measuring hall output

auditude at auditude at
Mon Feb 25 15:40:26 EST 2002

Hi Konstantin,

Thanks for the tip on the replacement.  I think another lister
mentioned that the hall sensor guts were available from an unusual
source, whereas they are normally unavailable separate from the
distributor.  Unless I don't remember correctly.

My biggest "challenge" with doing this is that I don't have much in
the way of jumpers and testing leads.  It seems like the best way
to do it is to connect the hall sensor to the harness with some kind
of connector that leaves access to one or all of the contacts so
that I can tap in in parallel.

I got a multimeter to use, but it was so beautiful outside this
weekend I never got under the hood to get started.  However, I did
find the Bentley page on the matter.  That and the helpful posts
from here and the 'net have increased my understanding of how it
works immensely.

I think the procedure will be to pull the plugs, ground the high
tension coil lead, reconnect the battery (isolate the loose starter
wire first, tranny's still out), connect the meter, and turn the motor
over.  Oh, I have to replace the flywheel (read: rear oil seal and pilot
too), in order to get the extra point of reference for the crank

However this I will doing only to confirm how wide the "window" is
of the hall output.  I won't be using it for an exact reference relative
to tdc, since the distributor is adjustable.  Unless the distributor is
way out of spec (indexing) from where I expect it, I will go with the
82 btdc spec for the leading/falling edge of the sensor output.
(trying to get these specs for a sync trigger for an efi ecu)



On 25 Feb 2002, at 15:57, Konstantin Bogach wrote:

> I can not answer this question but here is a cheap way to replace it:
> $10-20  for used distibutor in junk yard. Audis of '86-91.  You can
> take it apart and use hall sensor as a donor.  They might look a
> little differently (open magnet or inside the plastic body) but will
> work.
> Konstantin Bogach.
> > From: auditude at
> >
> > 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?)
> >
> > Ken

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