1994 LT1 downstream o2 sensor...
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,971
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1994 LT1 downstream o2 sensor...
Noticed it today for the first time. On the passenger side only, there is a post catalytic converter o2 sensor. I only noticed because I had removed the cat chasing down a rattle. I didn't think the OBD I cars used a downstream sensor to monitor the catalytic converter function - thought that wasn't around till OBD II rolled out. It took a breaker bar to remove the sensor! The threads of the sensor were trashed and it looks like the bung in the pipe has slightly damaged threads.
What I am getting at is can I turn off this sensor via a tune? I have tunercat and the 94 LT1 definition file and the hardware to flash it (successfully done for change in gear ratio). If I can simply turn off this sensor and avoid a check engine light then I'll just plug or weld the bung closed and be done with it.
The upstream sensor came right out, no prob.
What I am getting at is can I turn off this sensor via a tune? I have tunercat and the 94 LT1 definition file and the hardware to flash it (successfully done for change in gear ratio). If I can simply turn off this sensor and avoid a check engine light then I'll just plug or weld the bung closed and be done with it.
The upstream sensor came right out, no prob.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
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From: Orlando FL
From my limited knowledge on the subject, you are basically correct on the subject. The 94 PCM has some OBD2 imbedded attributes but can only be seen with certain tools. The on board diagnostics will not show codes for OBD2 but a tech 1 (2) will. Not sure if other scanners will integrate those codes.
But basically the OBD2 codes are not very useful from what I have seen, but only the start of the OBD2 standardization. The down steam O2 sensor does not regulate A/F mixture, but is only a check and feedback as to if it is happy with the exhaust O2 and how the overall engine is doing. There is a write up in the 94 FSM for OBD2 with some additional information.
But basically the OBD2 codes are not very useful from what I have seen, but only the start of the OBD2 standardization. The down steam O2 sensor does not regulate A/F mixture, but is only a check and feedback as to if it is happy with the exhaust O2 and how the overall engine is doing. There is a write up in the 94 FSM for OBD2 with some additional information.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Edit: In just re-thinking this, it might be such that the rear O2 sets the OBD2 code. If thats the case your idea might work. Those codes I mentioned are probably for rich or lean, but I will take a look
Last edited by pcolt94; May 4, 2010 at 08:47 AM.
Burning Brakes
Joined: Nov 2006
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From: Portsmouth Virginia 396LT4 435RWHP/400RWTQ Best so far 11.26 @ 123mph
Rick
