Timer circuit mayhem!

Discussion in 'The Projects Forum' started by nmracer, Sep 11, 2011.

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  1. nmracer

    Thread Starter New Member

    Sep 11, 2011
    I am attempting to create a very basic circuit to automatically control the fuel system changeover on a vehicle. Essentially, I am trying to start two timers once the ignition is shut off in order to delay the actual engine shut off. In other words, once ignition is off pump 1 runs for another 2 seconds and pump 3 runs for an additional 60 seconds.

    Currently I am attempting to hook up two 555 timers but I am not sure if I am understanding the theory correctly. My idea was to hook up the ignition to pin 6 in order to start the timer once voltage was removed and have the output turn on a relay to the appropriate pump for the duration. However, it has come to my attention that the input signal needs to be shorter duration than the output? Does this mean I am unable to use a 555 for this project?
  2. Bernard


    Aug 7, 2008
    See Bill Marsdens blog on 555 timers.
  3. magnet18

    Senior Member

    Dec 22, 2010
    sorry, but car mods are off-limits here for legal reasons
  4. bertus


    Apr 5, 2008

    I am closing this thread as it violates AAC policy and/or safety issues.

    6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

    • Any kind of over-unity devices and systems
    • Automotive modifications
    • Devices designed to electrocute or shock another person
    • LEDs to mains
    • Phone jammers
    • Rail guns and high-energy projectile devices
    • Transformer-less power supplies
    This comes from our Tos:
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    There will be enough sites where automotive questions can be discussed :
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