1984 4k - no start

urq urq at pacbell.net
Wed Aug 5 12:57:46 PDT 2009

Brett was proposing repair of the Hall Sensor plate already in the
distributor.  I've never had a need to do this as yet in any of my cars, but
for someone who is handy and a little bit familiar with Hall Effect devices,
it should be possible to repair a faulty distributor Hall Effect Sensor
plate for only a few bucks.

I would suspect that there is some BTDT on the list and from that you might
be able to gain information about devices that will work for this
application.  If you were lucky you might even find the manufacturer's part
number on the part in the distributor, which would give you a good head
start on determining a replacement.  While Hall Sensors use the same
property of electron movement in a semiconductor when a magnetic field is
applied, there are several varieties of sensors out there, you're not going
to be able to walk into Radio Shack and see something that looks exactly
like the part in the dizzy ... 

All that said ... before taking the dizzy apart I would strongly support the
suggestion to first verify that the supply and ground voltages are present
(if not, find and fix the supply problem).  Once the power is confirmed,
pull the distributor and verify that the Hall Sensor switches between ground
and 5 volts as the dizzy shaft is rotated slowly.  If all this passes
there's no need to look any further into a problem with the Hall Sender in
the dizzy.  

Another source of problems with the Hall Senders on the distributor is that
the wires that connect to the Hall Sender in the distributor come into
contact with a moving part inside the dizzy and are disconnected.  The
connector that mounts to the side of the distributor is not robustly mounted
and can come loose if too much force is applied ... this may reposition the
wires to the Hall Sender which are then damaged ... 

Steve Buchholz

-----Original Message-----

Brett Dikeman wrote:
> On Tue, Aug 4, 2009 at 11:01 AM, Bares,
> Vittorio<Vittorio.Bares at nuance.com> wrote:
>> Have not tested the coil but have swapped it w/a new one.
>> Parts supplier is telling me $175 for the hall sensor assembly. :o
> If you can pull it apart, the hall sensor component itself costs a few
> dollars at most.  They all work just about the same way.
> -Brett
"A few dollars at most"?  List is $165, and I doubt you'll find one for 
much under a hundred bucks.    John

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