nfafan

Hello all,
Search doesn't work, so could not research this to see if this has been discussed before.. Anyway...

The Check Eng lite came on. My 99 SE has the Calif ECU box, so I am at the mercy of the dealer's Consult system.
Was told it was the front O2 sensor.
The "rear heated O2" was changed in Oct. Was told at that time that non-premium gas can damage the O2 sensors. Have been running premo ever since then. (Used to use it every other fill-up until the gas crunch hit.)

I find it hard to belive that octane ratings have any effect on the O2. Performance maybe, but the O2?

What is everyone elses take on what I've been told?

Thanks in advance!
Steve

MilesA

Octane is a measure of the fuel's resistance to knock. That is all.

Some brands of Premium fuel have more detergent additives than are present in the Regular grade. Good, keeps things cleaner, but that's all.

The oxygen sensors just measure the amount of oxygen remaining downstream of the combustion process and the catalytic converter.

What you were told is probably a variation of the classic "bad gas" excuse. When a mechanic has no idea what caused a problem, he can always blame it on "bad gas".

nfafan

That's what I suspected too.

Ant96GLE

iTrader: (4)

No, the 02 just reads the exhaust gases... it wouldnt have any direct effect on what type of gas your really using. Depending on your mileage, 02's just tend to die over time. Mine did about a month back and I had to replace all of them

nfafan

the "Bank 2, Sensor 2" O2 sensor - or at least that's what was written on my bill in ink. Was told over phone that it was a "front sensor", and it would cost $350.00 to change it. Told them to forget it.

I read every thread I could find and found a thread pointing to the pics here: http://www.jatan.net/02Sensor1.jpg

Bank 2 doesn't sound like a "front sensor" to me.

Any ideas as to how hard it is to replace the "Bank 2, Sensor 2" - and can I trust the pic in the link as to where it is?

Mine is a Cali spec 99 SE with the 4 connectors up front towards the radiator.

Thanks tons in advance all!

MilesA

The terminology tends to be confusing on these engines. Bank 1 contains cylinders 1, 3, 5. Bank 2 contains cylinders 2, 4, 6. The engine is mounted in the car transversely. Bank 2 is the one closer to the radiator.

The diagram shows the Cali cars. There is an upstream and a downstream 02 sensor for each bank. That is what they are showing on the diagram as front = upstream and rear = downstream. Please read that carefully again. Front does not mean front of the car and rear does not mean rear of the car on this diagram.

Bank 2, Sensor 2 would mean the downstream sensor on the bank closest to the radiator.

nfafan

Thanks! Called the dealer for clarification on the CEL code; P0158 HO2S2 (B2). Told me it was the Bank 2, Sensor 2. Since my car is Cali spec, I suspect that I need to replace the "red harness" O2 sensor.

Any recommendations on brands?
Any gotchas to changing this?

Thanks in advance all for the help!
Steve

Frank Fontaine

Nissan always recommends premium, they do the same thing with the Murano. 87 is required, use premium for best results. You'd think that nissan has a vested interest in premium fuel. Mercedes Benz officially said that since they sell their cars in virtually every country in the world, some of which don't have the various grades of petrol we do, that all of their cars can run on regular. CAN is the keyword.

Anyway, premium is dirt cheap nowadays. It is usually 14 cents more than regular. When regular was 1.099, premium was a full 20 cents more. Don't believe fuel prices are artificial? Sunoco in Southington CT was the same as Sunoco in South Jersey in Dec. Usually CT is a full 22 cents more, that gap evaporated over the last year.