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Thread: Couple of Terminator Questions/Issues

  1. #11

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    I believe 30% is the default Parked Position for the IAC when TPS Position exceeds 0%. I would attempt a TPS AutoSet or possibly back off the main idle screw slightly, perhaps it's seeing more than 0% TPS but it's not enough to trip it over to 1%.

  2. #12
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    Quote Originally Posted by doldsen83 View Post
    I believe 30% is the default Parked Position for the IAC when TPS Position exceeds 0%.
    I think you mean the IAC Hold Position. The IAC Parked Position is only for starting.

    I checked the handheld and saw that the IAC was at 30%, TPS was at 0%, and confirmed that the target idle is set to 750. Any reason for the high idle?
    Are you sure the TPS Position isn't higher than 0%?
    Just because your foot is off the throttle, doesn't mean it's zero.
    Sounds like the TPS Position isn't always returning to 0%, and activating the IAC Hold Position.
    http://www.holley.com/data/Products/...R10653rev3.pdf (Holley Terminator EFI Manual - page 32)

    The TPS Position must be at 0% anytime the engine is at idle. This must be corrected as soon as possible.
    You may have to slightly back-off the idle speed screw (after a TPS AutoSet), so it's not on the verge of 1%.
    The TPS isn't always returning to 0% (it's between 0% & 1%), and activating the IAC Hold Position.
    Ensure your throttle linkage is returning freely, and use a stronger throttle return spring.

    32.4.1 IAC Ramp Down
    The Idle Air Control (IAC) motor is a stepper motor located in the throttle body that controls the idle speed of the engine by metering air. It also operates during engine cranking and when the engine returns back to idle. The settings here can adjust how that functions. The IAC moves from a position of 0% (fully closed, no air added) to 100% (fully open, maximum air flow).
    NOTE: If you change these settings, you must comprehend the function they perform. Contact Holley Tech if you have any questions.

    32.4.1A IAC Hold (IAC Hold Position)
    This is the position the IAC motor will “hold” or “freeze” at when the TPS moves above idle (when TPS becomes greater than 0%).
    If it is too high, the engine RPM will “hang” and not return to idle.

    32.4.1B Ramp Decay (Ramp Decay Time)
    This is the time (in seconds) it takes for the IAC to decay from the “IAC Hold Position” back to a “0%” position (Fig 76).
    It is a linear decay.

    32.4.1C RPM Start (RPM Above Idle to Start Ramp)
    This value is the RPM added to the target idle speed that the IAC will automatically start to ramp back down to idle (Fig 76).
    If this is too low, the engine RPM will “hang” and not return to idle.

    32.4.2 IAC Speed (Advanced Idle Control)
    This drop-down is used to select the type of IAC motor application that is being used (Fig 77). This selection drives the background parameters that control the IAC motor. These parameters have been fine tuned for each of these applications, eliminating the need for the user to perform further modifications.

    32.4.3 Idle Spark
    Idle spark is a feature active only when the ECU is controlling timing (only when using a small cap computer controlled GM HEI with the TERMINATOR™ systems). If enabled/checked, the ECU rapidly changes the timing at idle to help maintain a more stable idle (Fig 78).

    32.4.4 Startup IAC Position
    These parameters control the position of the IAC when the engine is cranking and immediately after it starts.

    32.4.4A IAC Parked (IAC Parked Position)
    This is the position the IAC motor will be at during cranking and immediately after the engine starts. If it is too high, the engine will be at too high of an RPM once it starts. Too low and poor starting will result. Note that this is a temperature based table. The value changed in the handheld offsets this entire curve (Fig 79).

    32.4.4B Hold Time (Startup Hold Time)
    This is the amount of time that the IAC will remain at the “IAC Parked Position %” (Fig 79).

    32.4.4C Decay Time (Startup Decay Time)
    This is the amount of time for the IAC to decay from the “IAC Hold Position” back to a “0%” position. It is a linear decay (Fig 79).
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 MT tires.

  3. #13

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    Quote Originally Posted by Danny Cabral View Post
    I think you mean the IAC Hold Position. The IAC Parked Position is only for starting.
    Oops wrong term, that's what I meant. Thanks for the correction Danny.

  4. #14

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    Quote Originally Posted by Danny Cabral View Post
    Are you sure the TPS Position isn't higher than 0%?
    Just because your foot is off the throttle, doesn't mean it's zero.
    Sounds like the TPS Position isn't always returning to 0%, and activating the IAC Hold Position.
    http://www.holley.com/data/Products/...R10653rev3.pdf (Holley Terminator EFI Manual - page 32)
    I'm going by the reading on the handheld, which was showing TPS 0% while the IAC position was 30%.

    The idle was normal after initial startup and for the first few minutes I was driving. I then noticed it holding around 1000 rpm while I was stopped at a couple of red lights. It held steady at 1000 rpm, never dropping back to 750. When I got back home, I left the truck running and it continued at high idle (1000 rpm in gear, 1200 or so in park - indicating the IAC was constantly at 30%). This is when I looked at the handheld to see that TPS was indeed 0% and IAC was 30%. I'll perform another TPS Autoset to see if that will cure the issue.
    Last edited by 3MAX; 04-23-2014 at 02:29 PM. Reason: Corrected TPS to IAC (typo)

  5. #15
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    Quote Originally Posted by 3MAX View Post
    ...(1000 rpm in gear, 1200 or so in park - indicating the TPS was constantly at 30%).
    TPS? Or did you mean IAC?
    Perform another TPS AutoSet. If that doesn't fix it, read the instructions in the box above.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, 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 MT tires.

  6. #16

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    Quote Originally Posted by Danny Cabral View Post
    TPS? Or did you mean IAC?
    Sorry, I meant IAC was constantly at 30%. I corrected it in the original post.
    Last edited by 3MAX; 04-23-2014 at 02:29 PM.

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