02 Sensor Question.

Kingkong0192 · Feb 16, 2014

Just put a new exhaust system on my jeep.

Put a flowmaster 44 and a $80 special hi flow cat.

I drilled a hole in the exhaust pipe after the cat and welded a bung in place.

1. Does the 02 sensor have to be a certain distance away from the cat so it reads correctly?

2. Are the Hi-Flow cats directional? I didn't see any arrows on it to indicate which way it should go. I just welded it in place.

Johnnie Walker · Feb 16, 2014

1. No, as even some that have them pre-installed are in different places. Some install them somewhere in the tube after, so not an issue. It is just reading the efficiency of the cat to make sure it is working. In theory, for offroad only, you could have a "test pipe" and just have the sensor plugged into that.
2. Universal cats are typically plug n pray. Some have arrows, but I doubt it truely matters.

Runnin'OnEmpty · Feb 17, 2014

Only thing I can add is that the bung should be welded
on the upper part of the pipe. This is so condensation
won't collect around the sensor, as it might if the sensor
was located on the bottom of the pipe.

Kingkong0192 · Feb 17, 2014

Thanks for the replies.

@Runnin'OnEmpty, that was literally my exact thought right before i drilled a hole in the exhaust. Except instead of condensation i was thinking something along the lines of soot or something building up on the sensor causing false readings, but now that you mention it condensation does sound way more likely.

Either way it's about 2/3s of the way up the pipe.

Ecomike · Feb 22, 2014

Johnnie Walker said:
1. No, as even some that have them pre-installed are in different places. Some install them somewhere in the tube after, so not an issue. It is just reading the efficiency of the cat to make sure it is working. In theory, for offroad only, you could have a "test pipe" and just have the sensor plugged into that.
2. Universal cats are typically plug n pray. Some have arrows, but I doubt it truely matters.

I suspect Cats do have an inlet side, as I know they have a different catalyst mix on the inlet area than the downside area, so a properly built Cat, should have an inlet.

02 Sensor Question.

Kingkong0192

NAXJA Forum User

Johnnie Walker

Piece of Fish!

Runnin'OnEmpty

NAXJA Forum User

Kingkong0192

NAXJA Forum User

Ecomike

NAXJA# 2091

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