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Thread: Letís talk about sticking secondaries.

  1. #1

    Default Letís talk about sticking secondaries.

    My car has been running very well since my 4150 Stealth install 3 or 4 months ago. Out of the blue, I started getting intermittent high idle issues. Turns out it's the secondary butterflies not closing all the way at times. Iíve posted some IAC questions (thinking that was my issue), but this is definitely it.

    So what's my most likely cause? I caught it in the act today, and it didnít feel at all stiff. Took very little effort to manually close the secondary shaft with my finger. Of course, itís pretty much impossible to reproduce in the garage with the engine off. It does seem to occur more often when the throttle body isnít hot. Should I tighten the spring? Try to center the butterflies? Thanks.

  2. #2
    Join Date
    May 2019
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    Ct
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    203

    Default

    I believe over tightening the flange on the intake can distort it enough to bind the shaft. At least on carbs, so it could be possible on a throttle body too. Heat could cause the TB to expand and bind. That could be one theory.

  3. #3

    Default

    I guess I could double check the torque on the base, but it really didn’t seem jammed/stiff when I moved it closed by hand. It’s pretty intermittent, and a blip of the throttle fixes it if it happens when driving. I guess I’ll play with it some more in the morning after the engine cools off. Seems worse when it’s cool.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
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    25,129

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    Tightening the secondary shaft spring one turn usually resolves the problem. If not, then investigate recentering the throttle blades.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232į-244į duration/.623" lift/114į LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  5. #5

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    Any technique that works well for tightening the spring?

  6. #6
    Join Date
    Dec 2009
    Location
    Connecticut
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    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232į-244į duration/.623" lift/114į LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  7. #7

    Default

    Just an an update to this. I did find my secondaries to be mechanically jamming intermittently. There was an audible pop when I freed them up with my hand the last time I was troubleshooting it.

    I didn’t tighten the spring, as that really didn’t seem to be my problem (though it could fix it I suppose). That sucker is already really wound tight on the 4150 Stealth, too.

    Anyway, I ended up taking the unit off and adjusting the secondary throttle plates. I noticed some scuff marks in the secondary bore when I was doing this. Not sure why this happened, but it’s been good so far. If it happens again, I guess I’ll be sending it to Holley to replace/repair.

  8. #8
    Join Date
    Dec 2009
    Location
    Connecticut
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    25,129

    Default

    Correct, this problem isn't rectified by tightening the secondary shaft spring. The throttle blades must be recentered: https://forums.holley.com/showthread...5168#post55168 (Read posts #6 & #8.)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232į-244į duration/.623" lift/114į LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

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