o2 sensor problems
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From: Wilmington, NC, United States
o2 sensor problems
I currently had a check engine light come on reading that my primary o2 sensor was bad....the cars has slowed down quite a bit.....I put a new o2 sensor in....reset the ecu, and the code threw again.....i have tried to clear the code over and over again, and i am having no luck at all.....if someone could give me a bit of advice that would be useful in resolving this problem please lmk....
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Re: o2 sensor problems (allmotorsi04)
If you have voltmeter try checking your o2 input voltage at idle - should be switching from .2-.8 volts quickly. However, check your fuel filter for cloggage.
(pour the fuel from the filter into clean container - if it look brown the partials falls out replace it)
(pour the fuel from the filter into clean container - if it look brown the partials falls out replace it)
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Re: o2 sensor problems (allmotorsi04)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allmotorsi04 »</TD></TR><TR><TD CLASS="quote">I currently had a check engine light come on reading that my primary o2 sensor was bad....
</TD></TR></TABLE>
What code?
</TD></TR></TABLE>
What code?
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Re: o2 sensor problems (allmotorsi04)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allmotorsi04 »</TD></TR><TR><TD CLASS="quote">I currently had a check engine light come on reading that my primary o2 sensor was bad....the cars has slowed down quite a bit.....I put a new o2 sensor in....reset the ecu, and the code threw again.....i have tried to clear the code over and over again, and i am having no luck at all.....if someone could give me a bit of advice that would be useful in resolving this problem please lmk....
</TD></TR></TABLE>
**** im having the same problems with my 99 si...its a pain in the ***, ive bought 3 new o2's thinkin i bought all bad o2 sensors, but it has to be something in the wiring. this is scaring me, i had a pro honda mechanic look at it today and he cant even figure it out. he tested the ecu, sensor, and grounding, and i guess he came up with sumthing about grounding...he told me hes gonna make a new grounding wire or sum ****, but it doesnt sound pretty. this is really pissing me off....motors runnin so rich i had to bump my timing down. also, im sposed to get my head built this weekend, and dynotuned, now i dont think i can cuz of this problem...PLEASE HELP!!!
</TD></TR></TABLE>
**** im having the same problems with my 99 si...its a pain in the ***, ive bought 3 new o2's thinkin i bought all bad o2 sensors, but it has to be something in the wiring. this is scaring me, i had a pro honda mechanic look at it today and he cant even figure it out. he tested the ecu, sensor, and grounding, and i guess he came up with sumthing about grounding...he told me hes gonna make a new grounding wire or sum ****, but it doesnt sound pretty. this is really pissing me off....motors runnin so rich i had to bump my timing down. also, im sposed to get my head built this weekend, and dynotuned, now i dont think i can cuz of this problem...PLEASE HELP!!!
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Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">If you have voltmeter try checking your o2 input voltage at idle - should be switching from .2-.8 volts quickly. However, check your fuel filter for cloggage.
(pour the fuel from the filter into clean container - if it look brown the partials falls out replace it)</TD></TR></TABLE>
how does that have anything to do with o2 sensor problems, also i know it has nothing to do with it, i just replaced mine and im having the exact same problem with my Si
(pour the fuel from the filter into clean container - if it look brown the partials falls out replace it)</TD></TR></TABLE>
how does that have anything to do with o2 sensor problems, also i know it has nothing to do with it, i just replaced mine and im having the exact same problem with my Si
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Re: o2 sensor problems (CleenSi)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CleenSi »</TD></TR><TR><TD CLASS="quote">
how does that have anything to do with o2 sensor problems, also i know it has nothing to do with it, i just replaced mine and im having the exact same problem with my Si</TD></TR></TABLE>
Maybe your problem lies elswhere? Checking the sensors for proper operation can save alot of time and money. What code is yours putting out?
how does that have anything to do with o2 sensor problems, also i know it has nothing to do with it, i just replaced mine and im having the exact same problem with my Si</TD></TR></TABLE>
Maybe your problem lies elswhere? Checking the sensors for proper operation can save alot of time and money. What code is yours putting out?
