From my understanding the air pump is just that. The air pump pumps air into the exhaust to enhance burning of unburnt combustion. How can the air pump "heat" up the exhaust?

I believe the theory is that the exhaust burns some of the unburnt vapor, thus sending more of of CO2 and H20 otherwise.

I think your first assessment made more sense, could be wrong though.



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'89 420 SEL
'90 300 SEL
'68 Olds 88 Convertible
'84 300 SD (sold it)