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Can't find o2 sensor wires for the life of me-UPDATE

 
Old 02-18-2005, 01:29 AM
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Benton
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Default Can't find o2 sensor wires for the life of me-UPDATE

Ok, so I bought this car assuming the oxygen sensor was bad, as the car bucked on part throttle around 2-3k RPM, but it wasn't apparent at full throttle. Some preconceived notions I had were:

1. My car has a 3 wire o2 sensor (1986 32v)
2. It has 2 o2 sensors (obviously, I was wrong)
3. It would be easy to replace it

I'm pretty skilled mechanically (although electronics aren't my forte), but I cannot figure out this situation. Here's the deal: I only found one sensor, which I guess is correct. I just thought there were two. No problem. The sensor on this car only has TWO wires! I haven't read anything about a two wire sensor. Maybe one wire burned off? The sensor is disconnected, with NO wires above the cats' heat shield. I can't find a grommet or connector that resembles anything related to the oxygen sensor in my passenger footwell. Here are some pictures. By looking at these, can anyone tell me what I'm missing? I need to get this sensor hooked up and run the car before I completely tear it apart. The last picture is looking above the cats at the two wires coming out of the current sensor. Thanks in advance!
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Last edited by Benton; 02-18-2005 at 02:12 PM.
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Old 02-18-2005, 01:51 AM
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Marc Schwager
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I would say it's time for a new sensor. The wire should go through the body near the lower left of the fuse panel. Look around there you will probably locate a rubber grommet. On my 80, it is a single big thick green wire. IIRC The advantage of the three wire is that it has an internal heating element which brings it up to temerature faster and therefore making the engine run more efficiently during warm up.
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Old 02-18-2005, 01:56 AM
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Benton
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I've got some universal 3 wire sensors sitting in my garage waiting to be hooked up... I know I need a new one. Is your grommet visible where my pictures are aimed? I think the only place I haven't checked is under the sound deadening I still haven't removed from behind the fuse panel. 86 32v has a 3 wire sensor, correct?
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Old 02-18-2005, 06:59 AM
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Mike LaBranche
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First picture, bottom left, underneath the sound deadening material. You'll have to pry it back a bit until you discover the wire hole. It's supposed to have a rubber grommet that the wires feed thru and seals the hole. I'm pretty sure all 928's are 3 wire O2, stock. Some P.O.'s have replaced with cheaper 2 wire versions. My 84 is wired as a single green wire with rubber insulated, single prong connector and 2 white wires in a connector as a pair. The later cars, I think may have them all in a single connector. You may have to splice your new sensor in rather than being able to simply plug it in depending on which sensor you bought. HTH.
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Old 02-18-2005, 09:16 AM
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Garth S
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The grommet is easy to find, as the guys have noted. If in doubt, remove the sheet metal screws holding the heat shield in place and lower the tin onto the CAT - it's there.
There is one step that may require lowering the CAT, and that is the sensor removal and clean-up of the threads for the new 3-wire one. Hope you are lucky and can avoid too much hassle.
The other thing that caught my eye - where is the harness/wiring on the fuse block for the sensor connection? Can't see the end you need, unless it's tucked under somewhere.
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Old 02-18-2005, 09:30 AM
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I just took this picture of it on my '82 which is up on jackstands right now.
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Old 02-18-2005, 11:07 AM
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Look under your fuse panel. The harness may be tucked in under there..........It is black with a round plug on the end of it......IIRC, it contains 3 wires, two white and one black......The black one is the signal wire.......

Usually the harness runs along the floor, at the base of the fuse panel......from right to laft as you look at the panel....I don't see any sign of it in your pictures, but the right sides of them are not real clear.........I would be very surprised if a PO went through the trouble of removing the harness......
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Old 02-18-2005, 11:21 AM
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SteveG
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Originally Posted by Mike LaBranche
First picture, bottom left, underneath the sound deadening material. You'll have to pry it back a bit until you discover the wire hole. It's supposed to have a rubber grommet that the wires feed thru and seals the hole. I'm pretty sure all 928's are 3 wire O2, stock. Some P.O.'s have replaced with cheaper 2 wire versions. My 84 is wired as a single green wire with rubber insulated, single prong connector and 2 white wires in a connector as a pair. The later cars, I think may have them all in a single connector. You may have to splice your new sensor in rather than being able to simply plug it in depending on which sensor you bought. HTH.
I think you will find the grommet farther back, low where center consol meets floor, mid calf position. IIRC found it there on my '85. The center consol carpeted panel prob has to come off.
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Old 02-18-2005, 12:03 PM
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Dang I just replaced the cats on Meteor last night ... sorry Dude, I could have taken you killer pics
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Old 02-18-2005, 02:15 PM
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Ok, thanks guys. I can't believe I didn't think to look there... my shop manual makes it look like it is closer to the passenger seat. I have good news and bad news... the good is that I found the grommet with 3 holes in it for 3 wires. Bad news: There aren't any wires coming through the grommet! What should I do? I'm guessing I can locate where the oxygen sensor ultimately plugs into the computer, then run wires from that. Where is this? I don't see any stray plugs around the fusebox area, so I guess I'm stuck with finding the ending point then running all new wires. No big deal, I just have to find the location. Does anyone know this? I couldn't find anything in the shop manual after browsing for a few minutes. Thanks for the help.
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Old 02-18-2005, 02:24 PM
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As both Gretch & I said - there is no apparent harness! Loosen the fuse block fixtures and peek behind - finding the connector, or even loose ends here will be far easier than doing a primary rewire job. If not found, repost - and the wiring diags will be dug out ....
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Old 02-18-2005, 02:33 PM
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Make sure you disconnect the battery ground strap before you pull that fuse panel..............
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Old 02-18-2005, 02:39 PM
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Mark, On a side note, in the second pic it looks like the low octane loop is connected as well.( the two green wires) This would retard your timing somewhat. FWIW
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Old 02-18-2005, 02:43 PM
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Originally Posted by Garth S
As both Gretch & I said - there is no apparent harness! Loosen the fuse block fixtures and peek behind - finding the connector, or even loose ends here will be far easier than doing a primary rewire job. If not found, repost - and the wiring diags will be dug out ....
Yeah, sorry about that. I was caught up in finding it. I'll disconnect the battery and look all around for the harness and post back later today. Thanks
Originally Posted by Ed Taylor
Mark, On a side note, in the second pic it looks like the low octane loop is connected as well.( the two green wires) This would retard your timing somewhat. FWIW
Thanks for pointing that out, Ed. I will look at it closer. What do I do to undo it? Just disconnect?
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Old 02-18-2005, 02:52 PM
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Yep just disconnect. Wish they were all that easy. What part of metro Atl are you in?
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