In the past, when a driver was driving up a hill, with an extra load in the back of their vehicle or they just turned on the AC, their right foot was the only way to increase their speed. As technology has improved and more vehicles transitioned from the manual throttle cable to electronic throttle controllers, there have been multiple improvements to the fuel system that increases engine efficiency and driver comfort. One of these components is the throttle kick actuator. Although this is an electrical actuator, it can become faulty, which will require it to be replaced by a certified mechanic.
What is the throttle kicker actuator?
A Throttle Kicker Actuator is a component of the throttle control which helps to regulate throttle control in situations where additional throttle is needed suddenly or when there is a sudden drop in throttle needed. When there is a sudden release of the accelerator pedal, the throttle kicker actuator serves to gradually slow engine speed rather than allowing a sudden drop. A throttle kicker actuator also helps to maintain certain throttle positions when additional load or strain is put on an engine such as using various vehicle accessories like AC, engaging the PTO system on a truck with an onboard welding system, or even operating the lift feature on a tow truck.
The throttle kicker actuator can be operated electronically and by vacuum. In a vacuum operated setting, the actuator opens the throttle slightly to increase air/fuel flow. An idle speed control actuator is controlled by an idle speed control actuator solenoid. This solenoid is controlled by a control module. When this solenoid is turned off, no vacuum is routed to the idle speed control actuator, allowing it to open the throttle slightly to increase idle speed. In order to decrease idle speed, this solenoid is turned on, routing vacuum to the idle speed control actuator, allowing the throttle to fully close.
Like most mechanical parts built on vehicles these days, the throttle kick actuator is designed to last the entire lifespan of a vehicle. However, it is susceptible to wear and tear and can become damaged, faulty or broken. If this occurs, it will cause a few symptoms to be recognized by the driver, alerting them that a potential issue with the throttle kicker actuator exists and that it may need to be replaced.
1. Throttle hesitation
Most of the time, the engine responds to throttle pressure applied by the driver without stumbling or hesitation. However, when the throttle kicker actuator is damaged, it can send inaccurate readings to the ECM and cause more fuel to be sent inside the motor than air. In this case, a rich situation is created inside the combustion chamber, which can lead to the engine delaying igniting the fuel/air mixture. The kicker actuator is typically the component on an electronic fuel injection system that will display this symptom when a sensor is damaged and needs to be replaced.
2. Poor fuel economy
Similar to the issue above, when the kicker actuator is sending bad information to the onboard computer, the air to fuel ratio will be inaccurate. In this case, not only will the engine stumble, but it will consume more fuel than it should. A side effect of this situation is that the unburnt fuel will exit out of the tailpipe as black smoke. If you notice that your car is blowing black smoke and your fuel economy has reduced significantly in recent days, contact a mechanic so they can diagnose the issue and replace the throttle kicker actuator if necessary.
3. Engine stalling often
In some cases a damaged throttle kicker actuator will impact the idle ability of the engine after it has been under a load. When the idle goes too low, the engine will shut off or stall. In some cases this is caused by an actuator that is not working at all, which means that a mechanic will have to replace it soon in order to get your engine back running the way it should. On most new cars, trucks, and SUVs, a failure with the throttle kicker actuator will cause an OBD-II error code to be stored in the ECU. If you notice any of the above symptoms, or think you may have a problem with your throttle kicker actuator, contact a local ASE certified mechanic so they can download these error codes and determine the right course of action to get your car back running the way it should.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Throttle Kicker Actuator and was authored by Timothy Charlet.