O2 Sensor question!
Thread Starter
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
O2 Sensor question!
Just have a quick question on o2 sensor readings. After installing my new hooker headers I noticed the car not running properly, and a couple of SES lights.
Hooking up my scanner I had several codes all related to the right o2 sensor. (Right o2 sensor lean, engine lean condition, right o2 sensor error)
Watching the voltage reading on this sensor while the car was running, it would sit at a dead 44 mv , it would not oscillate or move as it should. Simple , dead sensor, swap it out.
Now after two weeks of running the car, the new sensor reads that the engine is very lean on the right side. It will actually oscillate but not in the range it should, it will only oscillate 50-100 mv.
Now my question is this: Would not resetting the computer after swapping the sensor out damage the new sensor in anyway (IE if the car continued to run PIG RICH on that side?).
The car runs and drives fine, it is just reading a very lean mixture on the right side. Wiring has been checked, new plugs, new wires, brand new MSD Opti ect ect.
I cannot find or think of any reason this should be happening, unless by some chance I got a bunk sensor.
Any thoughts or suggestions would be great.
The car is a 92 A4 btw.
Thanks!
Hooking up my scanner I had several codes all related to the right o2 sensor. (Right o2 sensor lean, engine lean condition, right o2 sensor error)
Watching the voltage reading on this sensor while the car was running, it would sit at a dead 44 mv , it would not oscillate or move as it should. Simple , dead sensor, swap it out.
Now after two weeks of running the car, the new sensor reads that the engine is very lean on the right side. It will actually oscillate but not in the range it should, it will only oscillate 50-100 mv.
Now my question is this: Would not resetting the computer after swapping the sensor out damage the new sensor in anyway (IE if the car continued to run PIG RICH on that side?).
The car runs and drives fine, it is just reading a very lean mixture on the right side. Wiring has been checked, new plugs, new wires, brand new MSD Opti ect ect.
I cannot find or think of any reason this should be happening, unless by some chance I got a bunk sensor.
Any thoughts or suggestions would be great.
The car is a 92 A4 btw.
Thanks!
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
Not resetting the computer shouldn't have harmed the new sensor. Do '92's have heated O2 sensors from the factory? If not, the sensor might not be heating up enough to read properly since it's moved downstream a bit now (unless you installed shorties). If you extended the wire on that side, you may want to doublecheck the connections too.
Thread Starter
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
Not resetting the computer shouldn't have harmed the new sensor. Do '92's have heated O2 sensors from the factory? If not, the sensor might not be heating up enough to read properly since it's moved downstream a bit now (unless you installed shorties). If you extended the wire on that side, you may want to doublecheck the connections too.
The sensors on 92's are single wire unheated.
It did not change location as I did indeed install shortie headers.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
You could try swapping the O2s from side to side to see if its a sensor problem or the car really is lean on one side.
Also, try holding the engine at say 2,000-2,500RPM while reading the sensor valve to see if it's running too cold at idle.
Thread Starter
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
Most of the sensor readings I have done have been 1500-2500rpm while driving the car.
I have a brand new sensor I will be installing ina few hours after work.
Thread Starter
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
O2 Sensor problem RESOLVED
Got it fixed last night. Turns out there was an exhaust leak at the ball flange where the shortie header meets the turn down pipes. This was allowing fresh air to be sucked into the exhaust stream and causing the o2 sensor to read dead lean.
Tightened everything up and the car drives like a dream
Tightened everything up and the car drives like a dream
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Got it fixed last night. Turns out there was an exhaust leak at the ball flange where the shortie header meets the turn down pipes. This was allowing fresh air to be sucked into the exhaust stream and causing the o2 sensor to read dead lean.
Tightened everything up and the car drives like a dream
Tightened everything up and the car drives like a dream
Jake
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