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  1. #1
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    Default DIS Ignition

    Hi Danny, Scott. We're working on a buddies car. We are putting a DIS system on it, and we are having an issue with the timing below 2200 RPM jumping around. It will jump (at the crank) 10° ahead at idle. The amount the timing jumps is consistent, but the frequency it happens is not. Once above 2200 RPM it does not jump around.
    It's on a 400 SBC. He's using the Holley 60-2 wheel, with what I believe is a Cherry sensor you recommended he use on another thread. The air gap is at .025", but the sensor is slightly off center. He's also using a EFI Connection cam sync unit: https://www.eficonnection.com/home/p...nd-bbc-engines
    We recorded a datalog as well as a System Log. We don't see any missed events in the System Log.
    My first thought was to center the sensor and reduce the air gap a little to eliminate that as a cause.
    Do you know of any other things we should be looking at? Here's a zipped copy of his Global File (V4), datalog & System Log.
    Attached Files Attached Files
    Last edited by 81 TransAm; 10-05-2016 at 08:11 AM.

  2. #2
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    Default

    As you stated, center the crank sensor, and .025" sensor gap should be fine (that's what I run). Also, is the Inductive Delay correctly adjusted (LINK)?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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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    Yes, the Inductive Delay is set. It was off a few degrees and it needed to be raised.

  4. #4
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    Quote Originally Posted by 81 TransAm View Post
    We are putting a DIS system on it, and we are having an issue with the timing below 2200 RPM jumping around. It will jump (at the crank) 10° ahead at idle. The amount the timing jumps is consistent, but the frequency it happens is not. Once above 2200 RPM it does not jump around.
    Have you tried temporarily disabling the Idle Spark control (Idle ICF)? Does this happen when using the Enable Static Timing Set?
    The Global File & Datalog look fine. Did you notice something wrong in the Datalog you posted? If so, at what time (seconds)?

    It's on a 400 SBC. He's using the Holley 60-2 wheel, with what I believe is a Cherry sensor you recommended he use on another thread.
    Since it's a SBC, why isn't he using the Holley 554-117 Hall-Effect crank sensor that's included in the kit?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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
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    The Idle Spark control is disabled. We did not try enabling the Static Timing Test. We will try that next time we look at it. He bought the DIS Kit used, so it didn't have the correct sensor.

  6. #6
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    Quote Originally Posted by 81 TransAm View Post
    He bought the DIS Kit used, so it didn't have the correct sensor.
    Is this the person from this forum thread: LINK?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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.

  7. #7
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    Yes, that's him. Thanks.

  8. #8
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    Hi Danny. I was just reading your thread on Crank & Cam Sensor Setup: http://forums.holley.com/showthread....m-Sensor-Setup
    It states: 2.2 Cam Sync setup when using a 60-2 crank input.
    When using a 60-2 crank sensor wheel, this cam sync signal trigger MUST occur:
    • Before cylinder #1 is at TDC on the COMPRESSION STROKE, make sure that it is not occurring on the exhaust stroke.
    • It also MUST occur at least 8 teeth (approximately 50 degrees) before the “missing teeth” are read by the crank position sensor.

    By the look of our cam signal, it's happening on the 4th tooth after the missing teeth. This would make the signal happen late. Am I correct that I would need to advance the cam sync distributor housing, until the signal happens at least 8 teeth before the missing teeth?

    Click image for larger version. 

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