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From: USA
Re: o2 sensor problems (CleenSi)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CleenSi »</TD></TR><TR><TD CLASS="quote">
how does that have anything to do with o2 sensor problems, also i know it has nothing to do with it, i just replaced mine and im having the exact same problem with my Si</TD></TR></TABLE>
Well if the fuel filter is clogged the o2 sensor will sense a lean condition and set a code. Also, if the air filter is clogged and not allowing enough air to the engine it will set a o2 code.
The reseason for a volt meter is to check o2 operation. if the reading is anywhere from .2 - .6 it's in the lean side or if reading is .5-.9 it's in the rich side.
A voltmeter or engine lab scope can tell if you the o2 sensor in operating correctly. for example, If my o2 sensor reading is between .5-.9 - at 2000 rpm I will creat a vaccuum leak. I will plug and unplug the vaccuum leak to see if the o2 is respounding. Now, if its in the leanside I will induce propane to see how well the o2 respound to the rich mixture. An o2 sensor should be able to respound to fuel changes within 1miliseconds form rich to lean and back to rich. That's way it great to have an engine scope - you get voltage and time scale. For me, I use the OTC version engine scope which also do ignition KV, burn time, and burn slopes.
Now, I hope you understand what I was trying to say
how does that have anything to do with o2 sensor problems, also i know it has nothing to do with it, i just replaced mine and im having the exact same problem with my Si</TD></TR></TABLE>
Well if the fuel filter is clogged the o2 sensor will sense a lean condition and set a code. Also, if the air filter is clogged and not allowing enough air to the engine it will set a o2 code.
The reseason for a volt meter is to check o2 operation. if the reading is anywhere from .2 - .6 it's in the lean side or if reading is .5-.9 it's in the rich side.
A voltmeter or engine lab scope can tell if you the o2 sensor in operating correctly. for example, If my o2 sensor reading is between .5-.9 - at 2000 rpm I will creat a vaccuum leak. I will plug and unplug the vaccuum leak to see if the o2 is respounding. Now, if its in the leanside I will induce propane to see how well the o2 respound to the rich mixture. An o2 sensor should be able to respound to fuel changes within 1miliseconds form rich to lean and back to rich. That's way it great to have an engine scope - you get voltage and time scale. For me, I use the OTC version engine scope which also do ignition KV, burn time, and burn slopes.
Now, I hope you understand what I was trying to say
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Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
Well if the fuel filter is clogged the o2 sensor will sense a lean condition and set a code. Also, if the air filter is clogged and not allowing enough air to the engine it will set a o2 code.
The reseason for a volt meter is to check o2 operation. if the reading is anywhere from .2 - .6 it's in the lean side or if reading is .5-.9 it's in the rich side.
A voltmeter or engine lab scope can tell if you the o2 sensor in operating correctly. for example, If my o2 sensor reading is between .5-.9 - at 2000 rpm I will creat a vaccuum leak. I will plug and unplug the vaccuum leak to see if the o2 is respounding. Now, if its in the leanside I will induce propane to see how well the o2 respound to the rich mixture. An o2 sensor should be able to respound to fuel changes within 1miliseconds form rich to lean and back to rich. That's way it great to have an engine scope - you get voltage and time scale. For me, I use the OTC version engine scope which also do ignition KV, burn time, and burn slopes.
Now, I hope you understand what I was trying to say</TD></TR></TABLE>
cool, yea its runnin like .8 or sumthin...so what do i do now..?
-thanks.
Well if the fuel filter is clogged the o2 sensor will sense a lean condition and set a code. Also, if the air filter is clogged and not allowing enough air to the engine it will set a o2 code.
The reseason for a volt meter is to check o2 operation. if the reading is anywhere from .2 - .6 it's in the lean side or if reading is .5-.9 it's in the rich side.
