measuring hall output

[auditude at neta.com]

Konstantin Bogach konstantin.bogach at morganstanley.com wrote:
>
> Hall sensor   produce different output voltage for different strength
> of magnetic field.  Audi's sensor has 2 parts: hall sensor and magnet.
> The metal cup in distributor has openings. When cup's metal wall
> blocks magnetic field from magnet (inward part of sensor) the output
> ~5V, when opening passes through sensor the sonsoring part is under
> magnetic field and voltage changes to ~0.5V. If you manually rotate
> crank you can measure the signal with voltmeter.

This is what I was wondering, and even discussed with Marc S. the
idea of using a voltmeter and manually turning the motor.

That would get me one part of the measurement that I need, the
other part is where the edges are relative to the crank position.

Hence, my question about if I can just calculate the position, by
telling the ecu vendor that the falling edge is 20 degrees ahead of
62 btdc, and the rising edge is 20 degrees after 62 btdc.

(Part of the reason I've been in no hurry to put my 5kcstq back
together is in case it's easier to take any readings off of it while it's
apart.  It'd be easier to measure that motor in situ than messing
with the donor motor on the stand, and hooking up power to the
hall sensor, etc.)

> Pull the boot off the
> connector to get access to bare contacts (while it is connected) and
> measure voltage across  right most and central contacts when ignition
> is on (don't start engine, disconnect central wire from distributor
> for prevent from accidental starting).

Thank you very much for this information!

> With engine running you can use low voltage LED tester. If signal is
> ok it will blink.

I've been afraid to proceed with measuring things for fear of
damaging something.  I'm a bit gun-shy about the hall sensor,
because remember a friend having to replace one after damaging it
by checking for spark improperly, iirc. (not grounding the plug body
can fry it?)

Someone else confirmed that I can measure the output with a
meter, since the inputs are high impedance.

> > If anyone has the ability to measure the output of the hall
> > sensor, and is willing to do so, will you please contact me or
> > post to the list?  Maybe that's what I should ask?
>
> Konstantin Bogach.
> P.S. Sorry, I don't  know Ken's e-mail.  I missed original post.

Thanks Konstantin!

Ken