The secondary air injection pump (also referred to as a smog pump or SAI pump) is responsible for lowering the number of carbon emissions that come out of the tailpipe of a vehicle. This is necessary since a vehicle engine is never 100% efficient in the combustion process.
What Does a Secondary Air Pump Do?
The pump lies after the exhaust manifold and before the catalytic converter of the vehicle and it can reduce carbon emissions by pumping fresh air from outside into the exhaust stream. By the time fumes leave the tailpipe, there are fewer hydrocarbon pollutants in them. This promotes a safer environment by cutting down on air pollution outside.
1) Check Engine Light
One of the early symptoms of a bad secondary air injection pump is the Check Engine warning light turning on. The engine control unit can automatically detect when the secondary air injection pump has a problem.
2) Failed Emissions Test
if you have a bad secondary air injection pump, then it means your emissions system will be allowing too many hydrocarbons to be released into the atmosphere. If you happen to live in a state which requires emissions testing, you will fail the test if your secondary air injection pump is bad.
3) Weak Acceleration
A faulty secondary air injection pump will cause problems for the air-to-fuel ratio in your internal combustion engine. If this ratio is too lean (not enough fuel), then your engine will have trouble generating speed whenever you step on the gas pedal.
4) Engine Stalling
You may be driving normally and then suddenly experience engine stalling or hesitation in your vehicle. A secondary air injection pump that is wearing down can cause inconsistent power gaps from the engine.
One minute the power may be fine, and the next the RPM drop too much and the engine shuts off. If the pump is not replaced, the engine may continue to stall at the worst possible times.
5) Low Idle
When your engine is idling, check the tachometer and see what the current RPM is. The normal RPM of an idle engine is somewhere between 600 to 1,000 RPM. But in situations when the secondary air injection pump is not working, you can expect the RPM to drop. This may cause the car to vibrate or even stall as noted above.
If you’ve already experienced engine stalling, poor acceleration, and a check engine warning light, then you need to have the secondary air injection pump checked out immediately.