A voltmeter or engine lab scope can tell if you the o2 sensor in operating correctly. for example, If my o2 sensor reading is between .5-.9 - at 2000 rpm I will creat a vaccuum leak. I will plug and unplug the vaccuum leak to see if the o2 is respounding. Now, if its in the leanside I will induce propane to see how well the o2 respound to the rich mixture. An o2 sensor should be able to respound to fuel changes within 1miliseconds form rich to lean and back to rich. That's way it great to have an engine scope - you get voltage and time scale. For me, I use the OTC version engine scope which also do ignition KV, burn time, and burn slopes.
Now, I hope you understand what I was trying to say</TD></TR></TABLE>
cool, yea its runnin like .8 or sumthin...so what do i do now..?
-thanks.
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From: USA
Re: o2 sensor problems (CleenSi)
Well if your getting .8 voltage of idle(2000RPM) your running rich. Now let's think - what factors can cause a rich condition:
1) dirty air filter
2) crank to cam timing
3) ingition timing (too retarded)
5) vacccuum leaks
6) valves to tight
7) High resistanc in secondary ingition(wires, spark plugs, rotor, or cap)
8) leaky injectors
9) compression
I would check this out first in orders eliminating possiblies. Also, remove your msd unit this may a factor in your problem as well.
1) dirty air filter
2) crank to cam timing
3) ingition timing (too retarded)
5) vacccuum leaks
6) valves to tight
7) High resistanc in secondary ingition(wires, spark plugs, rotor, or cap)
8) leaky injectors
9) compression
I would check this out first in orders eliminating possiblies. Also, remove your msd unit this may a factor in your problem as well.
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Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
5) vacccuum leaks
7) High resistanc in secondary ingition(wires, spark plugs, rotor, or cap)
9) compression
</TD></TR></TABLE>
Wouldn't these show up as a lean condition?
5) vacccuum leaks
7) High resistanc in secondary ingition(wires, spark plugs, rotor, or cap)
9) compression
</TD></TR></TABLE>
Wouldn't these show up as a lean condition?
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Re: o2 sensor problems (Chiovnidca)
5) Vaccum leaks
If it was an exhaust leak, before the primary O2, it would lead to a rich mixture as well, yeah?
7) High resistance in secondary ingition(wires, spark plugs, rotor, or cap)
Wouldn't this indicate a weak spark leading to a possible rich condition?
9) Compression
If the mix couldn't be compressed correctly, wouldn't we have a slower burn which might result in a richer mixture?
Perhaps my logic is flawed here, but with the above scenarios, how would a lean condition show up?
If it was an exhaust leak, before the primary O2, it would lead to a rich mixture as well, yeah?
7) High resistance in secondary ingition(wires, spark plugs, rotor, or cap)
Wouldn't this indicate a weak spark leading to a possible rich condition?
9) Compression
If the mix couldn't be compressed correctly, wouldn't we have a slower burn which might result in a richer mixture?
Perhaps my logic is flawed here, but with the above scenarios, how would a lean condition show up?
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Re: o2 sensor problems (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">
Wouldn't these show up as a lean condition?</TD></TR></TABLE>
No! if there is slight vaccuum leak where the map sensor is seeing a lower intake vaccuum. The PCM will richen up the mixture.
If the secondary system was low KV making unable to ignite the fuel mixture the o2 sensor will see as a rich condition in the exhaust stream. If you have a gas bench try creating a misfire in the and see what your CO reads and what the o2 sensor see's.
if the rings are week allowing excessive gas blow bys to enter the crank than normal. when the PCV introduce the blowby back in the intake it too can cause an o2 sensor read rich. I'm sure if you are emmission cert. or fix any emmission gas fail fialures. I have fix may failed emmission due to dirty crank cases - failing HC and higher than normal CO readings.
As a tech you should know this.
