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Discussion Starter · #1 ·
Hey, Ive searched these forums for awhile but have some questions. I just bought a 2000 S10 extreme with the auto 2.2:(. Ive been getting a CEL now ever since i got it. guy i got it from said he put a new o2 in but light still came on. een disconnecting the batt didnt work. I assumed he bullshitted me so i went out and bought another upstream o2 sensor and just put it in. i went for a drive and my scanner still says p0134 pending after 5 miles. clear the code and still comes back.

I noticed no major exhaust leaks and got under the truck while it was running and could not hear any leaks. It does however look like it has a small aftermarket cat welded in.

I also have a hard starting problem. If car sits for a long period of time, it sarts within a second. other times it takes about 5-8 seconds, and stumbles for a second when it fires up. runs fine while driving.... im assuming fuel related..

Can anyone help me out figureing what this all is? Sorry for all the questions, but id like to figure this out. im getting about 20-22 mpg/300miles to a tank!
 

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Discussion Starter · #2 ·
bump, can anyone shed some light on this? i tried doin voltage tests and at idle the sensor is putting out .8 volts so i know its working and unplugged it looks liek the ecu is putting out 1 volt when the sensors unplugged. from what ive read, it seems to be functioning ok. What else can cause me to get a p0134 (bank1 precat o2 no activity detected)? i get the p0134 and p0134 pending everytime i drive.
 

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you said your getting .8 . does it fluctuate between .1-.9 rapidly.it should but that aftermarket cat could somehow be the problem. i know it says pre cat but if you're getting 20-22 mpg and that's not to much hwy driving that's pretty normal.try unplugging the after cat sensor to see if you get that code.
 

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then you have a problem.o2 sensor has to fluctuate rapidly as the low number is sensing oxygen and larger is checking hydrocarbons as unburnt fuel so that it tells ecm what ratio it is.if yours is stuck guess what it's not reading'' stoic '' 14.7 afr.
 

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Discussion Starter · #6 · (Edited)
so basically what your saying is im running very rich? what would/could cause that? ive had (2) different o2 sensors that read the same...

on another note..
i was told my motor was swapped with an 02 motor. is it possible he may have swapped harnesses with an 02 also? right now i got a 1 wire o2, but there is a tan wire hanging above the tranny that has solder on the end but isnt connected to anything. I know the 02 s10s had a 2 wire o2 sensor which used the purple and tan wires to ecu. could that be my issue? since im currently using a 1 wire o2 with just the purple wire?

hope that made sense.....

im just going on this blind... i dont know how to identify if i have an 02 motor/harness/ecu.
 

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Discussion Starter · #8 ·
my o2's are both two wires and I have a 2000 ls. So maybe that tan wire is the problem.
thats what i thought it was. but my 2000 only showed for 1 wire o2 sensors, everywhere i went.

Since i was told my motor was swapped to a 2002, just confuses the hell out of me. 2002 says its only motors were the flexfuel 2.2. so if he put a flex fuel in mine and swappedmy 2.2 stuff onto it, and swapped harnesses with an 02, then i would have that wire for the o2 sensor, hes just using the purple wire for a 1 wre.

Hoep some of that made sense....
 

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Did the previous owner swap the engine? If so, did he have this problem from the get go? The flex fuel provisions I believe were mostly in the form of fuel system modifications. What kind of scanner are you using? Can you check fuel pressure? Run a pressure check and see what you are running and see if it is within spec. Also, are you using "universal" O2 sensors? I've heard a lot of people who have issues with the Universal units. My primary concern at this point would be if the previous owner had this issue from the first key turn with the new motor. Also, is it a full 02 engine? From throttle body to oil pan? Or did they just swap in a short block? Now that we know this is a swapped motor, that throws a lot more variants into the equation. Also, if you are getting an upstream O2 issue, I would be surprised if its a problem with the catalytic converter and or the down stream O2. The down stream O2 does nothing to alter or change the air/fuel mixture. It is to determine whether the Catalytic Converter is operating properly. Upstream O2 issues are going to be a problem with the sensor itself, the wiring there of, or the A/F mixture is off due to air/fuel/spark issues
 
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