[mkiv] Injector Duty Cycle Monitoring (ODBII)

[Chris Romano]

Thanks Grant, I'm going to back off a bit so that the
car will put down 530 to 550RWHP.
With the propane the car's fuel system will be able to
support that with no problem.

Thanks!

-Chris

--- Grant Beaty <gbeaty at ufl.edu> wrote:
> Low impedance injectors aren't a square wave, it has
> a peak, then a "hold"
> at a lower voltage, since it takes less volts to
> hold the injector open.
> Thats why I suggested using a voltage regulator to
> "cap" the voltage off to
> a certain value, which should transform it into a
> square wave (Assuming the
> regulator works ideally).
> 
> All the multimeters I've used have a built in
> capacitor on the voltmeter
> part. 50% duty cycle on my E Manage's injector
> driver (which IS a square
> wave) shows up as 6v, 100% shows up as 12v, etc.
> 
> Grant
> 
> ----- Original Message -----
> From: "Dan" <jiggersplat at hotmail.com>
> To: <mkiv at mkiv.com>
> Sent: Thursday, April 24, 2003 2:00 PM
> Subject: Fwd: Re: [mkiv] Injector Duty Cycle
> Monitoring (ODBII)
> 
> 
> > the injectors use a pulse width modulated signal. 
> what this means is
> > you get a square wave from 0 to whatever volts the
> injectors use.
> > say the freqeuncy of the wave is 1Hz or one cycle
> per second.  a 50%
> > duty cycle means that for that one cycle (one
> second) 50% of the time
> > the voltage level is high, the other 50% it's low.
>  in general, this
> > is how digital computers can control analog
> devices without an A/D
> > converter.
> >
> > if you really wanted to use a multimeter, it is
> possible to design a
> > circuit to convert a PWM signal into a voltage
> level.  you need to
> > know the frequency of the PWM signal and you can
> select a properly
> > sized capacitor and resistor.  there is however
> some latency to
> > this.  it may take a few cycles before the voltage
> level accurately
> > reflects the pwm signal.  a properly designed
> circouit should
> > minimize the delay.
> >
> > dan
> >
> > --- In mkiv at yahoogroups.com, "Grant Beaty"
> <gbeaty at u...> wrote:
> > OBD2 cannot display duty cycle on Toyotas.
> >
> > A multimeter won't wort too great, since its a
> peak-hold signal. The
> > voltage
> > spikes them drops down. Maybe if you used a 1v
> regulator to cut the
> > voltage
> > off and make it a square wave, the multimeter
> could read 0-1v for 0-
> > 100%
> > duty cycle. Thats just a guess though. It probably
> depends on your
> > multimeter, I think most have a capacitor in the
> circuit somewhere
> > anyways.
> >
> > Grant
> >
> > ----- Original Message -----
> > From: "Chris Romano" <c_romano at y...>
> > To: <mkiv at m...>
> > Sent: Thursday, April 24, 2003 12:23 PM
> > Subject: [mkiv] Injector Duty Cycle Monitoring
> (ODBII)
> >
> >
> > > Is there a way to monitor the injector duty
> cycle?
> > > Are there any connections where a multimeter can
> be
> > > used to monitor voltage which may indicate
> injector
> > > duty cycle percentages?
> > > Just curious...I need to get some numbers on
> exactly
> > > what is going on with my injectors and where
> they are
> > > at.
> > >
> > > Thanks,
> > > Chris
> > >
> > >
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