Wouldn't these show up as a lean condition?</TD></TR></TABLE>
No! if there is slight vaccuum leak where the map sensor is seeing a lower intake vaccuum. The PCM will richen up the mixture.
If the secondary system was low KV making unable to ignite the fuel mixture the o2 sensor will see as a rich condition in the exhaust stream. If you have a gas bench try creating a misfire in the and see what your CO reads and what the o2 sensor see's.
if the rings are week allowing excessive gas blow bys to enter the crank than normal. when the PCV introduce the blowby back in the intake it too can cause an o2 sensor read rich. I'm sure if you are emmission cert. or fix any emmission gas fail fialures. I have fix may failed emmission due to dirty crank cases - failing HC and higher than normal CO readings.
As a tech you should know this.
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From: USA
Re: o2 sensor problems (EE_Chris)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">5) Vaccum leaks
If it was an exhaust leak, before the primary O2, it would lead to a rich mixture as well, yeah?
7) High resistance in secondary ingition(wires, spark plugs, rotor, or cap)
Wouldn't this indicate a weak spark leading to a possible rich condition?
9) Compression
If the mix couldn't be compressed correctly, wouldn't we have a slower burn which might result in a richer mixture?
Perhaps my logic is flawed here, but with the above scenarios, how would a lean condition show up?</TD></TR></TABLE>
Yes! if there is an exhaust before the primary o2 sensor the o2 would see it as a lean condition.
And on the other two - your are correct
If it was an exhaust leak, before the primary O2, it would lead to a rich mixture as well, yeah?
7) High resistance in secondary ingition(wires, spark plugs, rotor, or cap)
Wouldn't this indicate a weak spark leading to a possible rich condition?
9) Compression
If the mix couldn't be compressed correctly, wouldn't we have a slower burn which might result in a richer mixture?
Perhaps my logic is flawed here, but with the above scenarios, how would a lean condition show up?</TD></TR></TABLE>
Yes! if there is an exhaust before the primary o2 sensor the o2 would see it as a lean condition.
And on the other two - your are correct
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Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">If the secondary system was low KV making unable to ignite the fuel mixture the o2 sensor will see as a rich condition in the exhaust stream. If you have a gas bench try creating a misfire in the and see what your CO reads and what the o2 sensor see's.</TD></TR></TABLE>How would that work?
With a consistant misfire, the O2 sensor doesn't measure the unburned fuel, it measures the 'unused' oxygen. So with all that excess O2 it would think its lean, right?
With a consistant misfire, the O2 sensor doesn't measure the unburned fuel, it measures the 'unused' oxygen. So with all that excess O2 it would think its lean, right?
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From: USA
Re: o2 sensor problems (JimBlake)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake »</TD></TR><TR><TD CLASS="quote">How would that work?
With a consistant misfire, the O2 sensor doesn't measure the unburned fuel, it measures the 'unused' oxygen. So with all that excess O2 it would think its lean, right?
</TD></TR></TABLE>
Remember o2 sensor does not care how unburn fuel is present it only cares how may oxgyen partials are present.
Well to answer your question it' yes and no. Any reading above .5 is consider a rich and anything under .4 is consided lean. Well if you have just one cylinder with a misfire depending on how bad and if it is lean misfire on all cylinders. So of course if you have misfire the o2 may read a lean condition. But on the note, if you just have one cylinder that has lean misfire than the o2 may or maynot read a lean nor rich condition. But when I stated secondary ignition misfire, if you all of proper fuel and oxygen but a bad or weak spark this on four cylinder or perhaps two. The o2 sensor voltage may switch from .5 to .8 telling the ECM the mixture is rich.
With a consistant misfire, the O2 sensor doesn't measure the unburned fuel, it measures the 'unused' oxygen. So with all that excess O2 it would think its lean, right?
</TD></TR></TABLE>
Remember o2 sensor does not care how unburn fuel is present it only cares how may oxgyen partials are present.
