Engine Light - System Too Rich - bank 1

I have a 97 Venture. It worked great up to 2003 and different problems start to show up. Anyway.

Recently, I have the Engine Light ON and the code is "System Too Rich - Bank 1". Since I just changed the gas two days ago, I put in my regular gas from ESSO and have the computer reset. The light is off for a month. Now it is back again this morning. I have a question.

With the previous code of "System Too Rich - Bank 1". It is likely the Oxygen Sensor is bad. There are two Oxygen sensor (front and rear) in the car. Which one is related to "Bank 1".

Thanks
Derek

Bank 1 (as oppose to Bank 2) means the first oxygen sensor for vehicles that have two sensors upstream sensors. Some V6/8/10s have two independent exhaust systems, or the sensor is upstream where the two manifolds are combined. Bank 1 is associated with the manifold that is used for cylinder 1. Bank 2 would be for the other one.

Our vans only have 1 upstream sensor, located just after the two manifolds attach to the exhaust downpipe, before the cat. This would be the sensor for bank 1.

The other sensor is the downstream sensor bank 1. It is only used to measure the efficiency of the cat converter. It does not get used in any way in the engine management system for calculating fuel mixture. When that one goes south, a different DTC is set.

Thanks for the reply. Great info. Just one more question. I was learned that fuel pressure and leaking injector can also cause Rich O2 sensor reading. In other words, the O2 sensor may be OK but fuel pressure is an issue. I t appears that I do not have the Engine Error Code when I drive with full tank of gas. When the remaining gas is only 1/4 and after driving for 30 minutes, I have this error code.

Any idea how to check fuel pressure or leaking injector.



Bank 1 (as oppose to Bank 2) means the first oxygen sensor for vehicles that have two sensors upstream sensors. Some V6/8/10s have two independent exhaust systems, or the sensor is upstream where the two manifolds are combined. Bank 1 is associated with the manifold that is used for cylinder 1. Bank 2 would be for the other one.

Our vans only have 1 upstream sensor, located just after the two manifolds attach to the exhaust downpipe, before the cat. This would be the sensor for bank 1.

The other sensor is the downstream sensor bank 1. It is only used to measure the efficiency of the cat converter. It does not get used in any way in the engine management system for calculating fuel mixture. When that one goes south, a different DTC is set.

Fuel pressure can be checked at the test port on the rear fuel rail. It looks like a tire valve and is usually covered with a black cap. If you look behind the PS pump you'll see it. You can get a test guage at any autoparts store for probably around $20. Some places like Autozone may let you rent the test guage.

I'm not sure how to test for a leaky injector.