DIY_EFI Digest V5 #89

[dzorde at erggroup.com]

Thanks all who replied, I suspected it was P/H style injector.  I'll and have a
look at the 332 driver board circuit.  The use of the resistor still has me
wondering though, Nissan (I think) used to have resistors in series with the
injectors, were they low impedance injectors ?  What value was the resistor (5R,
10R) ?

Dan  dzorde at erggroup.com

>Date: Tue, 7 Mar 2000 06:12:07 -0800
>From: "John Dammeyer" <johnd at autoartisans.com>
>Subject: Re: Subaru TBI
>
>
>Yikes!  or How to screw up an injector in one easy pulse.
>
>This is a PeakHold type injector.  13.8V / 1.6 Ohms is almost 9 Amps.
Injectors normally
>don't take more than about 1A.  You have a choice on how to drive a PH
injector.  You can
>place a Ballast resistor in series to limit the current to about 1A.  This has
the effect
>of driving the injector hard until the current through the resistor is high
enough to
>reduce the voltage across the injector and therefore limit the current.  You
still end up
>with a fast turn on time.  Alternatively you can use a PH type injector driver
or a
>circuit with a comparator and a current sensing resistor (0.1 Ohm) that reduces
the
>current once it reaches 1A or a timer based driver that reduces the current
after n
>microseconds which is equivalent to the time it takes for the injector current
to reach
>1A.
>
>Only if the injector resistance is around 12 Ohms can you apply 12 volts
directly to it.
>
>John Dammeyer




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