RPM refers to the rotation speed of the vehicle’s engine. But you might have faced the “car won’t accelerate but RPMs go up” problem at some point or another.
Because often, when the car is old or due to any other reason, due to the failure of many parts related to the engine, the car won’t accelerate but RPMs go up. It can actually be a sign of a mechanical problem.
However, the “car won’t accelerate but RPMs go up” problem can also have many more serious causes related to the engine and transmission, and repairing or replacing other parts related to these causes can also be a high-cost task.
In this article, we will learn about the main reasons why the car won’t accelerate but RPMs go up, as well as how to diagnose and troubleshoot the problem.
What is Engine RPM?
RPM measures the rotational speed of the crank shaft of any engine. The full form of RPM is “Round Per Minute”. RPM measures how many times the engine’s crank shaft rotates in one minute. RPM measures the speed of the engine’s crankshaft.
To display the RPM of the engine in vehicles, the cluster meter on the dashboard has an RPM gauge, and according to the speed of the engine, the engine RPM shows in the RPM gauge.
Some vehicles have an RPM gauge with a needle; in the RPM gauge, this needle moves up or down according to the engine speed, and some modern vehicles have a digital RPM gauge. The digital rpm gauge displays the number of the engine’s rpm. RPM plays a vital role in the efficient operation of the engine and transmission. Many functions of the vehicle depend on the RPM of the engine.
Why Does Your Car Won’t Accelerate But RPMs Go Up?
The most common cause of car won’t accelerating but RPMs go up is a worn clutch or a faulty torque converter. Additionally, causes may include low or contaminated transmission fluid, improper lubrication, transmission slipping, transmission solenoid or sensor malfunction, and a clogged catalytic converter.
Let us go through these possible reasons in detail one by one.
1. Worn Clutch Plate
Often, in a manual transmission car, a worn clutch can also cause Car Won’t Accelerate But RPMs Go Up, as a worn clutch plate keeps slipping along the engine’s flywheel during acceleration, causing the engine to lose power over time.
Power is not getting to the wheels, which can cause the RPM to go up during acceleration, but the car will not accelerate. This problem also increases fuel consumption.
2. Failing Torque Converter
The torque converter is an important part of an automatic transmission. In automatic transmission vehicles, the torque converter is the only one that transmits engine power to the vehicle’s wheels without the need for a clutch.
But in an automatic transmission car, torque converter failure can also cause Car Won’t Accelerate But RPMs Go Up, causing symptoms similar to a slipping clutch in a manual car. A failed torque converter may also cause the vehicle not to accelerate, but the rpms may go up.
3. Transmission Low Fluid Issue
In automatic transmission vehicles, the torque converter works with transmission fluid. But a low automatic transmission fluid level can also cause the Car Won’t Accelerate But RPMs Go Up problem, as low transmission fluid affects the operation of the impeller and turbine in the torque converter. Therefore, even low transmission fluid may not accelerate the vehicle properly.
4. Faulty Fuel Filter
In many cases, a faulty fuel filter also hinders the vehicle’s acceleration. Because the engine needs more fuel during acceleration. But the clogged fuel filter is not able to supply the required amount of fuel to the engine during acceleration.
5. Faulty Oxygen Sensor
The oxygen sensor in the vehicle’s exhaust system measures the amount of oxygen in the exhaust and transmits it to the vehicle’s ECM. Based on this signal, the vehicle’s ECM sends fuel mixture to the engine in the right amount and at the right time. If the sensor is faulty, it may obtain an incorrect reading of oxygen from the engine exhaust, resulting in poor acceleration.
6. Ignition System Issues
Often, faulty spark plugs or problems with the ignition coil in vehicles can also cause misfires in the engine, resulting in poor acceleration and the vehicle not being able to accelerate properly.
7. Clogged Exhaust System
A blocked exhaust system in any internal combustion engine can restrict the flow of exhaust gases and thereby inhibit the combustion of the fuel in the engine’s internal combustion chamber, causing the engine to struggle to accelerate.
Hence, a blocked or leaked exhaust system can also cause the vehicle to find it difficult to accelerate, and the vehicle may have trouble holding onto speed.
8. Throttle Body Issue
Many times in vehicles, a dirty or worn throttle body can restrict the flow of air to the engine, which can lead to poor acceleration. Because a bad or clogged throttle body can also disturb the fuel/air ratio in the fuel mixture used by the engine’s combustion action.
