Re: Ignition Redundancy

[Tom Harais <tjhemh@domain.elided>]

John:

Probably not as far fetched as it might seem. Those of us subject to
smog inspecitons have been amazed at the machines they use. And, because
they keep uping the requirements, the older, obsolete machines are for
sale for a few hundred dollars all the time.

One of the features that amazes me is, they put a "sniffer" in your
tailpipe and a inductive clamp on your #1 cylinder wire. From this
alone, these machines will give you engine RPM, real time ignition
advance, and of course, HC PPM, CO PPM , NOx PPM, CO2% and O2%. 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.

Tom H.