Pertronix diagnostic tip 2cyl
Posted: Thu Aug 11, 2016 2:14 pm
So I came across a weird one, may shed light for others. Upon installing a new unit, the engine would not start(no spark). Since I have never found a defective module I decided to investigate before writing it off as bad. First off the Pertronix unit is 2 parts, module and pole piece.
The pole piece(trigger) contains 4 small magnets, the magnets are arranged by pole position(North or South).
I started by testing a known good module(on my Haflinger), as they tested alike next step was testing the ring. As soon as the ring was swapped with mine, it sparked fine and started. Next the new pole piece was tested on my Haf and it would not produce a spark, so after some thought on how this sensor makes a signal, a compasswas the correct diagnostic aid.
Using the compass on a flat surface, I rotated the ring next to it notating magnetic direction. The ring that worked was oriented (bottom view), flats to right and left starting upper left and then clockwise, North, South, North, South.
The ring that would not work had all four magnets North facing.
It was an easy fix(used thin blade at bottom of ring to pop retainer loose, re-orient magnets and super glue retainer).
Of note, I can see how easy it is to make this mistake in small batch manufacture as four cylinder pole piece have all four facing North and it is the same plastic housing with a modified lobe mount bore.
Been swamped with heavy work, more posts as soon as I get caught up
The pole piece(trigger) contains 4 small magnets, the magnets are arranged by pole position(North or South).
I started by testing a known good module(on my Haflinger), as they tested alike next step was testing the ring. As soon as the ring was swapped with mine, it sparked fine and started. Next the new pole piece was tested on my Haf and it would not produce a spark, so after some thought on how this sensor makes a signal, a compasswas the correct diagnostic aid.
Using the compass on a flat surface, I rotated the ring next to it notating magnetic direction. The ring that worked was oriented (bottom view), flats to right and left starting upper left and then clockwise, North, South, North, South.
The ring that would not work had all four magnets North facing.
It was an easy fix(used thin blade at bottom of ring to pop retainer loose, re-orient magnets and super glue retainer).
Of note, I can see how easy it is to make this mistake in small batch manufacture as four cylinder pole piece have all four facing North and it is the same plastic housing with a modified lobe mount bore.
Been swamped with heavy work, more posts as soon as I get caught up