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Thread: Possibly losing crank signal.

  1. #1

    Default Possibly losing crank signal.

    This is the first 2JZ engine that I attempted to tune, everything runs great till it gets above 5000 RPM. I never lose RPM signal, but RPM would drop roughly 2000 RPM from one frame to the next, which is mechanically impossible. The only thing that I can come up with is that it missed a crank trigger. Now this engine had 3 magnets installed on the crank with a Holley Hall-Effect sensor, and Holley Hall-Effect on the cam as well. I did a system log, which looked very strange to me. Most of the time I get 3 crank signals per cam signal, and once in a while I get 4. I thought that I should get 6 crank per each cam. I can send a system log if anyone cares to look at it.

  2. #2
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    Where are the magnets mounted on the crank? I think you should have 6 crank pulses per camshaft pulse as well. Gary
    Regards, Gary

  3. #3
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    Quote Originally Posted by ernie's 5oh View Post
    This is the first 2JZ engine that I attempted to tune, everything runs great till it gets above 5000 RPM.
    So does the System Log look correct until 5000 RPM? Meaning in accordance to my following statement below.

    Quote Originally Posted by ernie's 5oh View Post
    Now this engine had 3 magnets installed on the crank with a Holley Hall-Effect sensor, and Holley Hall-Effect on the cam as well.
    I did a system log, which looked very strange to me. Most of the time I get 3 crank signals per cam signal, and once in a while I get 4. I thought that I should get 6 crank per each cam.
    Yes, a six cylinder "1 Pulse/Fire" type crank trigger kit should transmit three pulses per crankshaft rotation, and six pulses per camshaft rotation. Camshaft turns at half speed of crankshaft.
    An eight cylinder engine uses a 4x crank trigger wheel. A six cylinder engine uses a 3x crank trigger wheel. A four cylinder engine uses a 2x crank trigger wheel. (LINK - See Figure #1)
    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/2500 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.

  4. #4

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    Looks the same throughout the RPM range, even after it drops 2000 RPM, still looks the same. I suspect the brackets for the crank & cam sensors that the owner made are part of the problem, not very sturdy. Another issue may be is where the cam magnet is installed, there are nuts that are inline with the sensor that could be causing a signal.

  5. #5

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    Had the car at the track last weekend and ran 4 tenths faster for his new personal best. Car would've gone a lot faster, but he ran out of injector.

  6. #6
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    Just curious, what was the crank/cam signal issue?
    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/2500 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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    Sorry Danny, I did post it but didn't go through. I discovered that the machine shop installed the magnets incorrectly. Two had south pole facing the sensor and one north pole on the balancer.

  8. #8
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    Thanks for the good update.
    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/2500 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.

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