tonyjms2005

Hi all

I noticed a lot of people have removed their secondary air pump and are now faced with the cel illuminated.

If someone with a functional secondary air system could tell me the readings for the front o2 sensor or the AFR I could come up with a circuit that will cost next to nothing.

Thanks

Antony

9krpmrx8

iTrader: (46)

Secondary air pump? There is only one air pump. And what do AFR's have to do with the CEL?

tonyjms2005

The air pump for the secondary air injection system.
Many people have removed due to the fact the bearings go bad and also some people remove the catalytic convertor.

The cel is from the fact that the ECU no longer sees a functioning secondary air system. It uses the front o2 reading to verify that fresh air is being injected into the exhaust system.

I was interested to see what the o2 reading would be when the air injection system is running.

Jastreb

iTrader: (1)

Front O2reads near the high limit when air pump is running. Lambda of 1.39 or 1.40.

9krpmrx8

iTrader: (46)

There are no changes in AFR's regardless of whether the air pump or cat is there or not. All the air pump does is help to light off the cat converter for emissions purposes. At idle your car should be at or near stoich (14.7), regardless of the exhaust setup or if the air pump is there or not.

Jastreb

iTrader: (1)

Once the car is warm, yes it makes no difference in AFR. But when the air pump is running on a cold start, the front O2 reads high because of all the air being thrown at it.

9krpmrx8

iTrader: (46)

Reads high? Lean or rich, not sure what you mean by "high".

Like I said, the AFR's are no different with or without the air pump. I have data logged many cars in addition to min over the past decade. On a stock tune they all act the same way at idle and the ECU's only mission is to achieve and maintain stoich.