An air pump is an emission component that is one of the most important pieces on a vehicle’s secondary air injection system. Certain vehicles will come equipped with a filter for their emission system air pump. The air pump filter is simply meant to filter the air that is pumped into the vehicle’s exhaust stream through the air injection system. Same as with an engine or cabin air filter, the air pump filter will pick up dirt and dust, and will eventually need to be replaced once it can no longer filter air efficiently.
The air pump filter serves a similar purpose as the engine air filter, however in most cases, it is not as easily accessible for quick inspection and service, as is the engine air filter. The air pump filter serves an additionally important purpose because it is an emissions component, meaning any problems with it can cause the vehicle to have problems with an emissions system, as well as with engine operation. Usually, when the air pump filter is in need of attention, the vehicle will display a few symptoms that can alert the driver that there may be a problem that should be serviced.
1. Engine is running sluggishly
One of the first symptoms that a bad air pump filter may produce is a decrease in engine power and acceleration. A dirty filter will restrict airflow into the air pump which can negatively affect the rest of the system. A dirty or clogged air filter may restrict airflow to the point where the vehicle may become noticeably slower during takeoff and acceleration.
2. Rough and shaky idle
Another symptom of a dirty or clogged air pump filter is a rough idle. An excessively dirty filter will restrict airflow, which may cause an unstable idle that surges. In more severe cases, a clogged air filter may disturb the idle mixture enough to cause stalling when operating the vehicle.
3. Decrease in fuel efficiency
A dirty air pump filter can also have an impact on fuel efficiency. The restriction in airflow from a dirty filter will upset the vehicle’s air-fuel ratio tune, and cause the engine to use more fuel to move the same distance and speed as would be required with a clean, free-flowing filter.
Because the air pump filter can dramatically affect a vehicle’s emissions and performance, it is important to replace this filter at regular service intervals. If you suspect that your filter may be due for a change, or you find that you need one replaced, have a professional technician, such as one from YourMechanic, inspect the car and replace the air pump filter for you.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Air Pump Filter and was authored by Eduardo Ruelas.