Car won’t accelerate, but RPMs go up, is a serious issue commonly seen in older vehicles. RPM refers to the rotational speed of the engine, and encountering this problem can indicate underlying issues. Often, as vehicles age or due to problems related to the engine and transmission components, the car’s speed fails to increase while the RPM rises. Repairing or replacing these parts can also be a costly task.
In this article, we will explore the main reasons why your car won’t accelerate, but RPMs go up, along with methods to diagnose and troubleshoot this problem effectively.
What is Engine RPM?
RPM (Revolutions Per Minute) is a scale to measure the rotational speed of the crankshaft of any engine. It measures how many times the engine’s crankshaft rotates in a minute. It is displayed by the RPM gauge in the cluster meter mounted on the vehicle’s dashboard.
Some vehicles have this gauge with a needle that moves up or down according to the engine speed, while modern vehicles have a digital RPM gauge that shows the RPM in numerical form. RPM plays an important role in the efficient operation of the engine and transmission, as many functions and performance 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 a car won’t accelerate, but RPMs go up, is a worn clutch or a faulty torque converter. This happens because, during acceleration, the engine RPM increases, but if the transmission begins to slip, it prevents power from being efficiently transferred to the wheels, resulting in poor acceleration.
Additionally, causes may include low or contaminated transmission fluid, improper lubrication, transmission slipping, transmission solenoid or sensor malfunction, and a clogged catalytic converter.
Let’s look at these potential causes in detail one by one.
#1. Worn Clutch Plate
Often, in a manual transmission car, a worn clutch can also cause the car not to speed up but the RPMs increase, as the worn clutch plate keeps slipping along the engine’s flywheel during acceleration, causing the engine to lose power over time. Power is not reaching the wheels, which may cause the RPMs to increase during acceleration, but the car will not pick up speed. This problem also increases fuel consumption.
#2. Failed Torque Converter
The torque converter is a vital part of an automatic transmission. In automatic transmission vehicles, the torque converter is the only device that transmits the engine power to the vehicle’s wheels without the need for a clutch. But in an automatic transmission car, the failure of the torque converter may also not increase the speed of the car but the RPMs increase, causing symptoms similar to the clutch slipping in a manual car. A failed torque converter may also not accelerate the vehicle but the RPMs may increase.
#3. Transmission Low Fluid Problem
In automatic transmission vehicles, the torque converter works with the transmission fluid. But low automatic transmission fluid level may also not increase the speed of the car but the RPMs may increase. This can cause problems, as low transmission fluid affects the operation of the impeller and turbine in the torque converter. Therefore, low transmission fluid may also cause the vehicle to not accelerate properly.
#4. Faulty Fuel Filter
In many cases, a faulty fuel filter also hinders the acceleration of the vehicle. This is because the engine needs more fuel during acceleration. But a 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 sends it to the vehicle’s ECM. Based on this signal, the vehicle’s ECM sends the fuel mixture to the engine in the right amount and at the right time. If the sensor is faulty, it may get an incorrect reading of oxygen from the engine’s exhaust, resulting in poor acceleration.
#6. Ignition System Problems
Often, faulty spark plugs or ignition coil problems in vehicles can also cause misfires in the engine, resulting in poor acceleration and the vehicle is unable to pick up speed properly.
#7. Clogged Exhaust System
A blocked exhaust system in any internal combustion engine can restrict the flow of exhaust gases and thus impede the combustion of fuel in the engine’s internal combustion chamber, causing difficulty for the engine to pick up speed. Therefore, a blocked or leaking exhaust system can also cause the vehicle to have difficulty picking up speed, and the vehicle may have trouble maintaining speed.
#8. Throttle Body Problems
Many times in vehicles, a dirty or worn throttle body can restrict the flow of air into the engine, causing poor acceleration. Because a worn 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 a vital part of a vehicle’s engine as they deliver fuel to the engine’s internal combustion chamber. If the faulty fuel injectors are malfunctioning, they may not deliver the right amount of fuel to the engine, causing poor engine acceleration and the vehicle may not be able to pick up the right amount of acceleration.
#10. Faulty Catalytic Converter
The catalytic converter also plays a vital role in the exhaust system of vehicles. But in many cases, a faulty or clogged catalytic converter can also seriously impair the engine’s performance. This causes the engine to overheat or misfire.
#11. Bad Turbocharger
If your vehicle’s engine turbocharger is bad or has a boost pressure leak, your car will have a problem like the car’s speed will not increase but the RPM will increase. Because a bad turbo directly affects the engine’s performance, you will get high RPM during acceleration but the speed will feel low.
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.
#9. Inspect Turbocharger
If your car won’t accelerate but RPMs rise, related to the turbocharger, inspect the system for boost leaks or damaged hoses and tighten connections. Clean or replace clogged turbo components. Ensure the wastegate functions properly and recalibrate sensors. Perform a diagnostic scan to identify and resolve underlying issues.
Why is Engine RPMs Important?
Engine RPMs is a critical measurement for the proper operation of a vehicle’s engine and transmission. Engine RPM helps determine vehicle speed, acceleration, and fuel efficiency, allowing every part of the vehicle to work efficiently. The engine’s RPM range is actually determined by the manufacturer, and the engine RPM range varies between 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 the fuel mixture to the engine and determines the spark timing, allowing the engine to work efficiently and power the vehicle. In a manual transmission vehicle, the driver uses RPM to determine when to shift into gear, the vehicle’s speed increases as the vehicle shifts into higher gears, and the engine’s RPM decreases.
Unlike vehicles with automatic transmissions, the transmission will change gears automatically based on the engine RPM and vehicle speed. Because the sensor in the automatic transmission helps to change gears after measuring the engine’s RPM.
Why Do Some Cars Have Higher RPM Than Others?
Many times there are many questions about the RPM of the engine, such as whether the RPM of the engine of some cars is higher than the engines of other cars. The RPM of the engine usually depends on its size. Because often the RPM of a small engine is higher and faster than that of a large engine.
Because the piston and other parts in a small engine are smaller, the installation also takes up less space. Because of this, the piston of a small engine travels quickly from bottom to top inside the cylinder in a short time. But in a large engine, the parts are larger and the piston travels a longer distance from bottom to top inside the cylinder. Because of this, the RPM of a large engine is lower than that of a small engine.
Conclusion
If your car won’t accelerate but RPMs go up, this common problem could be caused by a variety of reasons, including a worn clutch plate or bad torque converter, bad throttle body, clogged fuel filter, bad sensors or transmission-related problems.
To diagnose and fix the problem, start by checking error codes, inspecting the throttle body, ensuring proper fuel delivery and testing transmission components. Ignoring it could lead to more serious damage.
FAQ’s
why is my car jerking when i give it gas?
If your car jerks when pumping gas, possible causes could be a faulty axle or driveshaft, clogged fuel injectors, faulty spark plugs, a bad mass airflow sensor, or a problem with the transmission.
Why doesn’t my car go over 30 mph?
If your car won’t go over 30 mph, possible causes could be problems with the fuel system, transmission, or engine. However, in many cases, there may also be electrical or sensor-related problems.
