Quad-4 (1228707 ECM) Rough Idle Problem

[Shannen Durphey]

Hold on....  Tell me again how you checked timing, and what your
results were?  On the dizzy equipped 4 cyls, GM wants the timing light
connected to the coil wire so it flashes with every plug firing, and
the timing is set by the "averaging" method, a service manual way of
saying "a good guess".  The timing can really fluctuate on some of
those older engines, and I know that trying to time by #1 alone gives
bad results.
Shannen

Will Remaklus wrote:

> I also tried disconnecting the EST output from the ECM such that
> the ignition module controls the timing: no difference.
>
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