Well to answer your question it' yes and no. Any reading above .5 is consider a rich and anything under .4 is consided lean. Well if you have just one cylinder with a misfire depending on how bad and if it is lean misfire on all cylinders. So of course if you have misfire the o2 may read a lean condition. But on the note, if you just have one cylinder that has lean misfire than the o2 may or maynot read a lean nor rich condition. But when I stated secondary ignition misfire, if you all of proper fuel and oxygen but a bad or weak spark this on four cylinder or perhaps two. The o2 sensor voltage may switch from .5 to .8 telling the ECM the mixture is rich.
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From: Cincinnati,, Oh
Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
No! if there is slight vaccuum leak where the map sensor is seeing a lower intake vaccuum. The PCM will richen up the mixture.
</TD></TR></TABLE>
The MAP sees a slightly vacuum so it richens it up some. So your letting in a little extra air, the ECU is giving it a little extra fuel. so what happens? It is only going to raise the idle speed up a bit, and it is going to go on as if the throttle were open a little. Once the leak gets larger, such as a stuck open IAC valve, it can't cope. The idle starts bouncing up and down, that's lean. If you get an even larger vacuum leak, like a bad intake manifold gasket, then it starts missfireing. Then it show really lean.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
If the secondary system was low KV making unable to ignite the fuel mixture the o2 sensor will see as a rich condition in the exhaust stream. </TD></TR></TABLE>
You have that backwards. If the fuel mixture doesn't burn, the o2 sensor is going to show a lean condition because of the extra oxygen. Remember, the only thing an o2 sensor looks for oxygen (duh) it doesn't matter how much fuel is mixed in with it, it just sees the o2. High oxygen = lean.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
if the rings are week allowing excessive gas blow bys to enter the crank than normal. when the PCV introduce the blowby back in the intake it too can cause an o2 sensor read rich. I'm sure if you are emmission cert. or fix any emmission gas fail fialures. I have fix may failed emmission due to dirty crank cases - failing HC and higher than normal CO readings.
</TD></TR></TABLE>
I'm not going to argue with that. But you had compression listed. Compression itself isn't going to cause a problem until it gets so low it starts misfiring, then there goes the o2 again.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
As a tech you should know this.</TD></TR></TABLE>
LOL,you are still a lube tech, right?
No! if there is slight vaccuum leak where the map sensor is seeing a lower intake vaccuum. The PCM will richen up the mixture.
</TD></TR></TABLE>
The MAP sees a slightly vacuum so it richens it up some. So your letting in a little extra air, the ECU is giving it a little extra fuel. so what happens? It is only going to raise the idle speed up a bit, and it is going to go on as if the throttle were open a little. Once the leak gets larger, such as a stuck open IAC valve, it can't cope. The idle starts bouncing up and down, that's lean. If you get an even larger vacuum leak, like a bad intake manifold gasket, then it starts missfireing. Then it show really lean.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
If the secondary system was low KV making unable to ignite the fuel mixture the o2 sensor will see as a rich condition in the exhaust stream. </TD></TR></TABLE>
You have that backwards. If the fuel mixture doesn't burn, the o2 sensor is going to show a lean condition because of the extra oxygen. Remember, the only thing an o2 sensor looks for oxygen (duh) it doesn't matter how much fuel is mixed in with it, it just sees the o2. High oxygen = lean.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
if the rings are week allowing excessive gas blow bys to enter the crank than normal. when the PCV introduce the blowby back in the intake it too can cause an o2 sensor read rich. I'm sure if you are emmission cert. or fix any emmission gas fail fialures. I have fix may failed emmission due to dirty crank cases - failing HC and higher than normal CO readings.
</TD></TR></TABLE>
I'm not going to argue with that. But you had compression listed. Compression itself isn't going to cause a problem until it gets so low it starts misfiring, then there goes the o2 again.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
As a tech you should know this.</TD></TR></TABLE>
LOL,you are still a lube tech, right?
