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Showing results for tags 'O2'.
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Additional info required: A while ago (like a year or more) there were some threads floating around about O2 sensor voltage readings in the 3+ volt range on diagnostic scanners. I don't recall there being a clear answer as to the reason at the time. I have had some O2 sensor issues recently so I went digging for info and basically found that the reason for the trouble was that I bought the wrong type of sensor. I bought an O2 sensor, when what I needed was an Air/Fuel Ratio sensor. The problem was on a Toyota, but the same principles of how the sensors differ apply to every brand of vehicle. The link below comes from a website we use in school, and has tons more info about various sensors and their functions, as well as dozens of other tech articles that can be useful during diagnosis of a problem. What my issue boiled down to is the ECU was getting a reading of incredibly lean mixture from the O2 sensor. Because on an O2 sensor rich = high voltage and lean = low voltage. but wih an A/FR sensor its the opposite, rich = low and lean =high. The ECU would add more fuel and get a rich voltage back rom the sensor,except the ECU is programmed to read high voltage as lean, even though the sensor was responding as it should. And so the cycle repeats itself until the ECU can no longer adjust, which in this case pegged the Long Term Fuel Trim at 44.5%. But back to the point, if you get oxygen sensor voltage reading in the 3V range on a scanner, its because you have an Air/Fuel Ratio sensor, which gets supplied a reference voltage of 3.3V from the ECU. The sensor then bumps up (if lean) or bumps down (if rich) the return voltage signal back to the ECU. Some ECUs convert scanner output to a normal O2 sensor output voltage to avoid confusion, but not all. Be sure of what you have before purchasing a replacement sensor. http://www.autoshop101.com/forms/h37.pdf
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I just bought a used 1998 Legacy 2.2 5spd MT with ~169,000 miles on it. I'm looking for replacement knock and downstream O2 sensors for it. For the O2 Sensor, I am looking at the Bosch 15726. Is this a good sensor or should I go with the more expensive OEM part? For the knock sensor, I have not yet found a suitable part. Are there any non-OE parts or should I stick with OEM?
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I received the following 2 codes late last year: P0030 Heated oxygen sensor heater control circuit Bank 1 Sensor 1 & P0134 Oxygen sensor circuit no activity detected Bank 1 Sensor 1 After resetting the codes about 2 or 3 times, I replaced my Upstream O2 Sensor. No issues until just recently. Only this time I got the P0134 code alone. Either way, it's pointing me to the same O2 Sensor I just replaced. Before I purchase another, more expensive O2 Sensor - are there any other areas 'pre-upstream sensor' I should be looking in to? Sidenote 1 When the code popped up most recently, I removed the Sensor and cleaned with a wire wheel and replaced. Checked all contacts for resistance and continuity. Everything looked good and about 2 days later the CEL went out and didn't come back for about a month (where I'm at now). Sidenote 2 I burn a full quart of oil in between Oil changes (every 4,000 mi.). I mention this because I worry I may have the beginning signs of an internal head gasket leak (oil transfer between galleys and cylinders) which may jack up my combustion and fowl up O2 sensors. Just a thought though, I can't be sure of this as there seems to be no smoke from the rear at start up. Regards,
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- oxygen sensor
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I have been chasing the cause of extreme surging with this car. It was a bad O2 sensor. So as a quick heads up, most people will tell you its not possible for that to be the cause, but trust me it was. With the new O2 sensor it was running much better (solved the extreme surging) but with some slight hesitation and almost a miss. Later in the day I am pretty sure I found the source of the hesitation/miss... Timing belt that decided to break on my way to show off the car to a buddy. Hopefully the new timing belt will take care of the last remaining problems. But let me digress, I had a fun time changing the O2 sensor on the newly purchased 1993 Subaru Loyale. After many trips to the store to grab different tools and things I ended up getting the O2 sensor out. At first I spent some time attempting to use a harbor freight O2 sensor removal tool but just managed to figure out that its a bit tight to make that tool work and once you have figured out a way to make it work... its a 22mm O2 sensor and not a 7/8 like the harbor freight tool. Ok run to the local autozone and rent there O2 tool kit (25.99). Throw on the 22mm O2 sensor tool and manage to fight the sensor for another 30+ minutes before saying screw it and removing the whole y-pipe. Once the y-pipe was out I managed to finish rounding off most the existing O2 sensor and was ready to take to my friends metal shop to just drill it out. Then I had one last idea, remove the heat shield and see if I could fit a box end on the O2 sensor that way. Magically it worked. I could fit a 22mm box wrench on the O2 sensor and with some help of a rubber mallet I was able to break free the O2 sensor from the exhaust. It was a bitch but I am pretty sure this was the only way I would have been able to remove the O2 sensor and also the most simple fool proof way to do it. tl;dr Remove the y-pipe. Once thats free remove the heat shield around the cat. Use a 22mm wrench and a rubber mallet to beat the O2 sensor out of the cat. Tools Needed: 12mm, 14mm, 22mm, rubber mallet, PB blaster (or something of the sort), rags. Hope my pain is another mans gain.
- 22 replies
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- O2
- Oxygen Sensor
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I bought this Subaru about 2 weeks ago for a couple hundred bucks on a rainy dark night. Ran, shifted, and stopped just fine. Bought it and drove it around until i had to registar it. Then i started poking around. To the point: Can somebody provide me with a picture of the o2 sensor plug/location? I have been tracing wires on and off for a while and cant seem to find where the o2 sensor connects into the harness. The wires coming off of the sensor itself have definitely been cut off, but i wouldnt this they would have cut the harness as well... Im starting to wonder if the previous owner chopped it off when they swapped in a new engine. (Still an ea82 Spfi) Much appreciated.
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Hi all, have had issues with my 02 plate GX (yep turbos are too much for me to handle ) which long story short I've narrowed down to being pre-cat o2 sensor - problem is all the tech manuals i can find are fairly vague about parts for the GX (it looks like it's the b*d child of every other model in the range!) so I can't quite work out the part number for the front lambda - any ideas? the ones suggested always seem to have the wrong connector (mine has a white box shaped connector) any help much appreciated