9. Bad Fuel Injectors
Fuel injectors are also an important part of a vehicle’s engine because they deliver fuel to the engine’s internal combustion chamber. If faulty fuel injectors are at fault, they may not deliver the right amount of fuel to the engine, leading to poor engine acceleration and the vehicle not being able to pick up the right amount of acceleration.
10. Faulty catalytic converter
The catalytic converter also plays an important role in the exhaust systems of vehicles. But in many cases, a faulty or clogged catalytic converter can also severely impair engine performance. This causes the engine to overheat or misfire.
Why is Engine RPM Important?
Engine RPM is an important measurement for the proper operation of a vehicle’s engine and transmission. Engine RPM helps determine a vehicle’s speed, acceleration, and fuel efficiency, allowing every part of the vehicle to function efficiently.
An engine’s RPM range is actually determined by the manufacturer, and engine RPM ranges vary among vehicles depending on the type of engine, its design, and the intended application.
Based on the signal from the engine’s RPM sensor, the vehicle’s ECM sends the proper amount and timing of fuel mixture to the engine and determines the spark timing, allowing the engine to operate efficiently and provide power to the vehicle.
In a manual transmission vehicle, the driver uses the RPM to determine when to shift into a gear, the speed of the vehicle increases as the vehicle is shifted into a higher gear, and the engine’s RPM decreases.
In contrast to vehicles with automatic transmissions, the transmission will automatically shift gears based on engine RPM and vehicle speed. Because the sensor in the automatic transmission helps in changing the gear after measuring the RPM of the engine.
Why Do Some Cars Have Higher RPM Than Others?
Many times there are many questions regarding the RPM of the engine, such as whether the RPM of the engine of some cars is higher than the engine of other cars. The RPM of the engine generally depends on its size. Because often, the RPM of the smaller engine is higher and faster than that of the bigger engine.
Because pistons and other parts are small in small engines, installation is also done in less space. Because of this, the piston of a smaller engine travels faster from bottom to top inside the cylinder in less time.
But in a larger engine, the parts are larger, and the piston travels a greater distance inside the cylinder from bottom to top. For this reason, the larger engine has a lower RPM than the smaller engine.
How To Fix Car Won’t Accelerate But RPMs Go Up
To troubleshoot the Car Won’t Accelerate But RPMs Go Up problem, one must first investigate its cause and then work on fixing it. You can follow the following steps to fix “Car Won’t Accelerate But RPMs Go Up.”
1. Check & Replace Clutch Plate
The most common reason a Car Won’t Accelerate But RPMs Go Up is a worn clutch plate in a manual transmission. Therefore, the first thing to do when this happens is to check the clutch plate of the manual transmission vehicle, if the clutch plate is worn or defective, it should be replaced with a new one.
2. Check & Replace Torque Converter
In automatic transmission vehicles, the torque converter should be inspected when “Car Won’t Accelerate But RPMs Go Up” occurs, and if the torque converter is faulty, it should be replaced by a professional mechanic.
3. Fill Transmission Fluid Full
Transmission fluid is an important component in the operation of automatic transmission vehicles. Because the impeller and turbine in the torque converter transfer the power of the engine to the transmission based on the velocity of the fluid.
But a low transmission fluid level can cause the “car Won’t Accelerate But RPMs Go up” problem. So check the transmission fluid and top up the fluid level if it is low.
4. Replace Bad Fuel Filter
A clogged or bad fuel filter in the engine can also cause acceleration problems. So the fuel filter should be checked, and if it is bad, replace it with a new one.
5. Clean Throttle Body
The throttle body plays an important role in the acceleration of the engine. But in many cases, a bad or dirty throttle body can cause problems with engine acceleration. Therefore, in the case of such a problem, cleaning the throttle or replacing the throttle body should be considered if it is damaged.
6. Clean or Replace Oxygen Sensor
The functioning of the oxygen sensor can directly affect the acceleration of the engine. So always take care of cleaning the oxygen sensor and replace the bad one with a new one.
7. Clean or Replace Fuel Injectors
Bad or clogged fuel injectors in a vehicle’s engine can also reduce acceleration. That’s why you should take care of cleaning the fuel injector from time to time. If the fuel injectors are more severely clogged, replacement should be considered.
8. Check Catalytic Converter
A bad or clogged catalytic converter can be the reason for a vehicle’s engine having acceleration problems. Hence, the catalytic converter should be checked. If the catalytic converter is faulty, it should be replaced with a new one.
Banty is the owner of Autorepairszone.com & is also a vehicle mechanic by profession. We have almost 12 years of experience in the field of automotive repair, and we strive to provide you with accurate information about vehicle malfunctions and repairs based on our experience.