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Thread: 36x With Cam Sync

  1. #1

    Default 36x With Cam Sync

    Hey Danny. This one has me stumped. BBC CNP customer has a Holley 36x crank trigger and an MSD cam sync module. It does the same thing in both V4 & V5, and both have the crank & cam set for Digital Rising per the instructions. Engine runs fine, but just after the engine starts it loses cam/crank briefly. The datalog actually shows STALL, and then resync. This is barely perceptible except the engine RPM drops when this happens, then it quickly recovers, from then on all is well. As a diagnostic, I turned off the cam and switched to waste spark. Works fine, no drop out. So it's somehow related to the cam signal being used with a 36x crank. Any ideas?
    Last edited by fastmanefi; 01-22-2020 at 09:22 PM.

  2. #2
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    Quote Originally Posted by fastmanefi View Post
    BBC CNP customer has a Holley 36x crank trigger and an MSD cam sync module.
    I also have the Holley 36-1 crank & MSD 1x cam sensors on my SBF, but I use Digital Falling. (I never use Digital Rising.)
    Years ago, I experienced this same starting condition on my 508" BBF with a custom 60-2 crank trigger & a 1x cam sensor.
    Also, read the third paragraph below and pay special attention to the modified B20 +12V wiring LINK. It seems like the culprit.

    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: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, BBK 80mm TB, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 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, B&M Hammer shifter, 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. #3

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    Thanks Danny. The system has another characteristic that surprised me. "DIS Coil-On-Plug" is selected, yet after the engine is running the customer tells me he can rotate the MSD Cam module almost all the way around and the engine keeps running. That tells me that the software is using the 36x and waste firing even though it's clearly set otherwise.

    I often use "DIS Coil-On-Plug" with a MSD 4x magnet crank trigger and you must have the Cam Sync positioned correctly or the engine won't run. THAT makes sense to me, but not caring about the Cam Sync even with DIS CNP selected makes no sense to me.

  4. #4

    Default

    Danny, what's your thought on my last comment?

    "DIS Coil-On-Plug" is selected, yet after the engine is running, the customer tells me he can rotate the MSD Cam module almost all the way around and the engine keeps running. That tells me that the software is using the 36x and waste firing even though it's clearly set otherwise.

  5. #5
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    I'm not sure what's happening, that's strange. Maybe this is one of those corrupt Global File or corrupt ECU firmware issues.
    http://forums.holley.com/showthread....2193#post72193 (EFI Software/ECU Firmware Problems)
    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, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, BBK 80mm TB, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 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, B&M Hammer shifter, 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. #6

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    I'll play around with it and get back to you if I find something.

  7. #7

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    Quote Originally Posted by fastmanefi View Post
    Danny, what's your thought on my last comment?

    "DIS Coil-On-Plug" is selected, yet after the engine is running, the customer tells me he can rotate the MSD Cam module almost all the way around and the engine keeps running. That tells me that the software is using the 36x and waste firing even though it's clearly set otherwise.
    Sounds like a diagnostic dead end to me. Don't get too hung up on something like that. I've seen it happen too often.

  8. #8

    Default

    Once the customer changed the wiring per Danny's notes, and he changed to Digital Falling, the system now acts as you'd expect. Thanks for your help Danny.
    No drop out after the start and the cam sensor is now very aware of it's position. What I did not know is that the algorithm will switch to waste-fire with a missing tooth type crank trigger if the cam signal faults. That's why it appeared to not care, but it does. More to follow after I scope injector signals and do a System Log.

  9. #9
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    Quote Originally Posted by fastmanefi View Post
    Once the customer changed the wiring per Danny's notes, and he changed to Digital Falling, the system now acts as you'd expect. Thanks for your help Danny.
    You're welcome. It's actually a very common issue. I've received a lot of positive feedback from the B20 +12V wiring modification.

    Another interesting feature of the latest V5 EFI software/ECU firmware:
    Added new Cam Sensor Type “Single Pulse – Ignore Cam After Start” – This choice operates the same as the “Single Pulse” selection, except once over the crank to run RPM the cam sensor input is ignored. If a loss or error occurs of the cam signal occurs, engine operation is not affected. This selection is not recommended for Coil-on-Plug applications as a loss of crank signal integrity can cause incorrect coil firing sequence.
    See page 2, "New Cam Sensor Type": https://documents.holley.com/techlib...140updates.zip (Holley EFI Updates for V5 version Build 140)
    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, 232°-244° duration/.623" lift/114° LSA camshaft, 11.8:1 comp, TFS R-Series FTI ported intake, BBK 80mm TB, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 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, B&M Hammer shifter, 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.

  10. #10

    Default

    Quote Originally Posted by fastmanefi View Post
    Once the customer changed the wiring per Danny's notes, and he changed to Digital Falling, the system now acts as you'd expect. Thanks for your help Danny.
    No drop out after the start and the cam sensor is now very aware of it's position. What I did not know is that the algorithm will switch to waste-fire with a missing tooth type crank trigger if the cam signal faults. That's why it appeared to not care, but it does. More to follow after I scope injector signals and do a System Log.
    That is definitely strange and not expected behavior. But it does explain a few things.

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