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Thread: 351C timong settings

  1. #1

    Default 351C timong settings

    I am having difficulty getting my motor to run properly with the atomic controlling the timing. Here are the details:



    351C bored .030 over, 10.4 CR.

    C6 with 2800 stall

    I have a return fuel line with regulator installed

    Cam 225/235 @.50

    MSD 8580 Dizzy locked out with 8421 rotor that modified to get the 15* retard

    MSD 6AL



    Firmware:

    Dash 2.0.4

    ECO 1.1.3

    Power 1.0.9



    AFR

    Idle 13.9 : 1

    Part Throttle 13.9 : 1

    WOT 12.9 1



    Target RPM 750

    Adv start RPM 850

    Total adv @ 2400 to be 34*

    Idle adv 10*

    Vaccum adv 10* ported



    ECT is 185*



    Cam setting is performance

    Pump Squirt 25%

    Power Valve Enrich 20%



    Diagnostics show no error codes



    Now the issue , when the timing is disabled the motor runs well however the RPM is around 1200 and the timing is at 15* BTDC. When the timing is enabled the motor runs rough and wants to die. I have a vaccum gauge attached with very low vac, vac with timing disabled is around 15".



    Now a couple of questions:

    * With timing disabled the IAC count is 0, is this normal?

    * With timing enabled IAC count is high, around 150 if I remember correctly. Is there a way to reset the throttle blades to factory settings so I can try this again?

    * Any reccomendations on what setup settings I should try?



    I tried to provide all the info needed, let me know if I missed anything. This really has me stumped.



    TIA

    -jbojo

  2. #2

    Default 351C timong settings

    Firstly, I wish you luck, I've been trying to get my Cleveland running for about 2 months now and I haven't made much, if any progress. Not trying to discourage you but not everyone's system is bolt it on and go like they show in the videos. My engine is quite a bit more radical than yours and I had to set my cam to the "Mild" setting to get it to run at all so you may want to give this a try.



    The IAC is really finnicky to set. Very small adjustments to the butterfly screws makes a huge difference so go slow and sneak up on it. There is also a "secret" that isn't well known or published that everyone should know. In my experience, the IAC is directly linked to your idle timing setting and idle RPM so if you play with the either of these you have to go back and set your IAC again. Nice to know so you're not wondering what the h3ll is going with the IAC when it changes all by itself. If I'm totally wrong on this, someone please correct me, maybe it's just my system that is like this.



    Give these suggestions some thought and let us know how it goes.

  3. #3
    Join Date
    Sep 2017
    Location
    Massachusetts
    Posts
    12

    Default 351C timong settings

    I have a pretty radical 393cu 351c stroker with a roller mechanical.

    For me, it was the low rev bucking or surging.

    Tried the mild setting and it is certainly better but still present.

    Bojo, I would update to the latest firmware for MSDtech will most likely ask you to do this.

    It does have some updates for the IAC.

    You do need to get those IAC values to the recommended level. Very small adjustments are key.

  4. #4

    Default 351C timong settings

    Thx for the tips.



    I went from performance to street/strip and it was worse. Right now idle adv is set to 10* and I believe recommended is 12* with the standard setup. Should I set it to 12* to start with?

  5. #5

    Default 351C timong settings

    I've got a 408 Cleveland that also has the bucking surging but I have other issues that I need to get sorted out and hopefully some fringe benefits will come with.



    I'm using the smallest Comp Cams roller Thumpr cam so mine should fall in the performance setting but the mild setting works the best. Don't know why but I think there's a Chebby guy in the MSD R&D department that's smirking right now.

  6. #6

    Default 351C timong settings

    I thought that I had the latest version of the FW. Where do I get it? When I go here it's what I already have.



    http://www.atomicefi.com/update.aspx



    BTW, is the IAC adjusted with timing enabled or disabled?



    thx

    jbojo

  7. #7

    Default 351C timong settings

    Sounds like your firmware should be good to go.



    IAC has to be adjusted with:

    1. The engine warmed up.

    2. Auto tranny in gear or manual tranny in neutral.

    3. Timing enabled if that's what you're going to run normally. If you're not going to have the EFI control timing then just leave it disabled. From what I've read, it is beneficial to have the EFI control the timing if you're not doing it now.

  8. #8

    Default 351C timong settings

    I missed commenting on one of your initial questions... resetting the throttle blades. To start from scratch, just turn the adjustment screws out until the blades are fully closed and slowly turn them back in until the blades just start to move. I would try one full turn on each screw from there as a starting point and if you're lucky, you'll be close and won't have to adjust too much from there. This will be a whole lot easier to do if you warm up your engine first. You should be able to dial it in fairly quickly that way, otherwise you'll have to wait for it to warm up and it could off by a bit while it's doing so and it won't want to run properly. The "sucking" sound that has come up in other threads is a dead give away that the blades are closed too much.

  9. #9
    Join Date
    Sep 2017
    Location
    Massachusetts
    Posts
    12

    Default 351C timong settings



    bojo wrote:

    I thought that I had the latest version of the FW. Where do I get it? When I go here it's what I already have.



    http://www.atomicefi.com/update.aspx



    BTW, is the IAC adjusted with timing enabled or disabled?



    thx

    jbojo

    The latest firmware in the link you posted is..

    - Dash – 2.0.7
    - EFI – 1.2.3
    - P.M. – 1.0.9

    You said earlier you had..

    Firmware:

    Dash 2.0.4

    ECO 1.1.3

    Power 1.0.9


  10. #10

    Default 351C timong settings

    bdud,

    You are right. I just updated the FW and it matches the latest. When I looked at the SD card it had those same files on it so I thought I had the latest ones loaded. I'll try the settings tomorrow to see if it made any difference.

    thx

    -jbojo

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