Oxygen Sensor question

sullione · Post by **sullione** » Sun Mar 02, 2003 10:46 pm

Hello all, I need some help. I was driving my 91 Legacy LSi and the CEL came on. It then went off after about a minute and the car never behaved any differently when it was on or off, it still drove smoothly. I just got around to pulling the code and it was for the oxygen sensor. My question is 1. is my oxygen sensor bad? and 2. if it is, why did the CEL go out? Please help.

entirelyturbo · Post by **entirelyturbo** » Mon Mar 03, 2003 1:01 am

If it didn't run any different then I wouldn't worry about it. We only have one O2 sensor, which helps in determining the proper a/f mix, so if it was really bad, your car would run differently. It went out coz it was probably a glitch. Pull the battery cable for 30sec and then drive it again, should have no other problems...

vrg3 · Post by **vrg3** » Mon Mar 03, 2003 4:10 am

OBD 1 Subaru engines don't have to depend too heavily on the oxygen sensor. I once disconnected my oxygen sensor to see what would happen, and ... well, nothing happened. The engine ran perfectly fine in open-loop mode all the time. It didn't even illuminate the CEL until I did a D-check.

I'd say to first check the connections to the oxygen sensor, do a clear memory procedure, and then do a D-check procedure. If the D-check doesn't find any problems, then chalk it up to some kind of weird transient problem. If it gives you the oxygen sensor code again, then your sensor might be bad.

Even if your sensor is bad, it's not that big a deal (until it's time for an emissions inspection, of course). :)

ciper · Post by **ciper** » Mon Mar 03, 2003 7:38 pm

Your sensor may be slowly going dead. Im pretty sure the light will illuminate if either

Open or Short
Reading out of range for a specified amount of time.

legacy92ej22t · Post by **legacy92ej22t** » Tue Jul 29, 2003 2:02 am

I have a different question.I'm putting on my turbo back next week and the o2 bung is on the high flow cat inbetween the dp and midpipe,not the dp.Is this ok or should I go through the trouble of drilling a new bung in the dp and capping the one in the cat?Thanks

vrg3 · Post by **vrg3** » Tue Jul 29, 2003 2:15 am

"On" the high flow cat?

It's gotta be either before or after the cat...

You'll probably be fine if the sensor bung is before the cat. If it's after the cat you'll need to put a bung in before it, since the cat cleans the exhaust up resulting in a lean reading.

If you want to get oxygen sensor bungs really cheap, go to an auto parts store and pick up a "spark plug non-fouler." Spark plugs have the same threads as oxygen sensors. You can just cut off the portion you don't need and weld it right on.

legacy92ej22t · Post by **legacy92ej22t** » Tue Jul 29, 2003 2:20 am

Sorry its right before the cat,It's just on the cat portion of the exhaust just behind the flange that attaches to the dp.

vrg3 · Post by **vrg3** » Tue Jul 29, 2003 2:23 am

Ah, cool... In that case, it should be okay, especially since our oxygen sensors have built-in heaters. I'd suggest you replace your sensor if it's old, though, just to make sure the readings aren't too lazy.

legacy92ej22t · Post by **legacy92ej22t** » Mon Aug 04, 2003 5:22 am

I was just going through the install directions for my turboback and the bung is on the output of the cat because it's for the wrx. I guess I really should put a bung in the dp and keep the o2 sensor in the stock location. I really hate to drill a hole in my dp though

ciper · Post by **ciper** » Mon Aug 04, 2003 5:36 am

Why do you worry about drilling the DP? I have a downpipe that will be cut welded and drilled before even installing it on a vehicle!

legacy92ej22t · Post by **legacy92ej22t** » Mon Aug 04, 2003 5:45 am

It's probably silly to care, gotta do what works, I just want it to look as clean and nice as possible at the end thats all. The shop doing the work for me can't tig weld only mig weld so it may look a little rough too. I'm also a little bummed because I already went through the trouble of finding another o2 wiring harness and 22 gauge wire to extend the sensors location.

ciper · Post by **ciper** » Mon Aug 04, 2003 5:51 am

Probably the best place for you would be on towards driver/transmission right after the bend. It would be hidden from below and above.

Instead of getting another harness and wire why not just use the NA Oxygen sensor? It has a longer wire right? Or even better order the universal one from oxygensensors.com and just cut the wire from your current one right at the edge of the sensor.

legacy92ej22t · Post by **legacy92ej22t** » Thu Aug 07, 2003 5:34 am

It ended up that my cat flowed either way so we just turned it around. What we did to lengthen my o2 line was to get the female connector off of an o2 sensor and the male off the wire harness on a wreck. Then got some 22 gauge wire, wired them together and plugged in each end. So it has a double connection...works real good no CEL's

vrg3 · Post by **vrg3** » Thu Aug 07, 2003 7:18 am

legacy92ej22t wrote:What we did to lengthen my o2 line was to get the female connector off of an o2 sensor and the male off the wire harness on a wreck. Then got some 22 gauge wire, wired them together and plugged in each end.

Yeah, that's the best way to alter your wiring... Get the stock connectors and make it plug and play.

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Oxygen Sensor question

Oxygen Sensor question