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Thread: Cam/crank randomly not syncing.

  1. #1

    Default Cam/crank randomly not syncing.

    My car busts up randomly. It ran fine at the track for two all engine passes. The first nitrous pass it spun the tires and backfired through TB and exhaust. I thought it just hit the rev limiter. The next weekend I made another pass. It hooked and when I got to 7000 RPM it sounded like a rev limiter. I looked at the datalog and it showed “Sync” then RPM then sync then RPM, etc. I also went back and looked at the datalogs from the weekend before. Engine passes everything looked great. The nitrous pass it shows “sync” on RPM readout at 7500 or so. I looked at Diag #6 #7 it’s shows #6 go up. It will now pop and show syncing on RPM gauge Holley 3.5" touchscreen. When I just rev it in neutral.

    Crank sensor is .058” air gap.
    No signs of sensor hitting wheel.
    Pulled alternator belt off and still does it.
    Checked grounds and all seem well.
    Unplugged I/O harness (controls fans, water pump, nitrous progressive, vacuum sensor, driveshaft sensor) still does it.

    351W
    Holley HP
    MSD 85061 cam sync
    Holley 556-115 crank trigger
    Holley 558-118 Main Harness
    Holley 558-431 Cam/crank harness
    OEM LS coils/harness

  2. #2
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    Quote Originally Posted by RealTeal93 View Post
    Crank sensor is .058” air gap.
    Holley 556-115 crank trigger
    That air gap is way too much.
    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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    It’s funny you say that. I just tightened it up to .040”. I haven't cranked it though. Do you suggest something different? The instructions said .040" to .080”. Also, I read something about getting power for the crank sensor & cam sensor from a different pin. Do you suggest I do that?

  4. #4
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    Quote Originally Posted by RealTeal93 View Post
    It’s funny you say that. I just tightened it up to .040”. I haven't cranked it though. The instructions said .040" to .080”.
    That's a misprint from their other 554-118 Hall-Effect crank sensor instructions for a 4x MSD Flying Magnet crank trigger kit.

    Do you suggest something different?
    Yes, I suggest .030" air gap for missing teeth type crank trigger kits.

    Also, I read something about getting power for the crank sensor & cam sensor from a different pin. Do you suggest I do that?
    Originally Posted by Danny Cabral
    Crank & Cam Sensor Wiring Tips:
    The 10-pin Ignition Connector has one "Chassis Ground" (loose black wire ground) and two "IPU Grounds" (clean ECU ground). Don't use "Chassis Ground" to ground an ignition module (or crank & cam sensors). It's quick & easy to move the ignition module ground wire from (cavity) pin D "Chassis Ground" to pin C or G "IPU Ground", where it should be.

    If you don't have the actual Metri-Pack terminal release tool, a "safety pin" will work.
    It just needs to be a stiff wire between .030"-.035" in diameter to release the terminal tab.
    Then reopen (bend) the terminal tab before reinsertion, so it will clip (lock) into the cavity.
    http://www.whiteproducts.com/removal_tools.shtml (T-6 Micro Terminal Release Pick Tool)

    Also, don't use (cavity) pin E "Switched +12V" from the 10-pin Ignition Connector, to power an ignition module (or crank & cam sensors), unless you've modified the wiring source to connect from pin B20 - EST 12V Output (P1B ECU Connector). This LINK explains why & how to do it.
    http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual, Sections 2.1 "Pin-Outs" & 13.0 "Wiring Appendix")
    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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    Edm, AB
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    Quote Originally Posted by RealTeal93 View Post
    My car busts up randomly. It ran fine at the track for two all engine passes. The first nitrous pass it spun the tires and backfired through TB and exhaust. I thought it just hit the rev limiter. The next weekend I made another pass. It hooked and when I got to 7000 RPM it sounded like a rev limiter. I looked at the datalog and it showed “Sync” then RPM then sync then RPM, etc. I also went back and looked at the datalogs from the weekend before. Engine passes everything looked great. The nitrous pass it shows “sync” on RPM readout at 7500 or so. I looked at Diag #6 #7 it’s shows #6 go up. It will now pop and show syncing on RPM gauge Holley 3.5" touchscreen. When I just rev it in neutral.
    First I'd like to ask if this has been resolved. I'd also like to add my similar problem below.

    I'm having these same issues. Everything is fine until I get into about 6500-7500 RPM range. Lose power, comes back momentarily. My main issue is identical. The Digital Dash goes from producing an RPM to saying SYNCING. I haven't run a system log yet. But does anyone know if that SYNCING means that it lost cam sync specifically or crank trigger or is this an unknown event as to what it means directly? I'd like this to be defined for future people troubleshooting if possible.

    I was told by a local shop they've had to build a better Crank & Cam trigger harnesses as the Holley product did not do a good enough job of shielding from EMI. They said I didn't need the boots or even resistor plugs for that matter. I'm not saying this is true, but is there room for improvement on that harness? So I'd also like to add that I did buy the NGK resistor boots and some Super Conductor wires to see if that helps. I will add my findings soon.

