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360 Engine Idle

Discussion in 'Intermediate CJ-5/6/7/8' started by Tree cutter 08, Apr 28, 2020.

  1. Apr 28, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    Feb 14, 2019
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    111
    Got my engine broke in other day and trying to fine tune it. I can't get it to idle below 1000rpm. Cam is comp 268, edelbrock preformer intake and 1406 carb. Distributor is dui with livewires. Seems to run fine and rev quick. Cranks quick. Idle fluctuations a hundred or so rpms. Checked for leaks with starting fluid and found none. Vacuum gauge shows 12 to 15 at 1100rpms. Looses vacuum quick as soon as it drops below 1000 rpm and dies unless I give it a little gas. Played with the air/fuel mixture screws and runs best at 2 rounds backed out. Any ideas on what to do next?
     
  2. Apr 28, 2020
    Desert Runner

    Desert Runner Member 2024 Sponsor 2022 Sponsor

    Hickory, Pa
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    I know you don't want to here it but,..... I think you still have a vacuum leak ..... somewhere.

    are you running an egr valve? They always leak.
    Jay
     
    Lockman likes this.
  3. Apr 29, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    Feb 14, 2019
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    No egr. Only pcv and brakebooster and vacuum advance for distributor. Closed all lines to eliminate them leaking. Im going to go over it again to see if it's something I missed.
     
  4. Apr 29, 2020
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    X2, vacuum leak
     
  5. Apr 29, 2020
    sterlclan

    sterlclan Member 2022 Sponsor

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    bad booster?
     
  6. Apr 29, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    I blocked it off and eliminated that. Didn't get a chance to mess with it today but got a guy coming to help me figure it out next few days. Hopefully y'all are right and it's a simple vacuum leak.
     
  7. May 1, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    Feb 14, 2019
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    Ok guys, my help back out on me. Kept playing and playing and couldn't find a leak with starting fluid after trying 5 or 6 times. Decided to take the carb off my 304 which is a Edelbrock 500 cfmthat runs like a champ. Swapped it over and fired it up. After adjusting idle speed it sits and runs awesome. Sounds really mean with the cam. So, what am I to do with the other carb to get it to run this good? I think that eliminated my search for vacuum leaks. Just glad to hear the motor run and run good at idle
     
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  8. May 2, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    Feb 14, 2019
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    Well swapped carb back on with a new gasket and same thing. Will not idle. Edelbrock customer service is closed today. Can't figure it out. Floats have been adjusted and have cleaned idle circuits and played with air fuel mixture. Is it possible that the 500 cfm was allowing the right direction mixture and the 600 is to much air and I still have a vacuum leaks?
     
  9. May 4, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    Well I installed a new 600 cfm edlebrock and it runs great. Crazy strong. I'm baffled at what could have been wrong with it.
     
  10. May 5, 2020
    sterlclan

    sterlclan Member 2022 Sponsor

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    Bad carb?
     
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  11. May 5, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    I guess? It was brand new. Went through it 2 times and couldnt see anything wrong. Clean as a whistle. I ran across the same issue on another site. That carb issue was never resolved after being built by a carb expert.
     
  12. May 5, 2020
    Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I recently chased a Brand New MC for about 20 hours. Ruined my Hydroboost piston, which is not replaceable. It was faulty from the Factory & prittnear drove me crazy. Glad you got it.......
     
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  13. May 5, 2020
    Tree cutter 08

    Tree cutter 08 Member

    Cleveland ga
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    Went through 3 starters one time before I got on that worked. I use to think it was always me or something I did when changing new parts. New stuff can be faulty.
     
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  14. May 5, 2020
    Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Yep...... even when it's from your trusted , tried & true, long time supplier. It can be very frustrating.
     
  15. May 7, 2020
    sterlclan

    sterlclan Member 2022 Sponsor

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    Just cause it’s new don’t mean it is good.
     
  16. May 11, 2020
    officer_friendly

    officer_friendly Member

    Northern California
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    Is your 1406 manual or electric choke? I had this same issue on my holley TA 470, could not get idle below 1000. Something was wrong with my electric choke and the fast idle cam was stuck on. Check the fast idle linkage on your edelbrock. I ended up switching to a manual choke and love it, gives me the control to choke the engine exactly as needed.
     
  17. Jun 2, 2020
    ROBERT H SWARTOUT

    ROBERT H SWARTOUT New Member

    KALAMAZOO MI
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    May 16, 2020
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    transition ports on carb check into that. the amount of port exposed by the butterflys. on holley it can be adjusted on the 4 barrel side by the screw under the carb back by the choke assembly. on you tube thunderhead 289 shows on video how to adjust and why.
     
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