Why Is My Engine Knocking All the Time?

You do not want your automobile’s engine to tell you knock-knock jokes. If your engine is knocking all the time, there could be something seriously wrong underneath the hood. George Automotive Services warns that the knocking has the potential to damage the cylinder block or other crucial engine parts. Let’s talk about the causes of engine knocks below.

Bad Knock Sensor

It is so important that your engine doesn’t knock that it has a knock sensor. If the sensor detects an engine knock, it will alert the engine control module. Also called the ECM, the engine control module will make adjustments in the engine to prevent it from knocking. If the knock sensor goes bad, it won’t be able to alert the ECM that the engine is knocking.

Bad Timing

Misfiring can also make it sound as if your engine is knocking. This is called a detonation knock. The reason it is called this is that there are multiple firings of air and fuel in each cylinder because the spark plugs are firing incorrectly. These additional detonations make knocking sounds in the cylinders. The spark plugs could be misfiring because they are old and worn or because the ECM is malfunctioning and firing them out of sequence.

Lean Fuel Mix

Another thing that causes detonation knock is a lean fuel mixture. Lean means that the fuel mixture is heavy in air and light in gas or diesel fuel. This also causes multiple detonations in the cylinders and, as such, that annoying engine knock you hear while you are driving your automobile. A malfunctioning MAF or O2 sensor can cause a lean fuel mixture, as can a clogged fuel filter.

Low Octane

If you put the wrong gas in your automobile, it will knock. For example, if you drive a high-performance automobile that requires 91 octane and you put 89 or 87 octane in the tank, your engine is going to knock because, again, you’ve got multiple detonations going on inside the cylinders.

Worn Rod Bearings

Finally, as we mentioned in our intro, engine knock can be a sign of a serious problem in the cylinder block. If the rod bearings have worn out, the pistons are no longer able to move up and down inside the cylinders smoothly. Rather, they bang against the cylinder walls. This can cause serious engine damage.

A loose accessory belt may also be slapping around inside your engine and this may sound as if the engine is knocking. Call George Automotive Services in Danville, PA. We will get to the bottom of the strange knocking sounds coming from your vehicle’s engine.