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Joined: Apr 2002
Posts: 7,574
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From: Cincinnati,, Oh
Re: o2 sensor problems (EE_Chris)
Hey, I havn't seen you here much lately. Been alright?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">5) Vaccum leaks
If it was an exhaust leak, before the primary O2, it would lead to a rich mixture as well, yeah?
</TD></TR></TABLE>
If it had an exhaust leak before the o2, that same hole in the exhaust will also let in outside air. (Beleive it or not.) That would make it show a lean condition.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">5) Vaccum leaks
7) High resistance in secondary ingition(wires, spark plugs, rotor, or cap)
Wouldn't this indicate a weak spark leading to a possible rich condition?
</TD></TR></TABLE>
A weak spark usually results in a misfire. Again a high o2 level.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">
9) Compression
If the mix couldn't be compressed correctly, wouldn't we have a slower burn which might result in a richer mixture?
</TD></TR></TABLE>
That would cause either a misfire or an incomplete burn. Guess what, more oxygen going to the o2 sensor.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">5) Vaccum leaks
If it was an exhaust leak, before the primary O2, it would lead to a rich mixture as well, yeah?
</TD></TR></TABLE>
If it had an exhaust leak before the o2, that same hole in the exhaust will also let in outside air. (Beleive it or not.) That would make it show a lean condition.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">5) Vaccum leaks
7) High resistance in secondary ingition(wires, spark plugs, rotor, or cap)
Wouldn't this indicate a weak spark leading to a possible rich condition?
</TD></TR></TABLE>
A weak spark usually results in a misfire. Again a high o2 level.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">
9) Compression
If the mix couldn't be compressed correctly, wouldn't we have a slower burn which might result in a richer mixture?
</TD></TR></TABLE>
That would cause either a misfire or an incomplete burn. Guess what, more oxygen going to the o2 sensor.
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From: USA
Re: o2 sensor problems (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">
The MAP sees a slightly vacuum so it richens it up some. So your letting in a little extra air, the ECU is giving it a little extra fuel. so what happens? It is only going to raise the idle speed up a bit, and it is going to go on as if the throttle were open a little. Once the leak gets larger, such as a stuck open IAC valve, it can't cope. The idle starts bouncing up and down, that's lean. If you get an even larger vacuum leak, like a bad intake manifold gasket, then it starts missfireing. Then it show really lean.
You have that backwards. If the fuel mixture doesn't burn, the o2 sensor is going to show a lean condition because of the extra oxygen. Remember, the only thing an o2 sensor looks for oxygen (duh) it doesn't matter how much fuel is mixed in with it, it just sees the o2. High oxygen = lean.
I'm not going to argue with that. But you had compression listed. Compression itself isn't going to cause a problem until it gets so low it starts misfiring, then there goes the o2 again.
LOL,you are still a lube tech, right?</TD></TR></TABLE>
ASE master, L1, Honda gold level tech, and Phase2 cert. Dam I much one good as tech lube
.
Any aways, A slight vaccuum leak will cuase a rich condition. A good exampe would be a Passport - creat a vaccuum leak and wach the shortrim and longtrim go high as 20% and cause a misfire.
I guess your just Honda smart which is okay. however, also take the Honda accord plug the PGM tester in and remove a small vaccuum line hose and watch the injector on time, fuel trims, and o2. A rich condition will occur.
Another example, Acura vigor hotwire system - a vaccuum leak will cause a rich condition as well.
Mazda's are know cause o2 sensor codes for rich condition due to dirty hot wires and vaccuum leaks at the intake manifolds. See for me, I just don't work on Honda's.
2 years with Nissan, 3 years with Acura, 2 years with Honda, 1 independs repair shop. pretty good back for a lube tech that make 22.90 flate rate right not to mention that I'm ASE master, Gold level Honda Tech, ASE L1, and phase2 emmission cert.
