Re: Ignition Redundancy

[jlandry@domain.elided (John A. Landry)]

As the putrid festering facial boil erupted, Darrel Kline
<darrelk@domain.elided> yelled:

>>>How do
>>>they get real time advance from one spark signal? I know that RPM is
>>>just a formula based on the number and frequency of plug firing.
>
>How would the analyzer be able to determine the position of the piston from
>the spark plug wire signal or exhaust gases?

Unless some piece of test equipment new the position of the crankshaft at
any given time (not possible from the spark), then it doesn't seem possible
to know the degree of ignition advance.  How in the world could the testing
machine tell the difference between the spark pulses changing because of
advance verses increased rpm.

However, *maybe* the testing machine creates some sort of a base line
reference at idle and assumes this is some amount of advance.  If the spark
pulses come closer together, this means the rpm is increasing.  If the
spark pulses move forward or backward in time, this could mean advance or
retard.

Tom H... are you sure the testing machine monitors advance?  Why do they
care what the advance is during the test.  I can see why they might want to
know rpm in order to calculate road speed (??), but why advance?

John
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