Characterization of products of non-stoichiometric combustion

To give some background, I'm looking at this from an aerospace standpoint as to the calculation of the efficiency of a propellant reaction at a given oxidizer-fuel ratio. That efficiency is a prerequisite to obtaining other results such as the adiabatic flame temperature, the specific impulse ($I\_{sp}$) and other such data. 


How is it that the relative abundances of products can be obtained from a non-stoichiometric combustion in an analytic manner (i.e. without needing to obtain empirical data)? This is particularly important because rocket engines rarely run stoichiometric, due to exhaust considerastions.


From the [Wikipedia article on combustion](https://en.wikipedia.org/wiki/Combustion#Incomplete_combustion_of_a_hydrocarbon_in_oxygen), it shows that incomplete combustion results in primarily carbon dioxide, carbon monoxide, water and elemental hydrogen gas. However, it also states that:



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> For stoichiometric (complete) combustion, $z = x + ¼y$. When $z$ falls below roughly 50% of the stoichiometric value, $\ce{CH4}$ can become an important combustion product; when $z$ falls below roughly 35% of the stoichiometric value, elemental carbon may become stable.
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This makes sense, as anyone who has left the barrel of a lit Bunsen burner shut has seen the sooty smoke it produces; but is there a manner in which these products may be analytically identified (and quantified)?


To cover all bases, I've had some experience with the use of NASA's [CEA program](http://www.grc.nasa.gov/WWW/CEAWeb/ceaWhat.htm), and it appears to have some ability to calculate thermodynamic parameters of propellants that aren't given as choices (i.e. RP-1, $\ce{H2}$, etc.). I've read the manual on its theory of operation, but I'd like a more gentle introduction to the underlying behavior, if at all possible.