The MAP sees a slightly vacuum so it richens it up some. So your letting in a little extra air, the ECU is giving it a little extra fuel. so what happens? It is only going to raise the idle speed up a bit, and it is going to go on as if the throttle were open a little. Once the leak gets larger, such as a stuck open IAC valve, it can't cope. The idle starts bouncing up and down, that's lean. If you get an even larger vacuum leak, like a bad intake manifold gasket, then it starts missfireing. Then it show really lean.
You have that backwards. If the fuel mixture doesn't burn, the o2 sensor is going to show a lean condition because of the extra oxygen. Remember, the only thing an o2 sensor looks for oxygen (duh) it doesn't matter how much fuel is mixed in with it, it just sees the o2. High oxygen = lean.
I'm not going to argue with that. But you had compression listed. Compression itself isn't going to cause a problem until it gets so low it starts misfiring, then there goes the o2 again.
LOL,you are still a lube tech, right?
</TD></TR></TABLE>ASE master, L1, Honda gold level tech, and Phase2 cert. Dam I much one good as tech lube
.Any aways, A slight vaccuum leak will cuase a rich condition. A good exampe would be a Passport - creat a vaccuum leak and wach the shortrim and longtrim go high as 20% and cause a misfire.
I guess your just Honda smart which is okay. however, also take the Honda accord plug the PGM tester in and remove a small vaccuum line hose and watch the injector on time, fuel trims, and o2. A rich condition will occur.
Another example, Acura vigor hotwire system - a vaccuum leak will cause a rich condition as well.
Mazda's are know cause o2 sensor codes for rich condition due to dirty hot wires and vaccuum leaks at the intake manifolds. See for me, I just don't work on Honda's.
2 years with Nissan, 3 years with Acura, 2 years with Honda, 1 independs repair shop. pretty good back for a lube tech that make 22.90 flate rate right not to mention that I'm ASE master, Gold level Honda Tech, ASE L1, and phase2 emmission cert.
Honda-Tech Member
Joined: Apr 2002
Posts: 7,574
Likes: 6
From: Cincinnati,, Oh
Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
Any aways, A slight vaccuum leak will cuase a rich condition. A good exampe would be a Passport - creat a vaccuum leak and wach the shortrim and longtrim go high as 20% and cause a misfire.
</TD></TR></TABLE>
Don't you know we're supposed to hate Passports. (Damn Izusus) One reason is because they use a MAF sensor, which are easily affected by vacuum leaks. Same with the Vigor and Mazda right?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
2 years with Nissan, 3 years with Acura, 2 years with Honda, 1 independs repair shop. pretty good back for a lube tech that make 22.90 flate rate right not to mention that I'm ASE master, Gold level Honda Tech, ASE L1, and phase2 emmission cert. </TD></TR></TABLE>
I was starting to get scared, then you said you were only a gold level. Next year you'll get platinum.
Any aways, A slight vaccuum leak will cuase a rich condition. A good exampe would be a Passport - creat a vaccuum leak and wach the shortrim and longtrim go high as 20% and cause a misfire.
</TD></TR></TABLE>
Don't you know we're supposed to hate Passports. (Damn Izusus) One reason is because they use a MAF sensor, which are easily affected by vacuum leaks. Same with the Vigor and Mazda right?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">
2 years with Nissan, 3 years with Acura, 2 years with Honda, 1 independs repair shop. pretty good back for a lube tech that make 22.90 flate rate right not to mention that I'm ASE master, Gold level Honda Tech, ASE L1, and phase2 emmission cert. </TD></TR></TABLE>
I was starting to get scared, then you said you were only a gold level.
Next year you'll get platinum.
Honda-Tech Member
Joined: Oct 2001
Posts: 4,611
Likes: 3
From: Severn, MD
Re: o2 sensor problems (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">If it had an exhaust leak before the o2, that same hole in the exhaust will also let in outside air. (Beleive it or not.) That would make it show a lean condition.
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Agreed that it would lead to a lean O2 reading, but wouldn't that still "lead to a rich mixture" - ST and LTFT go up, right?