    BBC 548 Twin S475.
    MSD Cam Hall-Effect cam sync distributor.
    60-2 Trigger wheel with Holley Hall-Effect sensor.
    D585 coils (LSx).
    Holley shielded cam & crank trigger harness.
    Non resistor plugs (no choice in my heat range for a resistor).
    MSD Street Fire wires. Mike

  6. #6
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    Quote Originally Posted by mdigs View Post
    First I'd like to ask if this has been resolved. I'd also like to add my similar problem below.
    Yes, his crank sensor air gap was way too much. See post #4.

    Everything is fine until I get into about 6500-7500 RPM range. Lose power, comes back momentarily. My main issue is identical. The Digital Dash goes from producing an RPM to saying SYNCING. I haven't run a system log yet. But does anyone know if that SYNCING means that it lost cam sync specifically or crank trigger or is this an unknown event as to what it means directly? I'd like this to be defined for future people troubleshooting if possible.
    This means the ECU lost the RPM signal and had to reset itself. Probably a crank sensor air gap issue. What's the sensor air gap set to?

    I was told by a local shop they've had to build a better Crank & Cam trigger harnesses as the Holley product did not do a good enough job of shielding from EMI. They said I didn't need the boots or even resistor plugs for that matter. I'm not saying this is true, but is there room for improvement on that harness?
    LOL! If you're referring to the Holley 558-306 Universal Crank & Cam Sensor Harness, it's a great harness! I used it for eight years on my previous engine/vehicle.
    If you're referring to the 558-431 Crank & Cam Ignition Harness, I'm currently using it on my Mustang (1˝ years and no problem). Both are shielded harnesses.
    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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    Jun 2019
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    Edm, AB
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    Quote Originally Posted by Danny Cabral View Post
    This means the ECU lost the RPM signal and had to reset itself. Probably a crank sensor air gap issue. What's the sensor air gap set to?
    My air gap is set to about .030" without any contact at all. So by saying "lost RPM signal", are you inferring that this is specifically crank trigger not cam sync related?

    LOL! If you're referring to the Holley 558-306 Universal Crank & Cam Sensor Harness, it's a great harness! I used it for eight years on my previous engine.
    That is the harness I'm using, yes. I'm experiencing EMI interference by the sounds of it. It's a relative question. I wouldn't know unless I asked. I'm only going off of what was mentioned to me. I appreciate the input. Thanks.

  8. #8
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    Quote Originally Posted by mdigs View Post
    My air gap is set to about .030" without any contact at all. So by saying "lost RPM signal", are you inferring that this is specifically crank trigger not cam sync related?
    It could be either sensor losing signal. If a regular datalog indicates an "RPM Error" when scrolling through the problem area, then it's time for a System Log to confirm which sensor flatlines.

    Record a System Log to verify crank & cam sensor signals. Check mark the "RPM", "Crank" & "Cam" channels. Look for a uniform,
    uninterrupted crank or cam sensor signal pattern. The crank or cam sensor signal should never flatline (no pulse) or indicate an
    RPM "Error" anywhere. Also, fully charge the battery and ensure the engine is cranking fast enough, at least 100+ RPM. Another
    common issue, is trying to analyze a compressed view of a long System Log. Zoom In for detail - click & hold at one point of the
    datalog, and drag & release to another point nearby. It's best to record short System Logs/Datalogs that capture the problem.
    http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log Information)

    That is the harness I'm using, yes. I'm experiencing EMI interference by the sounds of it. It's a relative question. I wouldn't know unless I asked. I'm only going off of what was mentioned to me. I appreciate the input. Thanks.
    The 558-306 & 558-431 Crank & Cam Ignition Harnesses have shielded wire, which will mate to the ignition connector.
    The Hall-Effect crank & cam sensors are wired as shown in the Holley EFI Wiring Manual:
    http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual - Figure 11/12, Page 20/21)

    Custom Hall-Effect sensors and/or shielded harnesses:
    1) The ECU already has the pull-up resistor for sinking output (open collector) sensors inside, so don't add anything.
    2) The ECU already has the shield (drain) wire connection/pin grounded inside, so don't ground it at the sensor end.
    http://www.newark.com/pdfs/techartic...haWire/USC.pdf (Shielded Wiring - look for "drain wire" on page 2 & 3.)
    Think of the shield wire as an antenna pointing to the sensor; it's only supposed to be grounded at the ECU end.
    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.

  9. #9
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    My apologies, I have this Holley 558-431 crank/cam sensor harness (terminated).

    - Switching to smart coils during this, so I might not have consistent troubleshooting data on the equipment I was previously running.
    - Also running the cam & crank sensor completely separate from the rest of the harness, right now it was among the other wiring.
    - Taking all the steps possible from other threads I have read to get this solved.
    I will update with any findings once I'm back online with this unit. Thanks for the help so far.

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