Noise when accelerating from stop is a sign that your engine has become faulty. These signs are common problems that could be coming from the brakes, transmission or engine. Fortunately, fixing them isn’t as difficult as you might expect, but you need to act quickly to avoid compounding the problem.
In this blog post, we’ll discuss the various sources of the noise and suggest ways you can fix them.
JUMP TO TOPIC
- 1 What Causes Noise When Accelerating From Stop?
- 2 How To Fix the Noise When Accelerating From Stop
- 3 Conclusion
What Causes Noise When Accelerating From Stop?
The causes of noise when accelerating from stop are faulty spark plugs, damaged exhaust system or bad fuel injectors. Other sources of the unsettling sounds in the vehicle include a loose engine belt, lower-grade fuel, inferior engine oil, or a bad clutch.
Faulty Spark Plugs Causing Engine Misfires
Spark plugs ignite the air/fuel mixture in the combustion chamber to produce enough power to move the vehicle. They do this as soon as the air mixes with the fuel and missing their timing results in engine misfires. Thus, when a spark plug is faulty, it is unable to light up the air-fuel mixture at the right time, and this causes engine misfires which result in frustrating noises from the engine.
Also, faulty spark plugs prevent the air/fuel mixture from burning completely and rob the engine of the necessary power to operate at full capacity. When the engine loses power, it struggles to speed up the car regardless of the amount of pressure you place on the accelerator. Sometimes, faulty spark plugs cause the engine to vibrate when idling and can make the vehicle jerk when driving at lower speeds.
They also cause a decrease in fuel economy, making your vehicle expend more gas than necessary to function. The main causes of faulty spark plugs are age or leaking engine oil, and must be replaced to ensure the engine operates efficiently. It costs between $450 and $300 to replace the plugs, but you can cut down the cost drastically by doing it yourself, which we’ll discuss soon.
A Damaged Exhaust System Making Unsettling Sounds
Another cause of rattling noises is a damaged exhaust system due to a loose component or a broken pipe gasket. The exhaust system consists of a tailpipe, a catalytic converter, a muffler, an oxygen sensor, an expansion chamber, etc, and damage to any of these can cause noises.
During combustion, harmful gasses are eliminated from the vehicle through the exhaust system. The gasses pass through all the components mentioned above and out of the vehicle; thus, any leak in any of them might generate noises when accelerating from stop.
For example, one part of the system that commonly suffers leaks is the exhaust manifold. Exhaust manifolds are metallic components that collect exhaust gasses and direct them to the cat converter. The converter then turns these dangerous gasses into less harmful ones to be reused by the car or released into the environment.
However, when there’s a leak in the exhaust manifold, the exhaust gasses will seep through the cracks and cause a loud noise. This is also true of the muffler, a component that dampens the noise from the engine. If the muffler develops cracks, the gasses can escape through the spaces and cause a bang when you accelerate from rest. If left unattended, you’ll hear a muffler noise when accelerating.
Faulty Fuel Injectors Causing Misfires
A Faulty fuel injector can also cause misfires leading to noises when it supplies too little or excess fuel to the engine for combustion. Fuel injectors spray gas into the combustion chamber, where it mixes up with the air and is ignited by the spark plugs to produce power.
These fuel injectors are controlled by the electronic control unit (ECU), which tells the injector the quantity of fuel and timing. However, fouled fuel injectors might not properly interpret the signals from the ECU and spray excess or insufficient fuel.
Spraying excess fuel leads to rich combustion, which causes a sudden surge in acceleration. However, when the amount of fuel is too little, it leads to lean combustion, meaning the engine won’t get enough power to support its work. Both cases can cause misfires which would lead to noises when accelerating from stop.
Noise Caused By Engine Belt and Loose Brake Pads
Loose engine belt and brake pads can generate noise when you accelerate from stop. However, it can be difficult to tell the source of the noise. If the squeaking noise is coming from the engine, then it could be the engine belt. But if the noise coming from under the car, then you should suspect the brakes.
The engine belt produces power and distributes it to the engine accessories to get them going. However, some components that hold the belt in place can become loose and create noise when the engine is running.
Loose brake pads can generate squealing noises when you drive at slow speeds. For example, the pads can rub against a few components of the brake system, which can generate unsettling noises. Also, the loose brakes may start to resonate within the caliper bracket and generate noises. The sounds can only be noticed at low speeds, especially when there’s less noise from the engine or surroundings.
