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Can you please say something about fuel injection and the...

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Dear Tom and Ray:



Can you please say something about fuel injection and the need for being careful
NOT to step on the gas before starting up the car? Why don't dealers impress this
upon customers who buy fuel injected cars these days? -- Dorothy

TOM: Mostly because it doesn't matter, Dorothy. In the old days, when my brother
had hair and Dodge Darts roamed the earth, you HAD TO step on the gas before
starting a cold car to set the choke. But since cars don't have chokes anymore,
that's no longer necessary.

RAY: Cars are now fuel injected and controlled by computerized engine-management
systems, which read the engine temperature, and in some cases the ambient air
temperature, and then determine how much fuel and air to send into the cylinder
when you turn the ignition key.

TOM: And these computers couldn't care less if you step on the gas pedal before
you start up. As long as your foot is not on the pedal while you're turning the
key, any such "pre-stomping" will have no effect whatsoever.

RAY: But you do have a point when it comes to stepping on the gas pedal WHILE
you're starting the car. While stepping partway down on the gas doesn't do any
damage to the car, it does make some cars start more slowly. That's because you
may be opening the throttle slightly when the computer wants it closed. Again, no
damage is done, but it's completely unnecessary and may make starting the car
harder.

TOM: Another reason to get out of the habit of stepping on the gas WHILE you
start the car is that as soon as the car starts, it's going to rev up. And we
know that revving up a stone-cold engine as soon as you start it is one of the
worst things you can do.

RAY: The other thing you should be careful not to do is related to what's called
a "W-O-T mode."

TOM: Oh, my Dodge Dart was in W-O-T mode last year. With-Out Transmission!

RAY: No. W-O-T stands for "wide-open throttle." In the old days, when my brother
had brain cells and the Earth's
crust was still warm, carbureted cars had a mode for starting the car when the
engine was flooded. You held the pedal all the way to the floor while you turned
the key. That opened the throttle all the way and let in the maximum amount of
air to counteract the excess gasoline.

TOM: And most car's computers are designed to "mimic" that W-O-T mode. So if you
hold the gas pedal to the floor while turning the key, the computer assumes the
engine is flooded and cuts the supply of gasoline in half. So that's something
you want to be careful not to do by accident.

RAY: But stepping on the pedal BEFORE you start the car really doesn't matter,
Dorothy. Stomp on it, pump it to the beat of "Stayin' Alive" or just leave it
alone; as long as your foot is off the pedal by the time you turn the key, a
fuel-injected car couldn't care less.
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