[DML] Re: Great Stopped Up Catalytic Converter Debate

["David Teitelbaum" <jtrealty@xxxxxxxxxxx>]

The "smog pump", aka air injection pump, was necessary on the older
carbureated cars because they had so much unburned hydrocarbons that
they needed additional oxygen to burn all the hydrocarbons in the
exhaust (especally when in the warm-up cycle). In fact the air pump
was on many cars even before the catalytic converters. It had the dual
purpose of adding more oxygen so the hot unburned gases could continue
to burn in the exhaust system and it also helped to dilute the exhaust
thereby "lowering" the tailpipe emissions. It isn't used on the
Delorean because the exhaust is already very low in hydrocarbons so
the introduction of additional oxygen isn't required to burn the "left
over" hydrocarbons. Besides, putting the pump on only reduces the
horsepower available to move the car, increases the cost and weight of
the car and adds the complexity of another system. I don't know of any
fuel injected car that has an air pump with a catalytic converter. The
fact is the Delorean runs so clean that it doesn't even need an
exhaust gas recirculation system. Of course it does need to be
maintained to keep it running well. One fouled spark plug or dirty
fuel injector can mess the whole thing up. A catalytic converter will
glow red only because it is burning too much unburned fuel. Think
about it, what can cause it to get hotter than the rest of the exhaust
system, only if it is burning something inside. A too lean condition
can't do that. A glowing red converter is a sign that unburned fuel is
getting to it from the motor usually because a cylinder is misfiring
but also if the mixture screw is set too rich. A cylinder can misfire
for many reasons including; a bad/fouled spark plug, a bad ignition
wire, a burnt valve, broken ring, blown head gasket, valves way out of
adjustment, leaking, dirty fuel injector to name a few.
David Teitelbaum
vin 10757 


--- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@xxxx> wrote:
> Re: side by side Messages #39435 and #39436:
> 
> The great "catalytic converter stops up because mixture is too rich"
> vs "catalytic converter stops up because mixture is too lean" debate.
> Fuel mixture may have nothing to do with it:
> 





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