injector on/off ratio display

Discussion in 'General Motoring' started by r2000swler, Jun 18, 2005.

  1. r2000swler

    r2000swler Guest

    For over a year now I have been trying to find a design
    for a, for lack of a better term, "FI on dwell time
    indicator".

    My Civic has 2 injectors, main and aux. So I decided
    to use a WWII surplus dual meter that I have had "
    forever". I used a 1N4004 and a 5K resistor to isolate
    each meter from the ECM/FI. I add a capacitor to integrate
    the pulse width and have a "simple" meter that shows me
    how long each injector is open. In the 4 FI engines I
    would just monitor oninjector because (I think) they
    "should" all be pretty much the same.
    I had to use a 5uF for the primary and a 20uF for aux.
    This morning it was 46F when I left for work and for the
    first ~2 minutes the aux was hihger then I had ever seen
    it before. The aux is mainly used during acceleration and
    starting. I initially used a laptop with a dataq data
    logger, but soon found out you can't drive and read a
    display!

    These values can't be calculated, because it depends on the
    meter sensitivity, internal resistance and needle ballistics.
    And inches/mm of vacuum doesn't really correlate with injector
    on time very much at all. At times you get the best, least,
    injector on time with vacuum a lot lower then I would have
    thought. I am debating trying to rig a voltage controlled
    oscillator with the primary and try to learn to drive with
    the lowest tone.

    The 10K parallel resitance across the injector will draw a
    miniscle additional current. 15V/10K=1.5mA. I used 15v
    because it is the highest the eninge should ever see.

    Given the constantly climbing cost of fuel, I am after any
    sane way to reduce my costs.

    Does anyone have a link to one of the hot rodders who might
    have mapped out the temp/speed/RPM injector timming?

    Terry
     
    r2000swler, Jun 18, 2005
    #1
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