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How do I know a bad O2 sensor?

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Old 09-19-2007, 03:00 PM
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Car: 89 IROC convert.
Engine: tpi 305
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Axle/Gears: 3.42 10 bolt
How do I know a bad O2 sensor?

I was in the garage last night with the door open, trying to sort out my fast idle problem, and my eyes and lungs were burning because the car is running so fat.

I've replaced the IAC and TPS but the car still idles at 1500 and is running rich as ****.

Could a bad O2 sensor be the problem?

I messed with the O2 sensor when I put headers on the car a week ago when the problem started.

I'd expect lean if it were just a vacuum leak.

Thanks in advance.
Old 09-19-2007, 06:08 PM
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Re: How do I know a bad O2 sensor?

i would check to make sure that the wire hasnt melted through on the headers.

if its not, replace the o2 anyway... they cost not very much at all
Old 09-19-2007, 07:25 PM
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Re: How do I know a bad O2 sensor?

If you grounded the O2 wire to its base for even a second, it is bad.

Take the opportunity to upgrade to a 3 wire heated O2. It will play nice with your headers (Some headers don't let the o2 sensor heat up enough).
Old 09-19-2007, 09:41 PM
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Re: How do I know a bad O2 sensor?

Sounds like good advice. Do you think a bad O2 be responsible for my problems?
Old 09-20-2007, 10:24 AM
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Re: How do I know a bad O2 sensor?

Depends. The ECm will not use the o2 sensor input at all until it reaches about 160 degrees of coolant temperature. If yours is running reach even before it iw warm, i'd say the problem lies elsewhere.
Old 09-21-2007, 08:22 AM
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Re: How do I know a bad O2 sensor?

You should prob replace it anyway, they are like $6 and you should replace them every 6 months anyway. fyi, it is hell to remove it in my 87, don't know if GM put it in the same place in 89, just a warning.
Old 09-21-2007, 10:40 AM
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Re: How do I know a bad O2 sensor?

I will replace it. Where can I find instructions on istalling the heated job? I should have done this when I put the headers on last week.
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