The crankshaft is one of the most important parts of a modern vehicle as the speed and position of the crankshaft deal with engine management. The calculations and the information the engine control unit uses to make adjustments controls everything from how a car runs to whether it will start. Where does a sensor come into this?
Well, the sensor is just as essential since most engines won’t even start if they are not in the right position. Therefore, if you aren’t aware of the signs, you could be a piece of bad luck away from a breakdown. However, it is possible to rectify the situation by watching out for the warning signs.
#1: It Won’t Start
Not starting, or starting irregularly, are symptoms of a faulty crankshaft sensor because it means the sensor isn’t providing the signal to the ECM correctly to monitor the position and speed of the crankshaft. As a result, the engine can’t start because it needs the data from the crankshaft to start. If it happens once or twice, it could be down to a minor issue... but if the problem continues, you should speak to a mechanic about looking under the hood.
#2: The Engine Keeps Stalling
Even if the engine starts, that doesn’t mean you’re out of the woods. This is because the engine will stall if the signal from the crankshaft is cut off at any point. Sometimes, faulty wiring is the reason; however, you can’t rule out a bad crankshaft position sensor either, as it can also lead to the issue. Of course, anyone can stall a car or other vehicle since it doesn’t take much to get the bite of clutch wrong. Still, randomly cutting out in the middle of a journey isn’t a driver error, so it’s an obvious sign if it does it of its own accord.
#3: Low Fuel-Economy
When the crankshaft sensor isn’t working properly, it won’t relay information to fuel injectors correctly. Two things can then happen, with one of them being uneven acceleration. If you can’t speed up when you press the gas or struggle to maintain a constant speed, the crankshaft sensor could be the problem. More common it can lower fuel-efficiency. Without knowing how much gas to pump into the engine, the injectors will guestimate. The result is often too much fuel, which causes you to use more than you require. A smart tip is to watch the gauge on short journeys as you can see the effects of reduced mileage when you don’t travel long distances.
#4: Engine Light
It’s worth noting that a check engine light can relate to a range of issues, many of which might have nothing to do with a crankshaft sensor. Still, a fault in the system will be picked up by a modern vehicle’s computer. The computer will make a signal on the dash, and you’ll have to figure out what it means (if it doesn’t tell you outright). In this case, a good option is to check for any other signs that could lead you to the root cause. For instance, if an engine light appears after the car won’t start or stalls randomly, you can deduce that the crankshaft may be to blame. If you have access to an OBD2 scan tool, you can check to see what code is being thrown. If you do not have access to a scan tool, you’ll need to take it to a mechanic to have them check for the codes. The codes should tell you what part/sensor is at fault.
Hopefully, these pointers will help you to tell when you have an issue with the crankshaft sensor.