The knocking sound coming from your car’s engine could be a loose accessory belt flapping around. It can also be a detonation problem or worn rod bearings. We are going to talk about the latter two below. J&S Auto Repair can determine why your car, truck, or utility vehicle’s engine has a knocking problem. Once we have figured out the source of the knock, we can fix the issue.
Low-Octane Fuel
If your engine started knocking after you’ve filled the tank, it’s possible that you have the wrong octane in the tank. Standard engines run just fine on fuel that has an 87-octane rating. High-performance engines need higher octane, usually 89 or 91. If the octane in the tank is too low, the fuel will not fire as quickly in the cylinders. Consequently, you will end up with multiple detonations in each cylinder instead of just one detonation. These tiny fireballs are what make the knocking sound.
Bad Engine Timing
Another thing that affects how many times the air and fuel detonate in each cylinder is the spark plugs. If your spark plugs are worn and need to be replaced, you might end up with multiple detonations in each cylinder. It is also possible that your vehicle has a problem with the engine control module, the main computer chip that controls when the spark plugs fire.
Lean Fuel Mixture
A lean fuel mixture also does not fire as quickly as a rich fuel mixture does. Consequently, you will end up with multiple detonations in the cylinders. Things that cause a lean fuel mixture include a clogged fuel filter, clogged fuel lines, or clogged fuel injectors. You may also have a problem with your vehicle’s oxygen sensor or mass airflow sensor. Finally, a faulty fuel pump can also create a problem.
Bad Knock Sensor
Your automobile has a sensor that determines when the engine is knocking. Once it has picked up on the knocking sounds, it will alert the engine control module so it can make adjustments to the air and fuel in the combustion chamber. If the sensor has gone bad, the engine control module will not know that the engine is knocking and fail to make adjustments to correct the problem.
Worn Rod Bearings
Finally, your engine will also knock if the pistons are making contact with the cylinder walls. This happens when the rod bearings wear out and the rods no longer push the pistons up and down evenly.
J&S Auto Repair in Warwick, RI, is here to help, so call us today. We can find out why your engine is knocking and fix the problem.
