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Thread: Mallory Hyfire 6AL Tach Sweep

  1. #1

    Default Mallory Hyfire 6AL Tach Sweep

    I'm installing a Holley Sniper EFI and HyperSpark Distributor, but keeping my Mallory 6AL and Mallory Promaster Coil. I have been reading through all of the instructions to get as familiar with the install as I can before I start this project, and I noticed a highlighted comment that if your CD box does a tach sweep that it needs to be disabled or there is a chance it could flood the Sniper. I have a Mallory HyFire 6AL model 6853M. Every time you turn the key on the tach does a sweep of the entire RPM range from 0 to 8000 and then returns. I have looked everywhere for the procedure to turn this off and I cannot find it anywhere. I found the one for the MSD where you ground the gray tach wire with the key on for 5 seconds, not to exceed 10 seconds, and that toggles between off and on, but nothing on the Mallory. Does anyone know how to turn this off or if it's even possible to turn it off, or maybe the Mallory does not do a tach sweep?

    It could also be the tach itself doing a test. It's an in-dash tach designed to look like a Rally Tach in a '65 Pontiac GTO, but it has more modern electronics in it and runs fine off of the yellow tach wire from the Mallory CD box. I have read other threads on the Pontiac Forum where people complain these new tachs do a sweep every time you turn on the key. So I'm trying to find out if the tach sweep is being caused by the Mallory CD box or the tach itself. Since the owner's manual for the Mallory CD box does not mention a tach sweep I'm hoping it's just the new tach. Thanks for the help, Dale

  2. #2
    Join Date
    Dec 2009


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  3. #3


    I thought that there might be people out there with the same Mallory 6AL that would have first hand knowledge of weather or not this box has the tach sweep option. There is absolutely no information on the internet concerning this and I would like to know before I get it all hooked up and try to start it. Because, if the Mallory does do a tach sweep, and it cannot be turned off, then I will need to buy the HyperSpark Ignition. I'm starting to think it might not be the CD box and might be the tach itself. Dale

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