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Thread: Regarding the Minimum Signal Voltage

  1. #1
    Join Date
    Oct 2016
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    Middle River, MD
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    Default Regarding the Minimum Signal Voltage

    How would we know if we've raised that setting too high? Mine was at .35V and still kind of kicked back every 3rd start or so. I raised it to .60V, but it didn't really seem to help. Does lowering that minimum cranking RPM change how quickly, or easily, it will crank? Battery is fine, load tested it. Doesn't seem to matter if it's hot or cold, engine-wise. Not sure what else to look at.

  2. #2
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    Quote Originally Posted by rel3rd View Post
    How would we know if we've raised that setting too high? Mine was at .35V and still kind of kicked back every 3rd start or so. I raised it to .60V, but it didn't really seem to help.
    It involves the hassle of reading a System Log and its "Crank A/D" channel to determine the optimum value.
    That's the problem with using VR Magnetic sensors, there's more tuning work. Hall-Effect is "set & forget".
    The VR Magnetic Sensor Type "Minimum Signal Voltage" & "Filtering" parameters need to be programmed.
    http://documents.holley.com/199r10676rev.pdf (Magnetic Crank/Cam Input Filtering Parameters, Page 2)
    http://forums.holley.com/showthread....4450#post54450 (Example: Wrong Magnetic Parameters, Post #25)
    EDIT: The Sniper EFI isn't capable of recording System Logs.

    Quote Originally Posted by rel3rd View Post
    Does lowering that minimum cranking RPM change how quickly, or easily, it will crank?
    If you're referring to the "Crank To Run RPM" parameter, I've never had to change it from 400 RPM.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  3. #3
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    Oct 2016
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    Quote Originally Posted by Danny Cabral View Post
    That's the problem with using VR Magnetic sensors, there's more tuning work. Hall-Effect is "set & forget".
    I don't understand why it was fine for a while, now hard starting.

    I just went online looking for one (LINK), and again, they aren't available through HOLLEY, or any of the big stores.
    Click image for larger version. 

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    Last edited by rel3rd; 05-26-2017 at 09:00 AM.

  4. #4
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    Palm Bay, FL
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    Raising the MSV absolutely can affect how well it starts. Particularly if the engine cranks slowly (low battery or high compression engines).
    The VR/Magnetic pickup induces voltage as the reluctor passes the magnet. How much is induced is directly proportional to the speed at which the reluctor is spinning.
    So at cranking speeds, it's generating a very low signal. If the MSV is higher than the voltage that is being inducted then the engine never sees the crank signal.
    You might try backing up to .30V and then .25V to see if that helps. If you've set the Filtering to High, you might try setting it to Low.
    Chris Myer
    800-880-0960 x654
    chris@EFISystemPro.com

    Check our www.EFISystemPro.com website for live stock status on
    all Holley items, including the full line of Holley HyperSpark Distributors!

  5. #5
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    Oct 2016
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    Middle River, MD
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    It's kicking back on the starter, like if the car had mechanical timing, that was too far advanced. Actually has screwed up 2 starters now. No difference found in setting MSV at the default 0V, .35V, or .50V.

    I love the way my car idles and runs with Timing Control, but I'm very seriously considering swapping it back to mechanical timing and be done with all the BS related to MSD/Timing Control. My car will easily crank and start with 44° of LOCKED Timing, but not with a supposed 15° cranking timing, which I also tried lowering with absolutely no effect.

    It used to start immediately, PRIOR TO TIMING CONTROL, but now wants to crank over a good bit, and then it will kickback and booger up the starter drive gear. That was why I had asked about changing the Crank RPM to Start setting from it's 400 RPM default.
    Last edited by rel3rd; 05-26-2017 at 11:45 AM.

  6. #6

    Default

    Quote Originally Posted by rel3rd View Post
    I don't understand why it was fine for a while, now hard starting.

    I just went online looking for one (LINK), and again, they aren't available through HOLLEY, or any of the big stores.
    Click image for larger version. 

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    I noticed they were out of stock when I talked to Holley. I bought the last one EFI System Pro had but maybe they will sell you the one I shipped back with the gear on upside down. LOL.
    EDIT: You are out of stock despite your showing in stock correct Chris? http://www.efisystempro.com/dual-syn...scription=true

  7. #7
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    Uh Oh. Chris told me 2 hours ago that he had exactly ONE LEFT in stock, so I bought it, and it was supposed to be shipping out today, or so I hope. Was your upside down one from Holley, or EFI System Pro?

  8. #8

    Default

    Rel3rd, I remember you chimed in on my initial MSD setup thread, and it still appears we're having similar issues with the system. Although my engine is not kicking back. It sounds like you're going to be ditching the MSD for the Holley distributor. For the time being, I'm trying to make mine work, but these threads that keep popping up are making me lose any long term confidence that the MSD setup will continue to work.

  9. #9

    Default

    I bought an MSD distributor using a discount Holley gave me for being so late on the Sniper EFI last year. It seems simpler & cheaper to use the MSD. But...add the price of a 50 mile ride on a flatbed along with the MSD price, and maybe the reliability of a Dual Sync distributor is worth it.

  10. #10

    Default

    Precisely my thoughts. While I may be able to get my MSD setup to "work", a $300+ tow bill when I can't get it going again on the side of the road would go a long ways towards a Dual Sync distributor. But then again, the user who was having trouble with the air cleaner states they tried one and still had the issue. So I wonder if even the Dual Sync distributor would truly be a fix?

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