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Thread: Timing Off By 10° Once Started

  1. #1

    Default Timing Off By 10° Once Started

    I'm embarrassed posting this as I've been reading and rereading all the timing and idle tuning post for a week now but this has me stumped. I set the base timing to 11°, confirmed with timing light and injectors disconnected, and entered that into the cranking parameters. As soon as I start the engine, the ECU reads 10° higher than what the timing light says (ECU says 29°, timing light only reads 19°). I've also been unable to get the idle speed down as it's consistently 300-400 above the setting.

    Things I've tried:
    1) Re-Read http://forums.holley.com/showthread....ing-Holley-EFI &
    Read http://forums.holley.com/showthread....e-Tuning-Notes
    2) Verified multiple times that the base timing with light is set at 11° with injectors off
    3) Unchecked the idle spark setting and made sure there are no modifiers on
    4) Set the Enable Static Timing Set to 30° and revved engine. The timing did not move but it was still off by 10°
    5) Changed the ignition reference angle. It brought it closer but timing was still off by 6-10°
    6) Adjusted idle screw and reset TPS (never can get the IAC down to 5%).
    I backed the idle screw all the way out and engine dies as expected and would not start.
    TPS reads 0-1% but idle is still always high - set for 875 but is usually around 1200

    These are probably 2 separate issues but feel the timing needs to be resolved first. Any help will be appreciated.

    System: HP EFI, 383 SBC, Holley Stealth Ram
    Software: V2.2.0.3, Firmware: 587 (was just received new from Holley).
    Last edited by Magisnyc; 12-01-2013 at 02:57 PM. Reason: spell check

  2. #2
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    Quote Originally Posted by Magisnyc View Post
    5) Changed the ignition reference angle. It brought it closer but timing was still off by 6-10°
    What does your ignition system consist of?
    Are your Ignition Parameters correctly programmed?
    Ignition Type ............. ― ?
    Crank Sensor Type ..... ― ?
    Sensor Type .............. ― ?
    Inductive Delay .......... ― "adjusted per application" ( Synchronization info.)
    Ignition Reference Angle ― ?
    Cam Sensor Type ........ ― ?
    Sensor Type .............. ― ?
    Output Setup Type ..... ― ?
    Dwell Time ................. ― ?

    6) Adjusted idle screw and reset TPS (never can get the IAC down to 5%).
    I backed the idle screw all the way out and engine dies as expected and would not start.
    TPS reads 0-1% but idle is still always high - set for 875 but is usually around 1200
    Adjust the idle speed screw on throttle body, to achieve an IAC Position of about 3% at hot idle.
    Remember to perform another TPS AutoSet, whenever you adjust the idle speed screw on the throttle body.
    If the idle speed screw is unscrewed too far, the engine is inhaling air from an additional source - vacuum leak.
    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/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  3. #3

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    Quote Originally Posted by Danny Cabral
    What does your ignition system consist of?
    GM HEI small cap distributor. MSD Blaster coil.

    Are your Ignition Parameters correctly programmed?
    I only see those other values if I choose Custom ignition type. With GM HEI selected I don't see those options.

    Ignition Type ............. ― GM HEI (Computer Controlled)
    Ignition Reference Angle ― 10°
    Inductive Delay .......... ― 240.0 usec
    (I did not adjust this. With Enable Static Timing set to 30°, the timing was steady at 4000 RPM, even though timing light read 20°.)

    I will check again for vacuum leak but did not find any spraying carb cleaner around the manifold.

  4. #4
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    Quote Originally Posted by Magisnyc View Post
    I only see those other values if I choose Custom ignition type. With GM HEI selected I don't see those options.
    Correct, the other parameters only appear for other ignition types.

    Ignition Reference Angle ― 10°
    Correct, leave it at 10°.

    Inductive Delay ― 240.0 usec
    (I did not adjust this. With Enable Static Timing set to 30°, the timing was steady at 4000 RPM, even though timing light read 20°.)
    If the timing doesn't advance or retard when you rev the engine to 4000 RPM, the Inductive Delay is correctly set.
    However, at idle speed, physically turn the distributor to synchronize the timing (Idle Spark control temporarily disabled).

    I will check again for vacuum leak but did not find any spraying carb cleaner around the manifold.
    Something isn't right...idle speed screw completely unscrewed and the engine idles at 1200 RPM.
    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/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  5. #5

    Default

    Quote Originally Posted by Danny Cabral View Post
    If the timing doesn't advance or retard when you rev the engine to 4000 RPM, the Inductive Delay is correctly set.
    However, at idle speed, physically turn the distributor to synchronize the timing (Idle Spark control temporarily disabled).
    If I'm understanding correctly, even though I set the timing with the injectors unplugged, I still need to turn the distributor while running to match the ECU? Do I then have to go back and change the value put in for cranking timing?

    Quote Originally Posted by Danny Cabral View Post
    Something isn't right...idle speed screw completely unscrewed and the engine idles at 1200 RPM.
    No - when I backed off the idle screw, the engine did choke and die. Apologies if that was unclear.
    Question on the IAC Hold Position - What should this value be? It seems that when the engine is warm, the online IAC position defaults to whatever it is set to. Currently mine is at 10%.
    Last edited by Danny Cabral; 12-01-2013 at 06:22 PM.

  6. #6
    Join Date
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    Quote Originally Posted by Magisnyc View Post
    If I'm understanding correctly, even though I set the timing with the injectors unplugged, I still need to turn the distributor while running to match the ECU?
    Yes.
    The first timing synchronization is physically turning the distributor at idle (Idle Spark control temporarily disabled).
    The second timing synchronization is electronically adjusted (Enable Static Timing Set - Inductive Delay setting).
    Synchronizing the Cranking Timing (with the injector harness temporarily disconnected) is just a preliminary setting, before the initial start.

    Do I then have to go back and change the value put in for cranking timing?
    It should then be synchronized. I don't know why there's a discrepancy.

    Question on the IAC Hold Position - What should this value be? It seems that when the engine is warm, the online IAC position defaults to whatever it is set to. Currently mine is at 10%.
    It's your preference. I use 20%.

    EFI Software Help Information/Instructions:
    ‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics.
    ‒ When navigating the software, click "Help ?", drag it to any parameter and click again.
    ..This automatically opens the definitions for that specific parameter.
    ‒ Tuning information can be read by clicking the F1 key, when you're viewing any screen.
    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/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

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