O2 sensor problem.
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Joined: Nov 2001
Posts: 3,515
From: Kansas
O2 sensor problem.
ive had a few strange oxygen sensor malfunctions lately and this one really has me scratching my head.
when i first start up my car, i know the O2s should read 450ish but for some reason one of mine reads 999 cold!? it still works when the car goes into closed loop however and looks to be pretty normal. so should i shell out $35 for a new sensor or just ignore this b/c it still works? the sensor isnt even a year old btw. i can tell you its not always been like this. in fact, i switched them from side to side after one of my O2s began to stick and only fluctuate from 200-500mV.. its not quite a year old either. i have lost a total of 3 sensors on that side after they all did this same thing and now that previously fine working O2 is reading 999 mV in open loop after putting it over on the right side. i know i dont have any burnt wiring harness.. though the plastic sleeve did get a little melted once when it got too close the collectors. do you guys think a the wiring harness is suffering being too close to the headers?? im gonna go out and look for some exposed wires now. thanks for looking
when i first start up my car, i know the O2s should read 450ish but for some reason one of mine reads 999 cold!? it still works when the car goes into closed loop however and looks to be pretty normal. so should i shell out $35 for a new sensor or just ignore this b/c it still works? the sensor isnt even a year old btw. i can tell you its not always been like this. in fact, i switched them from side to side after one of my O2s began to stick and only fluctuate from 200-500mV.. its not quite a year old either. i have lost a total of 3 sensors on that side after they all did this same thing and now that previously fine working O2 is reading 999 mV in open loop after putting it over on the right side. i know i dont have any burnt wiring harness.. though the plastic sleeve did get a little melted once when it got too close the collectors. do you guys think a the wiring harness is suffering being too close to the headers?? im gonna go out and look for some exposed wires now. thanks for looking
Thread Starter
Registered User
Joined: Nov 2001
Posts: 3,515
From: Kansas
i just checked and it is a sensor malfuntion.. not a problem with the harness. i plugged the other sensor into the harness on the side it was reading 999 and that sensor put out a reading of 449mV.
Registered User
Joined: Nov 2002
Posts: 143
From: Greenbrier, TN
turbo_z,
did you ever figure out anything?? I am kind of haivng the same problem but both of my o2s after a while start getting slow and only reading 290mv-490 mv.
And watching datamaster you can see the left o2 going from ready to not ready. When I swap them the worse of the two about scanning the mv(the left one) still scans bad on the right side, but the left o2 goes from ready to not ready no matter which o2 I have in there. But when they are new, they never went from ready to not ready. They ran good. Just when they start to act up will the left one switch from ready to not ready.
Just wondering if you ever figured anything out? What kind of headers do you have? Do you have a cat still in the exhaust.
I think I will ask for a case of new o2 sensors for christmas if I cant figure it out. They tend to last about 1.5 months
Jason
did you ever figure out anything?? I am kind of haivng the same problem but both of my o2s after a while start getting slow and only reading 290mv-490 mv.
And watching datamaster you can see the left o2 going from ready to not ready. When I swap them the worse of the two about scanning the mv(the left one) still scans bad on the right side, but the left o2 goes from ready to not ready no matter which o2 I have in there. But when they are new, they never went from ready to not ready. They ran good. Just when they start to act up will the left one switch from ready to not ready.
Just wondering if you ever figured anything out? What kind of headers do you have? Do you have a cat still in the exhaust.
I think I will ask for a case of new o2 sensors for christmas if I cant figure it out. They tend to last about 1.5 months
Jason
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