99obw Posted November 12, 2003 Share Posted November 12, 2003 I just pulled the 145k mile old oxygen sensor off of the 99 outback. A little difficult but easier for me from underneath. I had to get the exhaust really hot to get it out. Once the sensor was out I noticed that the universal replacement they sent me is a 3-wire and the OEM Bosch is a 4-wire. DOH! The missing wire is a ground. Will the 3-wire work reliably over the next couple of years, taking into account salt and lots of driving? I know a lot of other makes did or still do ground their sensors through the exhaust. The paperwork with the sensor shows three different connector types for subaru 3-wire sensors but no 4-wire. Maybe the diagrams for the subaru 4-wire sensors are in the paperwork for the 4-wire universal replacement. .:madder: Off to finish the oil change, snow tire mounting, headlights, and fluids. Eagerly waiting for the voice of experience. PS: I need to fix that !@#$ noisy exhaust shield too Quote Link to comment Share on other sites More sharing options...
99obw Posted November 12, 2003 Author Share Posted November 12, 2003 I put the O2 sensor back for now. I will wait until I hear some advice on that before I do anything. I think I finally have the rattle fixed (3rd try) on the pipe in front of the front cat. I fed 2 hose clamps between the shield and the pipe and around the other side of the shield and tightened them up. I was mounting the nice blizzaks I bought from gbhrps when I noticed the left rear strut had collapsed!!! The spring had pushed the cone shaped spring support into the tire. Salt is my automotive nemesis. Luckily I have the parts to do the rear struts sitting in the shop. I hate to think of what could have happened had the spring punctured the tire. I feel like this was a disaster narrowly averted. The new struts, springs, and strut mounts go on tomorrow. Quote Link to comment Share on other sites More sharing options...
Hocrest Posted November 12, 2003 Share Posted November 12, 2003 I don't remeber the details but there was a recall issued dealing with rust and springs/struts?? You may want to check that out before replacing them on your own. Quote Link to comment Share on other sites More sharing options...
99obw Posted November 12, 2003 Author Share Posted November 12, 2003 Thanks Dave. I think that was for the spring. I will look into that. Regardless, the car has 145k miles and they were in need of replacement, and I have the parts, so I am going to do it tomorrow. I don't have the time nor the patience for dealing with a dealer. It really makes me question the safety of the front struts. Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted November 12, 2003 Share Posted November 12, 2003 Definitely get a 4-wire. 3-wire sucks. I actually just replaced my 3-wire OEM with a 4-wire generic from oxygensensors.com. I would highly recommend you go that route, or replace it with an OEM O2 sensor. Whatever you do, make sure you keep the 4-wire sensor. I put it in last night, and I don't think my car has ever idled as good as it does now. I didn't try and measure the potential difference between where the O2 sensor mounts and a good ground point, but considering the bolts to the heads & the bracket on the back of the tranny are pretty much it in terms of completing the grounding circuit. I know all of my exhaust is rusted to hell, including the head bolts. The only & last option I would consider is getting an additional wire and clamp it to the body of the O2 sensor & then run that to the extra ground wire. But it sounds like they sent you the wrong part, so just send it back for the correct part. Also, at least for my car, the stupid generic instructions they had for the wiring was pretty much incorrect for my car. I used the pin-outs in my FSM to know what wires to connect to what. Quote Link to comment Share on other sites More sharing options...
99obw Posted November 12, 2003 Author Share Posted November 12, 2003 Thanks Josh. I ordered them from oxygensensors.com. I am dissapointed that I recieved 3-wire sensors for both my 99 outback with a 2.5l and my friends '97 legacy wagon with a 2.2l. They sent me the correct 4-wire sensor for my POS '92 dodge though. I am going to send them back. Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted November 13, 2003 Share Posted November 13, 2003 yeah....send it back.....tell them you want the 4-wire sensor. Quote Link to comment Share on other sites More sharing options...
jcniest5 Posted July 27, 2004 Share Posted July 27, 2004 I've just finished replacing the oxygen sensor on my 91 Legacy. If you are getting the universal sensor, better read my discovery. What I've found out was that the wires color may not necessary be (correspondant to) what everybody mentions elsewhere on this forum. Black doesn't always go with black. And the same holds true for white with white. To make the story short, I found that the signal/output wire on my old sensor is the White wire, not the Black or Purple as the included instructions said. Once the proper signal/output wire is found, the two other wires are the heater/heated wires (and polarity is not important) so the rest of the installation or wire splicing will be easy. If anyone needs to know how I discovered which wire is which (on the old sensor only as there is instruction with the new one), please ask. Quote Link to comment Share on other sites More sharing options...
Olnick Posted March 5, 2005 Share Posted March 5, 2005 Josh--a while back (Nov. 03) you mentioned the benefits of replacing your 3-wire O2 sensor with a 4-wire grounded one. I like that idea. I have a '95 Legacy L N/A, 5MT. Do you recall what the model # was for the generic 4-wire from oxygensensors.com? Thanx! Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted March 6, 2005 Share Posted March 6, 2005 I thought I had an email with the part #, but I can't find it. Email oxygensensors.com and just ask them. They should be able to help you out. Quote Link to comment Share on other sites More sharing options...
Handtool Posted March 23, 2005 Share Posted March 23, 2005 The part number for a universal 4 wire 02 sensor is 250-24000. This is made by Walker and costs $46.95 from oxygensensors.com. It's going in my '95 legacy tomorrow. Quote Link to comment Share on other sites More sharing options...
Handtool Posted March 23, 2005 Share Posted March 23, 2005 It's tomorrow. The new O2 sensor has made a huge difference in idle. Nice and smooth. Hopefully my MPG's will go back up as well. Quote Link to comment Share on other sites More sharing options...
Olnick Posted March 24, 2005 Share Posted March 24, 2005 Thanks for the information, Handtool. I'm ready to do the same thing if I can ever get my old sensor out! Did you solder the leads or use the crimp connectors that Walker provides? Where did you connect the ground? Quote Link to comment Share on other sites More sharing options...
Handtool Posted March 24, 2005 Share Posted March 24, 2005 Thanks for the information, Handtool. I'm ready to do the same thing if I can ever get my old sensor out! Did you solder the leads or use the crimp connectors that Walker provides? Where did you connect the ground? I crimped and soldered the leads. There is a small hole in the center of the crimp connector to apply the solder through. I extended the ground about 3 feet, zip tied it to the wiring harness along the firewall over to the gound points on the strut tower. Mine didn't want to budge either when things were cold. After letting the engine get up to operating temp it broke loose with no problem. Good luck. Quote Link to comment Share on other sites More sharing options...
lmdew Posted March 25, 2005 Share Posted March 25, 2005 Get a 7/8" tubing wrench. It will not round off the hex and slips over the wires. Works great! Quote Link to comment Share on other sites More sharing options...
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