The Importance of Warming Your Vehicle Even when it's cold outside, modern
engines don't stay cold inside for very long. A wise man once said you can't
teach old habit new tricks before it dies hard. Or something along those lines.
In the early days of the automobile, owners did well to get their cars running
after a dozen attempts, and keeps it running for as many minutes -- and that was
on the best of days. Times have changed quite a bit since then, and so have the
ways we maintain and drive our cars. Have a question? Get an answer from a
mechanic now!Basic Warming Back when even the best cars on the road ran on
metered fuel leaks -- aka "carburetors" -- automobiles had a difficult time
running while cold autel
maxisys. Engines are designed to run at a certain temperature, usually
around the boiling point of water. Much above or below that temperature, and the
engine loses combustion efficiency and fails to turn the fuel going in into
horsepower. Carburetors got around this problem using a choke, which limited
airflow and proportionately increased the amount of fuel in the mix. The choke
had to stay closed until the car warmed up and combustion efficiency came back
up to level. By that time, the engine's metal had expanded to where it needed to
be, and all the fluids were warm and circulating. Unfortunately, carbureted cars
were often so cantankerous during the warm-up period that they were all but
undriveable for several minutes -- hence, the need for a considerable warm-up
period before setting Converter Light-Off Prior to catalytic converters, few
people really thought about warm-up procedures provided that the car eventually
warmed up while idling. However, things changed drastically from the factory
perspective when cats debuted. A catalytic converter works like a chemically
enhanced furnace, burning off unburned fuel before it escapes from the exhaust
pipe. To do that, the converter matrix has to reach a certain temperature --
usually about 800 degrees Fahrenheit. This "light-off" took a long time on
carbureted cars, because the presence of extra fuel in the mix via the choke
lowered combustion temperature, which ironically made the converter take that
much longer to light off. Over a few years of raw fuel pouring through for
several minutes without light-off, impurities in the fuel would clog and
"poison" the Cars Things changed drastically after the introduction of
electronic fuel injection, and even more after 1996 when the government mandated
that manufacturers start paying attention to converter light-off times.
Electronic fuel injection allowed engineers to run the engine on several
different programs, and change fuel injection timing and the air-fuel ratio for
the engine and operating conditions. This further allowed for the fine-tuning of
start-up programs specifically designed to light the converter off very quickly;
these days, 20 seconds or less isn't uncommon from a dead cold start. Modern
cars also typically use multiviscosity oils that get parts slippery far more
quickly than the old single-weight oils, and those oils tend to do a better job
of sticking to parts after the engine shuts Procedure With any modern car, your
warm-up time at idle should be 30 seconds or less; most cars these days are
designed with minimal warm-up times in mind. So, give your car 30 seconds under
most circumstances, perhaps as much as a minute if you're starting out with 0
degree temperatures, and then slowly set off. Drive easily for the first few
miles to give your transmission, drivetrain and suspension components time to
come up to temperature. It's a myth that idling is the best way to warm a car
anyway. Engines produce more heat under load, so the quickest way to get your
engine up to temperature -- and your heater working, if need be -- is to drive
the car. That goes for cat light-off too; the converter will light off more
quickly while the engine is under load than it will when idling. Try to running
your own test sometimes. Record how long it takes your engine to reach operating
temperature from dead cold after a 30-second warm-up and gentle drive, vs just
leaving it idling in your driveway Autel
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