Ever since I had a new exhaust system put on my 1989 FJ62 it has idled a bit rough and runs different. I can't qualify different other than at 2300 rpm's it seems to have a small boost in power. For some reason I had always suspected that the two o2 sensors had been placed in the wrong exhaust pipes. I finally checked tonight and it appears that the exhaust pipe for the forward bank of cylinders has the o2 bung and sensor for the rear bank of cylinders and vice-a-versa.

So the $64k question is does anyone know if the computer knows the difference if it is getting front bank info from the rear bank o2 sensor and vice-a-versa? I would think that it would, hence the two different sensors, yet I'm not sure how the computer works.

Thanks...Don

swap the wires and take it for a test drive.

Is the 3F batch or individual fire??

I am thinkin batch. If it is batch it would not matter.

o2 sensor location is too far apart to allow switching wires. I don't know if the 3FE is batch or individual fire 9not sure what you mean by batch or individual fire).

Tahnks...Don

batch = all injectors fire at once.

Individual fire means they fire independantly.

How would you think the sensors got installed wrong if the wires won't reach the other location???

:confused:

there are 2 o2 sensors for each side of the engine. one forward and one rearward which should be place after the cat converter. The forward sensor is necessary for the computer as it give the correct signals on air/fuel mixture etc. The rear o2 sensor is not necessary from a proper running standpoint, it really just gives the computer info on whether or not the cat is doing it's job cleaning up the air that is put through the cat. You can use o2 simulators, they work great, but of course are not smog legal. I don't have to worry about smog. You could however though buy plugs for the rearward o2 sensors, plug them and use the simulators during regular use and then disconnect the sims and plug in some o2 sensors for smog. You live in San Diego? I see clairemont. I am in north county SD. What type of engine are you running? Let me know if you have other questions.

Noah

there are 2 o2 sensors for each side of the engine. one forward and one rearward which should be place after the cat converter. The forward sensor is necessary for the computer as it give the correct signals on air/fuel mixture etc. The rear o2 sensor is not necessary from a proper running standpoint, it really just gives the computer info on whether or not the cat is doing it's job cleaning up the air that is put through the cat. You can use o2 simulators, they work great, but of course are not smog legal. I don't have to worry about smog. You could however though buy plugs for the rearward o2 sensors, plug them and use the simulators during regular use and then disconnect the sims and plug in some o2 sensors for smog. You live in San Diego? I see clairemont. I am in north county SD. What type of engine are you running? Let me know if you have other questions.

Noah

The scenaio you describe sounds more like a OBDII scheme. I'm running a stock 3FE. One sensor is for the forward three cylinder and the other sensor is for the rear three cylinders. Both o2 sensor are pre cat in location.

don