Lower-grade Fuel Detonating Inside Engine
Putting lower-grade fuel in your car can cause a rattling sound when accelerating at low speeds. The noise is the result of detonation in the combustion chamber. Detonation occurs when the air/fuel mixture detonates instead of burning evenly and consistently. If you use the right fuel grade for your vehicle, the spark plugs will burn it and produce enough energy to power your vehicle.
However, the energy produced won’t be enough to power the car. This leads to delayed acceleration and poor engine performance. Knowing the fuel type and the fuel grade your vehicle uses will save you money in the long run.
Using Inferior Engine Oil for Your Engine
The motor oil’s duty is to lubricate the metallic moving parts of the engine so they don’t rub against each other. Thus, the oils must contain certain chemicals and characteristics, such as perfect density and viscosity, to perform their jobs efficiently. That is the reason why many car companies also produce specific oils designed to suit their engines.
Inferior engine oils are usually less dense and thus can’t properly lubricate the moving parts of the engine. Thus, the moving parts grind against each other, and this grinding action is the reason the car makes humming noise when accelerating. The same thing may happen if you don’t use the specified motor oil for a particular vehicle brand.
How To Fix the Noise When Accelerating From Stop
To fix the noise when accelerating from stop, you must first find out the source of the noise. After determining the source, you take the appropriate steps to rectify that particular situation. For example, if the source is a leak from the exhaust system, find it and seal it.
If it is putting the wrong fuel or low-octane fuel in the gas tank, drain it and fill it with the right fuel. However, faulty plugs, engine belt and fuel injectors will require replacement.
Fixing Leaks in the Exhaust System
Repairing the leaks in the exhaust system involves using sealants or welding, depending on where you have the leaks. If it is from the manifold or any of the joints in the exhaust system, you can just replace the old gasket there. This is because the manifold and joints in the system have gaskets that are replaceable, but you’ll have a little bit of difficulty when removing the bolts due to rust. Once the bolts are out of the way, slide the new gasket in and screw the new bolts into place.
However, if the leak is coming from a crack or hole, widen the leak to ⅛ inches with a slender drill bit, making sure it’s the same width from end to end. Remove the debris around the area with low-grade sandpaper and clean the area with a foaming engine cleaner. Next, rinse the area twice with water and detergent solution and seal the crack with a metal repair paste. You can now allow the paste to sit for about 24 hours before turning on the engine.
Next, sand the metal repair paste to get rid of lumps and give it a smooth finish. Ensure you replace any other parts you may have removed before getting to the leak. However, if you run into a fix, don’t hesitate to send the vehicle to a mechanic for help.
How To Clean Faulty Fuel Injectors and Replace Spark Plugs
To clean the injectors, you’ll need canned air, a funnel and an injector cleaner. The first thing to do is to remove the old fuel injectors and clean them with canned air. Next, pour a handful of injector cleaner into the funnel and then onto each injector’s opening, according to the directions on the label. Allow the injectors to dry in a dust-free environment and then fix them into the engine.
When it comes to replacing the spark plugs, you’ll need a ratchet, an extension, a spark plug socket and new spark plugs. Remove the old spark plugs with the spark plug socket and disconnect the wires. Ensure you label all the wires appropriately so you’ll know where each one goes after changing the spark plugs. Now, install the new spark plugs and tighten them with the ratchet.
This article has explained why you hear clicking noises when accelerating at low speed from the start and suggested ways to combat the problem.
Here’s a recap of the main points:
- A loud rumbling noise when accelerating could be the result of bad spark plugs, faulty fuel injectors, a damaged exhaust system, and the wrong fuel type.
- A loose engine belt and pouring an inferior motor oil can cause clicking sounds from the engine.
- Inferior engine oil may cause the moving parts of the engine to grind against each other, producing a knocking sound when accelerating at low speed.
- You can replace the bad spark plugs and clean the faulty fuel injectors to get them functioning properly.
- The inferior engine oil and low-grade fuel can be changed and replaced with products that are fit for purpose.
Look for leaks in the exhaust system, and when you find one, use the appropriate measures to fix it. If you face difficulties, contact a mechanic to help you resolve the issues.
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