bad oxygen sensor?
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From: North Carolina
bad oxygen sensor?
how can you test a o2 to actually tell if it is bad?
cause the problem i am having is:
according to my vafc at 25% - 35% or 40% car car doesn't pull, almost like it shuts off the fuel.
if i press then pedal on down to 50% or more it runs hard and great. it also works if i drop down to 20% or less throttle.
so does that sound like a bad o2?
it did throw a code 1 but if i turned the car off then back on the light goes away.(without reseting the ecu)
cause the problem i am having is:
according to my vafc at 25% - 35% or 40% car car doesn't pull, almost like it shuts off the fuel.
if i press then pedal on down to 50% or more it runs hard and great. it also works if i drop down to 20% or less throttle.
so does that sound like a bad o2?
it did throw a code 1 but if i turned the car off then back on the light goes away.(without reseting the ecu)
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Joined: May 2001
Posts: 10,753
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From: Where snow is, I am.
Re: bad oxygen sensor? (SprayinCX)
Take a digital multimeter and verify the WHT wire goes from the O2 sensor to the D14 pinout (if it's OBD1), I believe for OBD2 it's D11. Could be wrong.
Could be a bad o2 if you have not touched anything.
Could be a bad o2 if you have not touched anything.
Joined: Apr 2003
Posts: 319
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From: USA
Re: bad oxygen sensor? (SprayinCX)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SprayinCX »</TD></TR><TR><TD CLASS="quote">how can you test a o2 to actually tell if it is bad?
cause the problem i am having is:
according to my vafc at 25% - 35% or 40% car car doesn't pull, almost like it shuts off the fuel.
if i press then pedal on down to 50% or more it runs hard and great. it also works if i drop down to 20% or less throttle.
so does that sound like a bad o2?
it did throw a code 1 but if i turned the car off then back on the light goes away.(without reseting the ecu)</TD></TR></TABLE>.
the best way is by using a scope to meassure voltage and time scale. however, a voltmeter can be used too. with engine warmed and o2 on close loop rev the motor at 2000 rpm and monitor the voltage reading - it should switch from .2 to .8 quickly not slowly. if o2 reading stays at the rich side of the scale - .5 to .9 create a vaccuum leak to how quick the o2 is responding to the leak.
well if reading is on the lean side .1 - .6 richen up the mixture . this is the reason why it is the best to do this test with a scope.
cause the problem i am having is:
according to my vafc at 25% - 35% or 40% car car doesn't pull, almost like it shuts off the fuel.
if i press then pedal on down to 50% or more it runs hard and great. it also works if i drop down to 20% or less throttle.
so does that sound like a bad o2?
it did throw a code 1 but if i turned the car off then back on the light goes away.(without reseting the ecu)</TD></TR></TABLE>.
the best way is by using a scope to meassure voltage and time scale. however, a voltmeter can be used too. with engine warmed and o2 on close loop rev the motor at 2000 rpm and monitor the voltage reading - it should switch from .2 to .8 quickly not slowly. if o2 reading stays at the rich side of the scale - .5 to .9 create a vaccuum leak to how quick the o2 is responding to the leak.
well if reading is on the lean side .1 - .6 richen up the mixture . this is the reason why it is the best to do this test with a scope.
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Joined: Aug 2002
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From: Tacoma, wa, USA
Re: bad oxygen sensor? (HONDADNA)
anyone know what happens if there is no o2 plugged into the cat? (B18c1 OBD1 in a 95 hatch) i've been driving for a couple days without one and assuming my a/f is way off... 
Joined: Apr 2003
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From: USA
Re: bad oxygen sensor? (fu*kface95hatch)
are we taking about the second o2 that came with obd 2 vehicle's and pre obd 2's? anyway, if your talking about the second o2 - it only monitor cat performance and the ecu/pcm also uses to perform self test. But as far as fuel mixture, I believe the ecu/pcm does not modify it. however if the primary o2 is not connected, the ecu/pcm will go into open loop and most likely it will run richer then normal..
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Re: bad oxygen sensor? (fu*kface95hatch)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fu*kface95hatch »</TD></TR><TR><TD CLASS="quote">anyone know what happens if there is no o2 plugged into the cat? (B18c1 OBD1 in a 95 hatch) i've been driving for a couple days without one and assuming my a/f is way off... </TD></TR></TABLE>
I have no o2 in my 93 ex... it's obd 1 and it's the only o2 I have...
It runs FINE... NO loss in gas milage... not running rough at all....
I believe the only time it truely uses it to tune the fuel is under wot... and if your car is anything like every car I've driven it performs better just above wot...
It does fine at wot too... My only downside is an irritating yellow mil.
</TD></TR></TABLE>I have no o2 in my 93 ex... it's obd 1 and it's the only o2 I have...
It runs FINE... NO loss in gas milage... not running rough at all....
I believe the only time it truely uses it to tune the fuel is under wot... and if your car is anything like every car I've driven it performs better just above wot...
It does fine at wot too... My only downside is an irritating yellow mil.
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