A question for you engineering types:
I'm thinking about monitoring my A/F ratio to try to keep my car from
holing pistons at inopportune moments. I've read up on the limitations
of using the cheap 3-wire O2 sensors and the relatively inexpensive
LED-segment or needle swinging processor gauges (total cost maybe $50)
vs. using a UEGO sensor and 0-to-1.0 volt digital read out display
(total cost $250-500). Keeping in mind: no ECU to control, no turbo, no
fuel injection...just Mr. Skinner's wildly exotic array of metering
needle profiles to choose from. The issue that I've read about
repeatedly is that the older narrow-band sensor samples a more or less
binary output and averages the voltage to light up the appropriate
number of LEDs on the gauge. This is non-linear and so only tells you
are you "on the rich side", "on the lean side", or stoichiometric. It's
also criticized for being too slow in its response. The UEGO-volt meter
set-up is more precise and can give you an actual A/F ratio to look at
more or less instantaneously.
So...since I don't have to control any electronic engine management
systems, do I need to know more than "too lean", "too rich," "just
right" to diagnose high exhaust gas temp issues or to select the best
needle profile for a modified motor?
I am trusting you guys with my money, so advise me wisely!
-JohnD
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