If you are Audi or other European automobile’s engine knocks all the time, RB Auto Service advises that you likely have a problem with the engine’s detonation. Detonation happens when the spark plugs ignite the air and fuel in each cylinder. There should only be one detonation in each cylinder, but extenuating circumstances can cause multiple detonations in the cylinders. When this happens, the engine makes a knocking sound. Let’s discuss the four causes of detonation knock below along with a bonus cause.
Bad Knock Sensor
To prevent detonation knock, your engine has a sensor that alerts the engine control unit if the engine starts to knock. This allows the unit to assess the amount of air and fuel in the combustion chamber and make adjustments to smooth out the detonation. If the knock sensor has gone bad, the engine control unit will not be notified of engine knock. Consequently, your engine will continue to knock until the sensor is replaced.
Lean Fuel Mixture
One thing that can cause multiple detonations in the cylinders is a lean fuel mixture. What this means is that there is excess air in the mixture and not enough fuel. This mixture does not fire as fast as a normal or rich fuel mixture. Consequently, the slow detonation will result in multiple detonations in the cylinders. This is the engine knocking that you hear.
Low-Octane Fuel
Low-octane fuel also fires slower than high-octane fuel. A standard engine runs just fine on low-octane fuel because the detonation in the cylinders is slower. If you drive a high-performance automobile, however, you need to use high-octane fuel in the engine to prevent engine knock. Check your owner’s manual to see the recommended octane rating of the fuel you should put in the engine.
Misfiring Engine
A misfiring engine makes knocking noises. This is because the engine timing is off. In other words, the spark plugs are not firing in the correct order. If your engine control unit is going bad, it might be firing the spark plugs out of order. Another thing that will cause a misfiring engine is worn spark plugs.
Worn Rod Bearings
Finally, we mentioned a bonus cause of engine knock and this is worn rod bearings. These bearings ensure that the rods move the pistons up and down in the cylinders without making any contact with the cylinder walls. If the bearings are worn, the pistons will crash against the cylinder walls. This is the knocking sound you hear.
Call RB Auto Service in Pinellas Park, FL, if your European automobile’s engine knocks all the time. We will determine the cause of the knock and repair it.