AUTONET TV

Wasteful Thinking

With the weather getting colder, you might be tempted to start your vehicle up, let it idle for 15 or 20 minutes and then get in the nice, cozy cabin.  Some vehicles offer remote starting that let you do that from the comfort of your home or apartment.  But is letting your vehicle idle like that good for it?

Manufacturers say it doesn't harm the vehicle.  They say it's because modern vehicles are made differently from those in the past.  Just about all newer vehicles employ fuel injection which uses computers to adjust the amount of gasoline that goes into the cylinders.  The engine gets only the fuel it needs, taking conditions into account.

Older vehicles, on the other hand, used to use carburetors.  When you started a cold engine, the carburetor wasn't able to adjust the gasoline amount depending on conditions.  Some of the gasoline would mix with oil and the pistons wouldn't get the same lubrication as they would with undiluted oil.

So yes, you can warm up your newer vehicle for your own personal comfort.  But consider how much fuel you are wasting.  That is not only throwing away money, it's a waste of natural resources.  And it puts more carbon into the atmosphere. 

Automakers have to be mindful of what fuel economy their vehicles can achieve.  So the flip side of the remote starts they offer is a "stop-start" feature.  When you stop your vehicle, even at a stoplight, your vehicle will turn the engine off.  When you take your foot off the brake and step on the accelerator, it starts up right away.  That feature can save as much as 10 percent of the fuel your vehicle uses. 

Your vehicle may not have that start-stop feature, but you can still save fuel by shutting off your engine manually if you are waiting somewhere, like a parking lot or perhaps sitting outside your child's school waiting to pick him or her up.  It saves you money and contributes to a healthier atmosphere for our planet.

Tacky or Techie? The Tachometer.

There's a gauge that many vehicles have that says RPM on it.  And there are a lot of people who either don't pay any attention to it or don't even know what it is. Here's why it's a good gauge to know about.

It's called a tachometer, and that "RPM" label means it is measuring how many revolutions per minute (RPM) the engine is turning.  Automotive experts know that a vehicle's engine can be damaged if it turns too fast (revving too high) or too slowly ("lugging" the engine).

A tachometer (sometimes called a tach) is almost a "must-have" gauge for vehicles with a manual transmission; the driver has to manually change gears; the tach helps the driver know when revolutions are in the optimal range.

Some say you don't need a tachometer if you drive a vehicle with an automatic transmission. It's true that most drivers of automatics don't even look at it.  But there are times when paying attention to the tach can help you prevent an expensive repair.

Here's a good example.  Manufacturers now build many of their automatic transmission vehicles with shift paddles.  They let you shift gears without a clutch. That's manual shifting, and drivers need to know they're not revving the engine too high. That's where the tachometer comes in, since it shows you visually when you are in the red zone (RPM too high).

Here's another way the tach can help you: fuel economy. Generally speaking, the lower the RPM, the better the fuel economy. It's not good to go too low, of course, and the tachometer will help you find that spot of maximum efficiency.

You can also spot problems by paying attention to the tach.  When your vehicle stays in first gear longer than usual (higher reading on the tach), then the RPM dip lower than usual after shifting, it may be that your vehicle's transmission is skipping a gear.  Plus, if your vehicle's RPM go up but your speed doesn't, it could mean your transmission is slipping.  Either situation should be checked by a trained technician.

If your commute takes you down some long grades, you might like to put your vehicle in a lower gear to help slow down the car (and not burn up the brakes). Having a tachometer keeps tabs on when your engine is revving too high.

So, consider the tachometer a "bonus" gauge.  It's one more helpful assistant that can help you spot and prevent problems in your vehicle.