It isn’t that the accessory belt is making the engine knock. Rather, a loose accessory belt will slap around inside the engine and this is the noise that you hear. Urb’s Garage advises, however, that there are things that will make an engine knock. We are going to list the five common causes of engine knock below. Bring your vehicle to our shop as soon as possible if the engine is knocking.
Bad Knock Sensor
Engine knock is a bad thing, and, as such, your vehicle’s engine has a knock sensor to alert the main computer chip when the engine does knock. Many times, the cause of engine knock is an imbalance between the air and fuel in the combustion chamber. When the sensor alerts the computer chip that the engine is knocking, it will adjust the air and fuel to prevent the knock. If the sensor has gone bad, it will not notify the computer chip that the engine is knocking.
Another thing that will make your car, truck, or utility vehicle’s engine knock is the incorrect octane rating of the gasoline you put in the tank. For example, you cannot put lower octane than what is recommended by your vehicle’s manufacturer. If you do, the engine will not because the fuel will fire multiple times in the cylinders rather than just once.
Lean Fuel Mix
Another thing that causes multiple firings in the cylinder is a lean fuel mixture that is heavy in air. There are many things that can cause this type of mixture in the combustion chamber including a clogged fuel filter, clogged fuel injectors, a faulty mass airflow sensor, or a malfunctioning oxygen sensor. You need the right balance of air and fuel to prevent engine knock.
Worn Spark Plugs
As you have figured out, what causes the knocking sound coming from the engine is multiple firings in the cylinders. Worn spark plugs can also cause this problem because they will misfire. You may also have a malfunctioning main computer chip that isn’t firing the spark plugs correctly.
Worn Rod Bearings
Finally, your engine knocking sound may be the pistons knocking against the cylinder walls. This can cause serious engine damage as it can crack the cylinder block. Usually, the thing that causes the contact between the pistons and the cylinders are worn rod bearings.
Urb’s Garage in Erlanger and Burlington, KY, can help, so call us today. We can get to the bottom of your engine knocking sound and repair the problem.