[Diy_efi] false myths

[Michael Richards]

> "AFAIC, misfire from too lean an A/F mixture, is a false myth.  In

Let's call a lean misfire one where a mixture experiences an incomplete 
combustion as a result of it's average fuel to air ratio. For a false 
myth you will find a large number of articles if you google search 
for "lean misfire".

> reality, continual leaning can be conducted until which time, the
> combustion flame, due to a lack of heat, just goes out.  Sorta like
> turning down the gas valve on a kitchen range, less and less heat (not
> more) is generated until the flame, from a lack of fuel finally goes

This is in fact nothing like turning down a gas range. As you turn down 
the gas range the quantity of fuel and air at the burner is reduced. 
This is similar to closing the throttle on a car while maintaining the 
correct mixture. 

> out.  The misdiagnosed so labeled 'misfire' is actually the result of
> the flame in one or more cylinders going out ahead of the others, due
> to the normal lack of a precise equal AFR in all cylinders.  The
> physical appearance/feeling of a misfire, is actually in reality, one
> or more cylinders going dead, no different than if a plug suddenly
> stopped firing."

I really wonder where you got this info. I would say it's flat out 
wrong. Your explaination of it as being a "normal lack of a precise 
equal AFR in all cylinders" would imply that there is a magical point 
in the mixture where the cylinder ceases to fire. After all, if it's a 
point where it's no different than if a plug "suddenly stopped firing" 
then you're saying there is either a complete combustion event or not.

If this is the case then what happens without a uniform mixture? If the 
spot near the plug is rich enough to be ignited normally and the rest 
is not wouldn't it by your definition result in a lean misfire? 

-Michael
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