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  1. #1
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    Default Gas Pedal travel

    84 Ltd lx, 347, t5. The 347 came with an Edelbrock Pro flo 4 system. I installed a lokar throttle cable and it works fine. The problem is the gas pedal does not have enough travel to activate the secondaries on the throttle body. Any suggestions.

  2. #2

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    If by "works fine" you mean that the primary throttle plates are opening fully, but the secondaries aren't... that's not a function of the throttle cable, but of the secondary-opening link on the driver's side between the primary and secondary throttle levers... just the same as the multiple Holley double pumper carburetors that I have remedied, mostly even brand new out of the box, the link needs to be bent so that all four throttle plates open fully to WOT (wide open throttle), and then clearance with the link also needs to be verified/established at idle. If there isn't at least a slight bit of idle clearance (often the case) after bending the link for WOT, the link hole in the primary throttle lever needs to be filed with a small round file (in a direction that does not affect the link's pull for secondary opening) until there is some clearance at idle.

    Clearance at idle is important so that the secondaries are not holding the primaries open at idle or vice-versa... which renders idle speed setting screws useless.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  3. #3
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    Default

    Ye the primaries are opening, but the secondaries are not opening. It worked fine when the engine was in another car, that’s why I figured it was a throttle cable problem. I guess I will try to adjust it.

  4. #4

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    Never mind the clearance at idle stuff in my previous post... lack of information, and from having a look I see now that those throttle bodies have a two-piece primary throttle lever with springs and stops, where the primaries open some first, with a tab on part one that travels in an open arc slot on part two, and then part two (the outer lever, with the front of the link in it, that then connects to the secondary lever) of the throttle lever begins opening the secondaries. So... "but the secondaries are not opening"... at all, or they're not opening fully? If they're not opening at all, that indicates a problem with the two-piece primary throttle lever... and/or not opening fully indicates that the link centers need adjustment (bending the link)...

    Example images:







    Last edited by Walking-Tall; 06-09-2021 at 05:13 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  5. #5
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    Default

    The secondaries will open, but I run out of throttle cable before they open.

  6. #6

    Default

    Picture this if you will:
    If the throttle cable opens the primaries to standin' straight up at 90-degrees WOT (wide open throttle), there's nothing more that the throttle cable can do or needs to do... further gas pedal cable pull, if the primary WOT stop isn't right, would only serve to over-open the primaries past WOT (an airflow restriction just the same as if not opening fully). What ENTIRELY controls how soon and how far the secondaries get opened is a function of one of the two functions (tab and/or pull link) of that primary throttle lever mechanism.

    IF when stompin' ur foot-flat-to-the-floor, the gas pedal cable pull does indeed fully open the primary throttle plates (does it?), you have two options to getting those secondary throttle plates to also stand straight up open to 90-degrees WOT...

    Procedure options:
    1. Bending that tab upward some (this will open the secondaries a bit sooner, and with the proper amount of bending up of that tab, get them to fully open) that is shown encircled in yellow in the images above ... OR
    2. Remove the link between the primary and secondary throttle levers, and bend, and test, and bend some more if necessary, until the secondary throttle plates fully open when the primaries are fully open.

    What happened between when the engine was in another car and now yours... I don't know... but it's not a cable problem, UNLESS your throttle cable is not fully opening the primaries...

    Good luck with it.

    (always a question perplexes me... some car folk, and usually especially the followers of and believers of the superiority and users of EFI, often stating/repeating the mantras of "too much carb" or "that carburetor is too big" (horse feathers, poppycock, etc.)... thinking about this throttle not fully opening begs another question in my mind - do the "rules" somehow change with these Holley 4150-flanged throttle body EFI systems, and a 347 SBF needs or can use 1000cfm of airflow, as opposed to the usual 650cfm or so that's so often touted? lol...)
    Last edited by Walking-Tall; 06-10-2021 at 06:02 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  7. #7
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    Default

    When you explain it that way it makes sense. If primary is wide open, that’s as far as it goes. I will take your approach.

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