How to get O2 wires to read correct OHM?
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Joined: Mar 2001
Posts: 3,445
From: Nashville, TN
How to get O2 wires to read correct OHM?
First let me start off by saying that I am a complete and utter cheap *** sometimes and I hate myself because of it.
This past winter I went and completly redone my motor. It is now a fully forged internals 355 with stage 1 ARE heads and a custom cam. In the process of installing the engine, I went and bought my longtubes. So needing O2 extensions is a must. Well, I forgot to order them, and when the time came to put the motor back, I didnt have any. So I cut the wiring harness, not the O2 wiring harness, and extended them. Since that time I have been working other bugs out of the entire buildup. Well, I have now offically gone thru 3 sets of O2's At first I thought it was the tune, dyno proved I was wrong. Next I thought it was the fuel pressure regulator because that went out. Again I was wrong, because last night I fouled another set. Right bank stuck at 4 and left bank being REALLY lazy, and threw a SES code. So basically what I am thinking is the wiring Ohms are off, and it is frying my O2's, which in turn cause the motor to run rich. I have two choices as far as I can tell. Buy a new wiring harness, which I can do, but that is a nice dent in my mod money. Or I can repair this one, but I dont know what the Ohms should read, and I am not entirely sure of how to fix them, or what to use to fix them. I have heard they are stainless steel lines, if so, solder wouldnt work real well. Neither would copper wire. So anyone have any ideas.???? Damn thing is sitting in my garage taunting me as it has all summer long. I'm about ready to light it on fire and roast marshmellows.
Q
This past winter I went and completly redone my motor. It is now a fully forged internals 355 with stage 1 ARE heads and a custom cam. In the process of installing the engine, I went and bought my longtubes. So needing O2 extensions is a must. Well, I forgot to order them, and when the time came to put the motor back, I didnt have any. So I cut the wiring harness, not the O2 wiring harness, and extended them. Since that time I have been working other bugs out of the entire buildup. Well, I have now offically gone thru 3 sets of O2's At first I thought it was the tune, dyno proved I was wrong. Next I thought it was the fuel pressure regulator because that went out. Again I was wrong, because last night I fouled another set. Right bank stuck at 4 and left bank being REALLY lazy, and threw a SES code. So basically what I am thinking is the wiring Ohms are off, and it is frying my O2's, which in turn cause the motor to run rich. I have two choices as far as I can tell. Buy a new wiring harness, which I can do, but that is a nice dent in my mod money. Or I can repair this one, but I dont know what the Ohms should read, and I am not entirely sure of how to fix them, or what to use to fix them. I have heard they are stainless steel lines, if so, solder wouldnt work real well. Neither would copper wire. So anyone have any ideas.???? Damn thing is sitting in my garage taunting me as it has all summer long. I'm about ready to light it on fire and roast marshmellows.
Q
Last edited by dreamer1q; Sep 3, 2003 at 07:43 PM.
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Joined: Jul 2003
Posts: 1,103
From: Hawaii
but I dont know what the Ohms should read
This one sentence alone can be the reason you are wasting oxygen sensors left and right.
Let me start by saying I am not expert in oxygen sensors but I could swear to you I read somewhere that the signal from the oxygen sensors is soooooo smal and that they are sooooo very delicate that is NOT advisable to attempt to read them using
a voltmeter unless its internal resistance was in the megaohms..
IF you have attempted to read the oxygen sensors output with your meter.... chances are you damaged them right there.
as for the conections.. and wiring... the lower the resistance the better.. the wires are the signal carriers and you do not want any signal loss while transfering the signal to the PCM.
I suggest you do a search on any manufacturers website or to contact Injuneer at this website... he may know wheather you have blown oxygen sensors due to the voltage/low impedance load you may have applied to the sensors delicate output.
I use a DMM short for Digital Multi-meter that has an imput impedance of 40 meg ohms and I still do not dare to apply the voltage to the sensor terminals.... Did you know that the meters apply a small voltage to the meter leads to read resistance???
That may be your culprit right there...
Marvin
Last edited by MentalCaseOne; Sep 3, 2003 at 07:41 PM.
Thread Starter
Registered User
Joined: Mar 2001
Posts: 3,445
From: Nashville, TN
Originally posted by MentalCaseOne
This one sentence alone can be the reason you are wasting oxygen sensors left and right.
Let me start by saying I am not expert in oxygen sensors but I could swear to you I read somewhere that the signal from the oxygen sensors is soooooo smal and that they are sooooo very delicate that is NOT advisable to attempt to read them using
a voltmeter unless its internal resistance was in the megaohms..
IF you have attempted to read the oxygen sensors output with your meter.... chances are you damaged them right there.
as for the conections.. and wiring... the lower the resistance the better.. the wires are the signal carriers and you do not want any signal loss while transfering the signal to the PCM.
I suggest you do a search on any manufacturers website or to contact Injuneer at this website... he may know wheather you have blown oxygen sensors due to the voltage/low impedance load you may have applied to the sensors delicate output.
I use a DMM short for Digital Multi-meter that has an imput impedance of 40 meg ohms and I still do not dare to apply the voltage to the sensor terminals.... Did you know that the meters apply a small voltage to the meter leads to read resistance???
That may be your culprit right there...
Marvin
This one sentence alone can be the reason you are wasting oxygen sensors left and right.
Let me start by saying I am not expert in oxygen sensors but I could swear to you I read somewhere that the signal from the oxygen sensors is soooooo smal and that they are sooooo very delicate that is NOT advisable to attempt to read them using
a voltmeter unless its internal resistance was in the megaohms..
IF you have attempted to read the oxygen sensors output with your meter.... chances are you damaged them right there.
as for the conections.. and wiring... the lower the resistance the better.. the wires are the signal carriers and you do not want any signal loss while transfering the signal to the PCM.
I suggest you do a search on any manufacturers website or to contact Injuneer at this website... he may know wheather you have blown oxygen sensors due to the voltage/low impedance load you may have applied to the sensors delicate output.
I use a DMM short for Digital Multi-meter that has an imput impedance of 40 meg ohms and I still do not dare to apply the voltage to the sensor terminals.... Did you know that the meters apply a small voltage to the meter leads to read resistance???
That may be your culprit right there...
Marvin
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