Everything You Need to Know About Tachometers

Everything You Need to Know About Tachometers

January 10, 2022

You know that a speedometer measures your engine’s speed, and an odometer tells you how many miles you’ve driven—but there’s another gauge on your dashboard that you might not be as familiar with: the tachometer (or tach).

This post will cover everything you need to know about tachs, including how a mechanical tachometer works and if they’re even needed nowadays.

What is a tachometer used for?

A tachometer measures an engine’s rotational speed and gives us a readout in revolutions per minute (rpm). The higher the meter reads, the faster your engine is rotating. This can be helpful for those driving a manual car, as it can tell them when they need to shift up or down.

How does a mechanical tachometer work?

The answer to “How does a tach work?” is fairly straightforward. In fact, a mechanical tachometer works much in the same way that a mechanical speedometer works. A flexible cable with a rotating shaft is connected to a moving part in the engine. A rotating shaft inside the tachometer controls the position of a needle, indicating the engine’s rotational speed. The faster the engine runs, the higher the reading you’ll get on the tachometer.

How an electrical tachometer works

Electrical tachometers are slightly more advanced. They use a magnetic pickup located near a rotating engine component to produce electrical pulses at a frequency proportional to the engine’s speed. Circuits in the meter convert the pulse frequency to display the rpm on a digital readout on your dashboard.

Are tachometers necessary in today’s vehicles?

You’d be hard-pressed to find a vehicle that doesn’t have a tachometer, but, interestingly enough, these tools aren’t as important as they once were. Although they can give the driver an idea of how the vehicle is running, tachometers are essentially useless due to modern technology.

These days, computers closely monitor your engine’s performance and don’t allow your engine to over-rev. If your engine were to start redlining, the computer would cut off the engine’s fuel supply, effectively slowing the engine down.

What to do if your tachometer is malfunctioning

Even though your tachometer isn’t actually necessary these days, you still don’t want it to give you the wrong readings. A malfunctioning tachometer could be the indication of something seriously wrong under the hood.

If the reading consistently seems to be off or if the tach isn’t giving you a reading at all, you should bring your car to a professional. In addition to fixing the tachometer, your mechanic will perform an inspection and see if something is truly wrong with your vehicle.

Bring your vehicle to Auto Truck Service Inc.

Now that we’ve covered how a tach works, it’s time to learn who to bring your vehicle to for auto repairs. The answer is simple: Come to Auto Truck Service Inc. We have a staff of highly-trained mechanics offering fast repairs at affordable prices. Schedule an appointment today to see what we can do for you. We look forward to assisting you!

Categorised in: