Troubling symptom on initial startup last night...

Discussion in 'PSI Superchargers Tech Questions' started by Scouder, Apr 16, 2011.

  1. Scouder

    Scouder New Member

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    I run an 8973 (with no problems) and the suggested capacitor. Since the 8973 kills the engine when not powered up, I wired the car over the winter to use a "bomb release" switch on the steering wheel to kill power to the entire car.

    Last night I had my high school kids over. The local high school has given me a couple of their smarter kids to work on the car, and it counts as their auto shop credit. Anyway, we did the first startup of the year last night. All went very well until time to shut the engine off. I killed the fuel, and when she revved up I slapped the bomber switch closed and it kept running! It took about 1 second, or maybe 1.5, to shut off. Since I have the capacitor wired in right before the 8973, and after the switch, I suspect it is holding the ignition system up.

    I will be re-wiring to put the capacitor out of reach of the 8973 when the switch is closed and post if that is the solution.

    Just a heads up if any of you intend to use the 8973 as your kill switch.

    -Brian
     
    #1
    Scouder, Apr 16, 2011
  2. Mike Canter

    Mike Canter Top Dragster
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    Well that tested out the capacitor. Ya got the switch in before the capacitor, it is meant to be after the capacitor. It is doing just what it was designed to do:rolleyes:
     
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    Mike Canter, Apr 16, 2011
  3. Dave Germain

    Dave Germain New Member

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    bomb release switch?

    Whats a bomb release switch? I am looking for a switch for my racepak that would keep it from getting accidently switched on or off. As you guys know after a run if you turn it back on you lose your data. Anybody have an idea how to make it more difficult to accidently switch back on after a run? Dave Germain
     
    #3
    Dave Germain, Apr 17, 2011
  4. Mike Canter

    Mike Canter Top Dragster
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    It is really called an aircraft switch guard for any toggle switch. They are spring loaded and will turn the toggle switch off when closed. We have one to shut the mag off that is on a panel from a roof bar. They are easy to hit and turn off when wearing gloves and whe the guard is closed the car cannot be started.

    In a lot of WWII movies you always see the bombardier lift the cover and hit the switch to drop the bombs.

    Check them out here but you can find them at Jegs or Summit also.
    http://www.aircraftspruce.com/menus/el/switches_zaccessories.html

    You could turn the toggle switch 180* so it was locked on with the cover closed for the Racepak. The other switch that would be could for you is one where the toggle has to be pulled out to get over a ramp to turn on or off. http://www.amazon.com/Micro-Switch-4TL1-2D-Sealed-Locking/dp/B000PDJSVE
     
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    Last edited: Apr 17, 2011
    Mike Canter, Apr 17, 2011
  5. Scouder

    Scouder New Member

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    I want to make sure I'm on the right page here.

    The purpose of the capacitor is to hold the system up in the event of a power interruption of some sort? Like a sagging battery or loose wire between the battery and the retard box?

    The reason I ask is because if that's it's only purpose, then any connection between it and the retard box introduces another point of potential failure, making it less likely to be effective. No?

    -Brian
     
    #5
    Last edited: Apr 17, 2011
    Scouder, Apr 17, 2011
  6. Mike Canter

    Mike Canter Top Dragster
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    The retard box power should be connected to the capacitor aswell. The other purpose of the capacitor is to eliminate voltage spikes and noise riding on the 12 v DC that can damage or upset the MSD units
     
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    Mike Canter, Apr 17, 2011
  7. Scouder

    Scouder New Member

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    Well, my system is very simple. Battery to bomber switch to terminal strip. Terminal strip to everything else including capacitor and 8973. The only way to prevent run-on from the capacitor is to put the capacitor between the battery and the bomber switch. Then it would be battery to capacitor to bomber switch to terminal strip to 8973.

    Any problem with that?

    -Brian
     
    #7
    Scouder, Apr 17, 2011
  8. Mike Canter

    Mike Canter Top Dragster
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    No problem
     
    #8
    Mike Canter, Apr 18, 2011
  9. Scouder

    Scouder New Member

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    Thanks Mike. The high school kids are back tonite, so we'll start re-wiring. I gotta hand it to these kids. They are on spring break this week, but wanted to keep coming to the shop anyway to get the car ready.

    -Brian
     
    #9
    Scouder, Apr 18, 2011

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