86 4kq mixture adjustment problem

[Lino M. Valadas]

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Hello all 4kq owners,

I was in the process of adjusting the O2/fuel ratio using a dwell/tach meter
connected to the two prong plug by the battery which I've used several times
for this purpose, when it suddenly stop responding.   The plug is not dead
but it dropped from the usual reading of about 36 to 40 on dwell scale to
about 1 or 2.
Does anybody know what could have caused this sudden drop.  I have looked
everywhere for a bad connection to no avail.  I'm still not getting a
reading.

TIA and a Merry Christmas

Lino

83 Ur-q
93 S4 (fading out)

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