I follow your logic on misfiring and its effects on the O2 - thanks for shedding light.
</TD></TR></TABLE>
Agreed that it would lead to a lean O2 reading, but wouldn't that still "lead to a rich mixture" - ST and LTFT go up, right?
I follow your logic on misfiring and its effects on the O2 - thanks for shedding light.
Joined: Apr 2003
Posts: 319
Likes: 0
From: USA
Re: o2 sensor problems (Chiovnidca)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca »</TD></TR><TR><TD CLASS="quote">
Don't you know we're supposed to hate Passports. (Damn Izusus) One reason is because they use a MAF sensor, which are easily affected by vacuum leaks. Same with the Vigor and Mazda right?
I was starting to get scared, then you said you were only a gold level. Next year you'll get platinum.</TD></TR></TABLE>
\
I love the passport. I lot of guy at my shop hate them. But the way I look at it more work for me. The passport is not bad at all. I think many Honda guys just don't like it because it's Hondas step child. A car is a car they suck, compress, ignite, and exhale.
I can't wait to recieve the platinum cert. from Honda. I get nice ring plus it time to as my service director manager for more money like $5.00 increase.
Don't you know we're supposed to hate Passports. (Damn Izusus) One reason is because they use a MAF sensor, which are easily affected by vacuum leaks. Same with the Vigor and Mazda right?
I was starting to get scared, then you said you were only a gold level.
Next year you'll get platinum.</TD></TR></TABLE>\
I love the passport. I lot of guy at my shop hate them. But the way I look at it more work for me. The passport is not bad at all. I think many Honda guys just don't like it because it's Hondas step child. A car is a car they suck, compress, ignite, and exhale.
I can't wait to recieve the platinum cert. from Honda. I get nice ring plus it time to as my service director manager for more money like $5.00 increase.
Honda-Tech Member
Joined: Apr 2002
Posts: 7,574
Likes: 6
From: Cincinnati,, Oh
Re: o2 sensor problems (EE_Chris)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris »</TD></TR><TR><TD CLASS="quote">
Agreed that it would lead to a lean O2 reading, but wouldn't that still "lead to a rich mixture" - ST and LTFT go up, right?
</TD></TR></TABLE>
Yea, the extra oxygen would cause the sensor to send a lean signal to the ECU, which would then richen up the mixture. You were right on this, I was just going on about the o2 sensor voltage.
Modified by Chiovnidca at 5:39 PM 12/2/2003
Agreed that it would lead to a lean O2 reading, but wouldn't that still "lead to a rich mixture" - ST and LTFT go up, right?
</TD></TR></TABLE>
Yea, the extra oxygen would cause the sensor to send a lean signal to the ECU, which would then richen up the mixture. You were right on this, I was just going on about the o2 sensor voltage.
Modified by Chiovnidca at 5:39 PM 12/2/2003
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Re: o2 sensor problems (HONDADNA)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HONDADNA »</TD></TR><TR><TD CLASS="quote">Well if your getting .8 voltage of idle(2000RPM) your running rich. Now let's think - what factors can cause a rich condition:
1) dirty air filter
2) crank to cam timing
3) ingition timing (too retarded)
5) vacccuum leaks
6) valves to tight
7) High resistanc in secondary ingition(wires, spark plugs, rotor, or cap)
8) leaky injectors
9) compression
I would check this out first in orders eliminating possiblies. Also, remove your msd unit this may a factor in your problem as well.
</TD></TR></TABLE>
dont have MSD, thank god!
1) dirty air filter
2) crank to cam timing
3) ingition timing (too retarded)
5) vacccuum leaks
6) valves to tight
7) High resistanc in secondary ingition(wires, spark plugs, rotor, or cap)
8) leaky injectors
9) compression
I would check this out first in orders eliminating possiblies. Also, remove your msd unit this may a factor in your problem as well.
</TD></TR></TABLE>
dont have MSD, thank god!
