What is Toyota secondary air injection system?

To decrease the level of emissions emitted from the tailpipe, the Pulsed Secondary Air Injection (or Air Suction) system is used to introduce air into the exhaust flow, thereby allowing combustion to continue well into the exhaust system.

How do you know if your secondary air pump is working?

The secondary air pump has to start audibly after a cold start of the engine. Start vehicle engine. If the power supply of the secondary air pump is fine, but the secondary air pump runs with a scraping, whistling or scratching noise or not at all, the secondary air pump is to be replaced.

Does the secondary air pump run all the time?

As a result, the secondary air pump was energised for an impermissibly long period of time. During a cold start, the secondary air pump may only be in operation for a maximum of 90 – 120 seconds. The secondary air pump is not designed for continuous use!

How does pulse air injection work?

Pulse Type: The pulse type system uses vacuum to draw fresh oxygen into the air injection system. This vacuum is created by the exhaust gases as they travel down the exhaust passages at a high rate of speed.

How does an aspirated air injection system work?

Aspirated air injection. Air injection can also be achieved by taking advantage of the negative pressure pulses in the exhaust system at engine idle. A sensitive reed valve assembly called the aspirator valve is placed in the air injection pumping, which draws its air directly from the clean side of the air filter.

When was the secondary air injection system introduced?

Secondary air injection (commonly known as air injection) is a vehicle emissions control strategy introduced in 1966, wherein fresh air is injected into the exhaust stream to allow for a fuller combustion of exhaust gases.

When does the air injection point become the upstream injection point?

The original air injection point became known as the upstream injection point. When the catalytic converter is cold, air injected at the upstream point burns with the deliberately rich exhaust so as to bring the catalyst up to operating temperature quickly.

Why is there a check valve in the air injection system?

A check valve prevents exhaust forcing its way back through the air injection system, which would damage the pump and other components. Carbureted engines’ exhaust raw fuel content tends to spike when the driver suddenly releases the throttle.