will do well in this app, but do you know of any that would be better?

    I know this is derailing OP's thread so if you want, you can send me a PM, or just ignore..

    To OP: what is your timing advance doing during the gear shift?? Also, since it's only when cold, what are the differences in logs between cold/warm operation?
    Last edited by eighty6gt; 02-02-2023 at 06:44 AM.

  10. #10
    Advanced Tuner
    Join Date
    Jan 2015
    Posts
    563
    Get a log of the issue and post it up. Perhaps we can see the cause in action.

  11. #11
    Senior Tuner
    Join Date
    Nov 2006
    Posts
    2,605
    Quote Originally Posted by RDF1 View Post
    Is it the 227/238 cam?
    I have to turn down several tunes a month cause the kids kept getting big cams put in their trucks and they dont want to spend the money for a converter plus they have 35"+ tires with stock 3.42 gears and they just cant comprehend how this whole deal works. They go from tuner to tuner to tuner and never satisfied.

    Have you tried to give it some more airflow in gear?
    Amen. We can get it running right but your mid 230's duration cam in a otherwise stock tahoe with stock manifolds / converter/ and awful gearing is going to make shit "useable" power and get terrible mileage. I thought about offering a consulting service seeing how I've been doing this for so long and I drive all kinds of setups.. It would be a better deal for the customer and me if we pick out a good package.. but realistically no one wants to listen anyway. I'm sure tiktok youtube and facebook know better.



    I digress anyway..

    Do you have a wideband on it? How is the base timing tables in park and neutral.

    If the VE table is just a touch rich in the higher kPa areas around idle it will make this dip worse.

    Timing in the base park an neutral tables can help offset this.
    Tuner at PCMofnc.com
    Email tuning!!!, Mail order, Dyno tuning, Performance Parts, Electric Fan Kits, 4l80e swap harnesses, 6l80 -> 4l80e conversion harnesses, Installs

  12. #12
    Senior Tuner
    Join Date
    Jun 2004
    Location
    405
    Posts
    2,287
    Everyone needs to over cam a vehicle at least once in their life so they learn. I learned my lesson back in 1972.