Oxygen sensor

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martingmc86

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I have an 86 GMC Sierra that I just converted to EFI with an atomic MSD 2910 but I need to connect my O2 sensor. I need help splicing in the new provided oxygen center to my original wire coming from the computer. Seems like it’s running pretty bad the check engine light came on throwing a code for oxygen sensor So my idea was connecting my original wire to the new oxygen sensor, but the new oxygen sensor has five wires need help identifying which one to splice in please help
 

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Sounds like your new sensor is a heated O2 sensor. Makes it much less sensitive to where its located in the exhaust pipe, since it does not rely on engine/exhaust heat to warm up.

I assume the original O2 sensor was a simple 2 wire, with no heat. I don’t know how you make the conversion, but my guess is that two of the extra wires on the new sensor will be ground and ignition-switched 12 volts.

This article might be of some help in understanding how to wire it.
 

martingmc86

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Sounds like your new sensor is a heated O2 sensor. Makes it much less sensitive to where its located in the exhaust pipe, since it does not rely on engine/exhaust heat to warm up.

I assume the original O2 sensor was a simple 2 wire, with no heat. I don’t know how you make the conversion, but my guess is that two of the extra wires on the new sensor will be ground and ignition-switched 12 volts.

This article might be of some help in understanding how to wire it.
The old one used to be single wire only
 

Ricko1966

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I have an 86 GMC Sierra that I just converted to EFI with an atomic MSD 2910 but I need to connect my O2 sensor. I need help splicing in the new provided oxygen center to my original wire coming from the computer. Seems like it’s running pretty bad the check engine light came on throwing a code for oxygen sensor So my idea was connecting my original wire to the new oxygen sensor, but the new oxygen sensor has five wires need help identifying which one to splice in please help
It's nowhere near that simple as just picking which wire to splice. Go buy a new 1 wire oxygen sensor. Actually I'd clear the code,test my oxygen sensor,and then see if the code came back,if my O2 sensor tested good but I was still throwing an O2 code,I'd be looking for things that will cause the o2 sensor to read out if range. A bad plug wire or plug,a vacuum leak,an exhaust leak,in correct idle mixture,etc. IMHO more good O2 sensors get changed than bad ones.
 
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75gmck25

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I am confused about what you have. You mention an Atomic EFI conversion, but then you have an existing 1 wire O2 sensor (from what system?). Install and wire the new sensor based on the directions from Atomic EFI. Just run the new wires for the sensor that came in the installation kit.
 

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I am confused about what you have. You mention an Atomic EFI conversion, but then you have an existing 1 wire O2 sensor (from what system?). Install and wire the new sensor based on the directions from Atomic EFI. Just run the new wires for the sensor that came in the installation kit.
The whole thing confuses me also. The other day he was asking about tps wires on a ccc carbureator. Today he's trying to run a 5 wire o2 sensor in place of a 1 wire,on what ecm?why?,who knows?And I've never seen a 5 wire 02 sensor 1 wire,3 wire,4 wire but a 5 wire is a new one on me
 
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martingmc86

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I am confused about what you have. You mention an Atomic EFI conversion, but then you have an existing 1 wire O2 sensor (from what system?). Install and wire the new sensor based on the directions from Atomic EFI. Just run the new wires for the sensor that came in the installation kit.
yes I’m trying to connect the o2 sensor existing wire that was single wire to the new o2 sensor I have that goes to my atomic msd EFI I swapped to carb to EFI the only issue is that I have a check engine light for an O2 sensor most likely because my o2 sensor wire is not connect so I’m trying to see if anyone has experience on this issue
 

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yes I’m trying to connect the o2 sensor existing wire that was single wire to the new o2 sensor I have that goes to my atomic msd EFI I swapped to carb to EFI the only issue is that I have a check engine light for an O2 sensor most likely because my o2 sensor wire is not connect so I’m trying to see if anyone has experience on this issue
So you still have your original ECM but you are throwing a code for O2 because you are using different fuel management. Okay got it. The easiest option and a sure bet is weld another bung into the exhaust and run your OE oxygen sensor to control your O.E. ecm,which probably also controls timing and egr purge. I wouldn't want to tie the two systems together, If you insist on doing it with just the one O2 sensor. You will need to backprobe all the wires on the new O2 sensor to verify what is power,what is ground and what is actual o2 sensor voltage out. We can guess,maybe we could, if we knew the manufacturer and part number for the O2 sensor in question.
 
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or at least a picture…
 

martingmc86

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So you still have your original ECM but you are throwing a code for O2 because you are using different fuel management. Okay got it. The easiest option and a sure bet is weld another bung into the exhaust and run your OE oxygen sensor to control your O.E. ecm,which probably also controls timing and egr purge. I wouldn't want to tie the two systems together, If you insist on doing it with just the one O2 sensor. You will need to backprobe all the wires on the new O2 sensor to verify what is power,what is ground and what is actual o2 sensor voltage out. We can guess,maybe we could, if we knew the manufacturer and part number for the O2 sensor in question.
 

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Ricko1966

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Are your colors grey white black yellow red? If so There's a pretty good chance the black wire is your narrow band signal. I wouldn't chance tying the two computers to one o2 sensor. I'd run both O2 sensors. The reason I said there's a pretty good chance,instead saying lm sure,I couldn't find info on your part number O2 sensor, I'm sure it's rebranded made by someone else . The diaghram I found was a generic wide band diaghram ,that uses those colors. Good luck
 
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martingmc86

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Are your colors grey white black yellow red? If so There's a pretty good chance the black wire is your narrow band signal. I wouldn't chance tying the two computers to one o2 sensor. I'd run both O2 sensors. The reason zi said there's a pretty good chance,instead of being sure I couldn't find info on your part number O2 sensor, I'm sure it's rebranded made by someone else . The diaghram I found was a generic diaghram ,using those colors. Good luck
I’m just trying to keep 1 02 sensor reason is I don’t have a welder to weld another band on it also I can probe four wires on the new O2 sensor. Can someone let me know what I should be looking for on the DVMeter
 

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Ground your voltmeter probe the black wire with the engine running,your looking for a voltage between .1 and 1 volt .5 is just about stoich. Test this signal by creating a vacuum leak by pulling a hose, your meter should drop voltage until the computer compensates. Spray some carb cleaner in the air cleaner your voltage should climb briefly. So if you get the varying signal more than .1 less than 1.1 you found the signal wire. Now if this fries the atomic ecu( not saying it will,but) who's going to pay for that? Take it to an exhaust shop and have someone weld in a bung for your O.E. O2 sensor. Or don't, it's your car.
 

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