What would happen to a car if the crankshaft sensor were faulty?

Can A Bad Crank Sensor Cause A Car Not To Start?

When a crankshaft position sensor fails, it is most common for the vehicle to start slowly. It is possible that the crankshaft position sensor is malfunctioning, causing intermittent problems with the vehicle starting.

5. Engine Misfires or Vibrates

Should you feel or hear a brief stutter in the engine, it may be a sign of misfiring cylinders from a bad crankshaft position sensor. A failing crankshaft position sensor cannot provide the right information about piston positioning in the engine, causing a cylinder to misfire. This could also occur from faulty spark plug timing, but if the spark plug checks out, then the crankshaft sensor is likely the source.


What causes the crankshaft sensor to go bad?

As well as knowing the symptoms of a faulty crankshaft position sensor, knowing what can cause these faults can also help you avoid costly car problems.

Overheating engine

An overheating engine can cause many problems. One of these is the crankshaft sensor’s plastic covering being melted or damaged.

Circuitry issues

Damaged or loose wiring and faulty voltage can cause problems with the signals sent to the engine control unit by the crankshaft position sensor.


How long does a crankshaft sensor last?

Some crankshaft position sensors might last for the entire lifetime of your car, and there is no set time for you to replace them. The likelihood of crankshaft position sensors failing will increase after 100,000 miles.

Looking out for the symptoms described in this article, especially in older cars, will give you the best opportunity of getting the issue resolved before it causes further damage to the engine.

Can a bad crankshaft sensor cause no start?

The crankshaft sensor measures the engine RPM and traces the position of the crankshaft. If the crank sensor fails or its wiring is damaged, this can cause many engine issues, including stalling and the inability to start the car.

The sensor will send a signal to the ignition coil that is managed by the control unit. If the engine control unit is receiving incorrect information or no information from a bad crankshaft position sensor, the coil will not be able to be turned on or off.

How long does it take to replace a crankshaft sensor?

The length of time it takes to replace a bad crankshaft position sensor will differ depending on the make and model of the vehicle. On average, it should take an experienced mechanic around one or two hours to carry out the replacement.

Can you drive with a bad crankshaft sensor?

Driving with a bad crank sensor is possible, but it is definitely not advisable. If you have noticed any of the symptoms mentioned above or you have an illuminated check engine light, getting it checked over by a qualified mechanic as soon as possible could save you a lot of money.

The most important reason that you shouldn’t drive with a bad crank sensor is that it is not safe. If the sensor is unable to provide the ECU with the correct information, it will not know when to fire the fuel injection system and ignition spark plugs. This can cause the car to stall no matter what speed you are traveling at.

Running a vehicle with a bad crank sensor can also cause damage to the engine, meaning it is not only dangerous to drive, but it can lead to severe damage that will be very expensive to repair.

Can You Drive With A Bad Crankshaft Position Sensor

It is never advisable to drive a car with a bad crankshaft position sensor. An improper ignition timing is bound to have serious damaging effects on the engine and much more importantly can put your life at risk. It’s best to get it replaced as quickly as possible.

In some cars, to avoid extremely poor functionality, the engine computer may try to substitute the bad crankshaft sensor with the camshaft position sensor though with tripping a code alongside. And usually, a car cannot compensate for such issues for long. So, If you suspect a bad crankshaft position sensor though do not experience the symptoms quite as much severely, you must still have the device checked for wiring and fuse issues before driving any further as the symptoms can exacerbate rapidly if not paid heed to.

2. Intermittent Stalling

Another symptom commonly associated with a problematic crankshaft position sensor is intermittent stalling. If the crankshaft position sensor or its wiring have any issues, it can cause the crankshaft signal to be cut off while the engine is running, which can cause the engine to stall. This is usually a sign of a wiring problem. However, a bad crankshaft position sensor can also produce this symptom.

What Happens When A Crankshaft Sensor Goes Bad?

There are many times when crankshaft sensors fail, causing engine misfires, stalling, and stalling while driving. When the engine is idling, one of these sensors is most likely to fail. The sensor will start working again once the engine cools down.

Is It Hard To Replace A Crankshaft Sensor?

A mechanic who has to perform a crankshaft sensor repair will spend a considerable amount of time removing the crank sensor, so as not to damage anything else. They can be a bit difficult to take off, due to sensor’s ability to get stuck in the block. The sensors also have a long stem, making removal difficult.  After the sensor has been taken loose, the mechanic will grasp it and begin the work of the repair. 

Tachometer Doesn’t Work When Cranking

Since the tachometer essentially gets the RPM readings from the crankshaft position sensor, it can be a pretty clear sign if the gauge starts to malfunction. Generally, the RPM gauge does not give up altogether but it can be rather hard to judge if the readings are actually inaccurate when the vehicle is in motion. One way you could look to see a problem with the RPM gauge is when you crank the engine. 

The tachometer is not where most people would turn their eye when cranking the engine though it can be one thing to see when you have a prolonged crank. One of the purposes of the crankshaft position sensor is to measure crankshaft RPMs. So if the crankshaft position sensor is not working properly, it could cause your RMP gauge to not work.

Rough Idling

You might feel that the engine runs rough or vibrates at idle, say, when you’re sitting at a red light. This is similar to the above in that it stems from poor spark timing.

Reduced Gas Mileage

Without accurate timing information, fuel injection won’t occur as efficiently as it should. That means the engine will need to use more gas and your morning commute will use up more fuel than usual.

Most Common Signs of a Failing Crankshaft Position Sensor

When a crankshaft position sensor is bad or failin

When a crankshaft position sensor is bad or failing, it will give a series of signs that you can identify and diagnose your vehicle. To be absolutely sure about your diagnostics, you will need a scanning tool. (check prices on amazon.com). Here are the 5 most common signs of a failing crankshaft position sensor:

1. Vehicle cannot start

The crankshaft position sensor is part of the timing system. It monitors the speed of the crankshaft and its position. When the piston reaches to top dead center, the crankshaft position sensor sends information to the ECU, and the ECU coordinates with the ignition and fuel injection system.

When the crankshaft position sensor fails, simply due to normal wear and tear, obstructions, or interference it cannot perform its duties. Meaning, a faulty crankshaft position sensor can no longer send accurate information about the position of the piston and the computer will not spray fuel into the engine.

2. Vehicle stalls while driving

When the crankshaft position sensor is failing, it can cause intermittent stalling. The vehicle may stall at all speeds. The ECU will not receive any reliable signal from the crankshaft position sensor, therefore, interfering with the timing system. At this point, the engine may shut off at any time due to lost timing signal. Simply, the ECU will no longer spray fuel into the engine and your engine will shut off.

3. No fuel injection pulse

No fuel injection pulse is a sign of a failed crankshaft signal. The crankshaft sensor sends a signal to the ECU and the ECU determines when the fuel injector should spray fuel into the engine and how much.

It’s best if you use a scanning tool and run diagnostics on your vehicle. The scan tool will tell you exactly what is wrong with your vehicle.

4. No RPM movement while cranking

If the RPM needle on your dashboard is not moving while you are cranking your vehicle, this means there is no crankshaft signal. This symptom will not apply to all vehicles, but you can combine it with some of the previous symptoms and determine if your crankshaft position sensor is faulty.

5. Interference from

A broken timing chain, broken timing belt, broken harmonic balancer, and open wires can cause premature wear and failure to the crankshaft position sensor. A broken timing belt will damage the crankshaft position sensor and the interference engine.

Make sure the crankshaft position sensor is not wet from engine oil that could be leaking from the front seal or crankshaft seal. Also, check for coolant leaks from the water pump.

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