Bad Crankshaft Sensor Symptoms

Bad Crankshaft Sensor: Symptoms, Causes & Fixes

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A crankshaft sensor may appear very insignificant at first sight, but it is a critical tool in the automobile’s combustion plant’s innermost shaft. It asserts and registers the engine’s rotational velocity, and if a crankshaft sensor gets damaged, it cannot convey signals.

This is very important because it is only by the signals transmitted by the sensor signal that the ECU can determine the amount of fuel to take in and control turning on or off the vehicle.

What are the Crankshaft Sensors?

A crankshaft sensor-also known as a crankshaft position sensor-is a piece of electronic equipment located in the internal compartment of petrol and diesel combustion power plants. It helps sends information in the form of signals to the vehicle’s controls and onboard computer. In other words, the crankshaft sensor is built in the car to locate where the camshaft is mounted in the engine, using electric induction.

These signals tell the position of the cranks and how fast the engine is running. There are also different types of crankshaft sensors. These include magnetic, Hall effect, and inductive sensors.

Manually alterable timing marks were installed on gas engines before sensors were invented. Sensors can be installed in different places within the combustion plant. These locations include the crankshaft, crank pulley flywheel, and many more. 

Damage to the sensor can cause the computer to malfunction and not be able to adjust properly, leading to the inefficient and improper functioning of the car’s engine.

How Do They Work?

The crankshaft sensors work by sensing the direction of the magnetic field around the sensor magnet. The voltage from the ECU enters the camshaft sensor, and the output voltage is gotten from the change in MRE resistance. It is the amplified MRE output waveforms that are transmitted to the engine.

Depending on the manufacturers and model of the car, the CKS can be mounted close to the flywheel or crankshaft. It can also be located in the engine block. The mode of operation of the CKS is simple: the speed of the engine causes the spinning crankshaft to produce an electrical pulse pattern. The wavelength of the crankshaft produces onboard computer output circuits, including camshaft, ignition timing adjustments, as well as and fuel injector pulse width. The sensor uses the stator wheel that’s attached to the crankshaft.

Damaged Crankshaft Sensors Symptoms

What if the crankshaft sensor fails or gets bad? There are signs a car owner or driver should be looking for. They include intermittent stalling, random engine misfire, and no start.

  • Combustion Plant Fails When Hot

The combustion plant refuses to come on when hot but easily comes on when cooled, or the engine may not start at all because the crankshaft sensor plays a vital role in starting up the engine. All these are malfunctions resulting from a faulty sensor.

  • Fuel Inefficiency

The amount of fuel consumed by the vehicle’s combustion engine would be unusually high, and this is because the sensor that ought to regulate fuel ingestion has stopped performing its duties. Although other problems could increase gas consumption, a faulty sensor is very prominent amongst the others.

  • Clicking Sound

A clinking sound is heard repeatedly, and this occurs because the crankshaft has fallen and leans toward the engine’s belt. Over time this makes the metal plate around the sensor hit the sensor as the belt revolves, producing a clink repeatedly.

  • Engine Light On

The automobile’s check engine light would also come on, which is very much an indication of a faulty sensor.

  • Engine Vibrates

The engine vibrates when you attempt to turn it on, which is explained by the fact that the sensor detects the piston’s location, and with this information, proper optimization could occur. But if the sensor is faulty, there would be no way for the power plant to identify the piston’s position causing the vibration observed.

  • Intermittent Stalling

The vehicle would move at speed and then slow down irregularly, alerting you of the lack of accurate information due to the damaged sensor.

Causes of Bad Crankshaft Sensors

Apart from corrosion of the sensors harness pins, there are other reasons your car’s crankshaft sensor can get bad. Here are the top causes of a faulty crankshaft sensor:

  • Intense Heat: Excessive heat occurs because the engine is not well lubricated with transmission fluid or enough air is not getting to it due to a faulty radiator. Whichever it is, though, this excess heat build-up would cause the sensor’s encasement to melt. When this happens, the sensor will not transmit signals, and eventually, the car would not start.
  • Problems From the Circuiting Wires: Excessive vibration could disconnect the wire, wear and tear, too high or too low voltage, oil, and dirt, loose wires, reflected current, and so on could interrupt voltage flow, and the vehicle would crank but refuse to be powered up.
  • A Tear of the Timing Belt: If the timing belt comes off unexpectedly, it could damage the crankshaft sensor or even the wire harnessing. If you observe a damaged timing belt within your vehicle, it would be wise to check the sensor for clues of damages.

How to Fix Bad Crankshaft Sensor & Cost?

The first thing to do whenever you suspect that your car’s crankshaft position sensor is failing or bad is to carry out a diagnosis. if there is any sensor-related trouble code displayed, you should carry out a test. 

To do this, try to visually inspect the sensor if there are any cracks. Also check for any rusted, missing, corroded, or lose connector pins. You should also check if the gap between the reluctor and edge of the sensor has been clogged. 

Once you discovered none of these happened, you can refer to the owner’s manual to check the proper testing procedure. If the problem is with the pick-up-type sensor, you should inspect the resistance: if resistance is high or lower than normal, you should replace it.

However, a hall-type coil sensor, check the ground signal and +5V voltage. You can carry out this test with the use of an oscilloscope.

Depending on your vehicle type and model, you would spend anything between 30-300USD to purchase a suitable sensor. After that, you could pay the automobile engineer as much as 500USD to install the sensor. This fee depends on how much damage the engineer has to repair.

Final Thoughts

Crankshaft sensors are very important in the engine’s normal functions; therefore, anything that would compromise their ‘well-being’ should be avoided or corrected on time. make sure your crankshaft sensor is always in a good condition. Its failure can be telling on the overall performance of your vehicle. 

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