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We rarely think about our car’s speedometer. But what happens when we see the speedometer reading faster than the actual speed?
It may prevent us from traveling at an appropriate speed and can turn into a cause of concern.
Most car owners know how to fine-tune their cars. But when it comes to our speedometers, we can get a bit lost.
For this reason, we will tell you what to do when the speedometer is reading faster than the actual speed.
In addition, we will also let you know all the possible causes that may lead to such a situation.
Reasons Why Your Speedometer Is Reading Faster Than Actual Speed
Many things can cause your car’s speedometer to read faster than actual speed.
A blown fuse or damaged wiring in a speedometer can be the reason for its malfunctioning.
Similarly, a poor sensor and engine control unit can report an erroneous speed on your speedometer.
A change in the tire size or wheel can even contribute to a misaligned sensor.
Another problem with speedometers is that they tend to give inaccurate speed when the speed sensors malfunction.
If you see that the light of your engine is ‘on,’ it may be a sign that there is something wrong with your speedometer.
Hence, it is essential to take immediate action when you see this.
Tires And Speedometers
If the diameter of tires changes, you may have a speedometer reading faster than the actual speed. It will give you an inaccurate calculation and estimation.
For instance, if you get new tires for your car, the diameter will increase or raise the tire’s pressure.
It will mean that you will have a higher speed for each tire rotation the further your car travels.
On the other hand, there may be a decrease in the diameter. It is due to changes in the tire brand in terms of dimension and design.
It can result in low air pressure, making the car travel shorter distances for each wheel revolution, and your car will move slower.
Manufacturer Design
Another reason for the higher readings is manufacturer design.
In most vehicles, the speedometer is calibrated to read above or at the exact speed limit by at least 10%.
They do this as a precautionary measure. Sometimes, the car may be going faster than the speedometer reading.
This slight configuration change done by manufacturers takes care of this difference caused in the reading and keeps drivers from over-exceeding their limits.
Condition Of The Roads
Are you driving over a rocky or uneven patch? A lesser-known reason for the speedometer’s botched-up readings is the road conditions.
We can measure a car’s speed by the number of rotations its wheels make. Driving on bad roads can cause a miscalculation.
It can result in the speedometer reflecting higher readings than expected. It is temporary and gets fixed while you move on to normal roads.
If it still isn’t fixed, you may have to visit the mechanic.
How Can You Fix A Speedometer Reading Faster Than Actual Speed? Solutions
When the speedometer is reading faster than the actual speed, you need to fix it with the following solutions.
Change Your Speedometer Cables
If you see your speedometer reading faster than actual speed, remove the engine’s cover and look at the entry point of the cables.
You will find a thick black wire leading to the instrument cluster, the speedometer cable.
Take the bolt out from underneath the dashboard so that you can access the old cable easily.
You can then remove its nut on the transmission and pull your cable out through its passage.
Removing the clamps on the engine compartment and transmission that hold the cable will help you fix your speedometer reading faster than the actual speed.
You can further replace the old cables and put a new one in its place.
In your car’s adapter, you can fix the square of the new cable and tighten the nut on a rotating shaft.
You will have to pass your new cable through a passage and tighten the bolt at the rear end in the final step.
Check The Speed Sensors
Another way you can fix your speedometer reading faster than actual speed is to find the speed sensor behind your engine above the trans-axle.
You can remove your electrical connector, air cleaner, connecting hose above your sensor.
With a 10 mm socket, remove the bolts while keeping the sensors in their place and twist the sensor to remove it.
Attach one O-ring to your speed sensor and clean the exterior sensor housing and the sensor flange before reinstalling it.
Then keep the new sensor in its place and tighten the surrounding bolts. Reattach your electrical connector, air cleaner, and hose to your sensor at the end.
You will get your speed sensor on the driver’s side behind your car’s transmission. Once you find it, raise your vehicle from that side with the help of a car jack.
Then, you will have to remove your wheel.
Finally, disconnect your electrical connectors on the sensor and remove the bolts while keeping the sensors in place with the socket.
Replace the O ring and attach and tighten the electrical connector.
How Can You Calculate The Speed When The Speedometer Is Reading Faster Than The Actual Speed?
When there is a problem, you will see your car’s speedometer reading faster than the actual speed.
In this case, you will have to find out the actual speed to compare the speed with what your speedometer shows.
You can find highways that have mile markers as per which you can drive at a certain speed consistently for a specific time.
Bringing a stopwatch will help you measure how much time it takes to travel and cover a certain amount of distance.
You can jot down the speed when your speedometer reads faster than the actual speed.
Then divide sixty by the time of travel in minutes, take seconds in the form of fractions, and multiply it by the number of miles you traveled.
It will help you get your actual speed.
What Is The Function Of A Speedometer?
We all know that speed refers to the measurement of distance over time. But the car’s speedometer does not measure the speed of your travel.
It measures the rotation of the car’s wheel, driveshaft, or axle. So, by estimating the rotations, the speedometer determines how fast you are traveling.
Conclusion
A speedometer is reading faster than the actual speed can be a genuine problem. In such cases, it is essential to determine and discern the leading cause of the problem.
It is because a speedometer can malfunction due to several reasons.
Some of them include damaged wiring, blown-fuse, poor engine control unit, or a malfunctioning sensor.
At times, it can also be due to a change in the wheel or the size of the tire. However, there are different ways by which you can fix your speedometer.
For instance, you can remove the speedometer cables or replace the sensors.
James has been a car enthusiast since his childhood when he learned the differences between a ford and a chevy from his father. He loves to drive and restore old cars with a special drive for Italian marvels. Currently, he has a 1968 Alfa Romeo. He has studied aeronautics and civil aviation in his college and still gets smitten by Galant SS and Lancer GSR.
He is a New York-based product training director working with a giant automotive retailer. He loves to review and uncover the vehicles and their fascinating stories. He believes in keeping it legitimate with a keen passion for research on the latest technological upgrades in cars. While reading his articles or blogs, you can sense the extensive research and dedication backing the piece of text. He loves fried chicken, music, and spending quality time with his pet dog.
