My CEL is on so i went into auto zone, they checked it and told me both O2 sensors are slow responding and something to do with air metering was off. About a month ago I posted a similar deliema and was told to disconnect my battery. I did that but the light came back about 30 miles later, and all that was wrong then was the first O2 sensor. I figured it was because i had lengthened that wire because i had put new headers in. But now i am not so sure that was the problem if both O2 sensors are bad. Could it be because I have a full exhaust,( Pacesetter Ceramic 4-1 headers, magnaflow high flow cat, and custom 2.25 pipping)? Should i still re-wire the first O2 sensor this weekend like i planed and see if it gets rid of that problem? Or should i just replace all 3 sensors and hope that helps? Any suggestions would help, thanks.

Shawn M.

PSN ID: Phatchance249

You have any problems with coolant levels?? If you have a coolant leak into the cylinders coolant destroys O2 sensors very quickly... I don't think it is b/c you have new exhaust...



Knowledge about everything and yet an expert of nothing!!
Jack of all trades.

My coolant levels were low. I went to buy more coolant thats why i was at AutoZone. But i think thats becuase I need a new water pump, and have never filled the coolant. The car has just under 50k miles so i hope i dont have coolant leaking into the engine. BTW mine is a sliver 01 Z, silver is the @!#$. Thanks for your imput, anyone else?

Shawn M.

PSN ID: Phatchance249

Dont just go out and buy all of them, the rear sensor is about 90$

I wasn't planning on it, and summit has them for $37 front and $53 in back. Or something like that. That would be a last resort. I am basically wondering if this is a problem seen before on here or maybe even a computer problem. Hopefully not. I am going to try my fix for the first one soon and prolly have to take it into a shop for the other two. Even though they will probably tell me to just get new sensors. Someone please help so i don't have to do that. Thanks

Shawn M.



And yes i know its only been a couple of hours since i posted, its just have been dealing with this for a while and its getting frustraiting. As always any help is appreciated.

PSN ID: Phatchance249

*Bump*

PSN ID: Phatchance249

Shawn McKenzie wrote:My CEL is on so i went into auto zone, they checked it and told me both O2 sensors are slow responding and something to do with air metering was off. About a month ago I posted a similar deliema and was told to disconnect my battery. I did that but the light came back about 30 miles later, and all that was wrong then was the first O2 sensor. I figured it was because i had lengthened that wire because i had put new headers in. But now i am not so sure that was the problem if both O2 sensors are bad. Could it be because I have a full exhaust,( Pacesetter Ceramic 4-1 headers, magnaflow high flow cat, and custom 2.25 pipping)? Should i still re-wire the first O2 sensor this weekend like i planed and see if it gets rid of that problem? Or should i just replace all 3 sensors and hope that helps? Any suggestions would help, thanks.

Shawn M.

Do you know the codes it was getting? Reason I ask is I had a slow response code from my first O2 sensor, and because fo it I was getting a code for my rear sensor (because I have full exhaust no cat). The second sensor was not seeing the difference it should. Once I replaced my first O2 sensor both codes went away. Also if you extended the wires on the first O2 sensor for the header, then that could be part of the problem. The stock wiring has resistance built into it. Adding wire throws that off. You can pull extra wiring out of the stock harness. I would put the wiring back together like stock to start off with. Clear the codes.



FU Tuning

Thanks John, I was going to re-wire the first O2 sensor this weekend closer to the origional configuration. I had thought that it would tell me the second one wasn't working b/c it didnt see a diffrence so if anything i will fix the first sensor first and see if it clears the second warning. Thanks for confirming that. The code for the first O2 sensor was PO133, but i didn't write down the two new codes. Thanks for the help guys and i hope to figure this all out this weekend. It is running like @!#$ and I am getting crapy gas milage.


I will post what i did to fix this so others can see it later. I am going to do it in stages to hopefully determine the problem.

Thanks.

Shawn M.

PSN ID: Phatchance249

Normally the O2 sensors arent bad, they dont fail as common as many people on here make it seem. If a code comes out, say PO171- that is system to lean bank 1. Autozone will say, oh holy @!#$ cars running lean, need an O2 sensor, dummy person, oh my god sell it right now, Autozone, oh yeah we got it in stock for you.

Now about a littel diagnosing here. If it says system to lean, it means the O2 sensor detected it was running lean. So you would more than likely have a vacuum leak.

Thats just with that code though.

Unless you have a scan tool, to actually see how how fast the O2 senosrs are switching I wouldnt even replace them. You could spend $150, replace the sensors, and have the CEL come on later that day, then you accomplished nothing.

Sometimes if you dont have the correct tool a shop is the best and only option.

By the way the rear O2 sensor should be staying lean, the thing is a efficency idicator only, it is not used for fuel metering at any point in time.




- 2004 Cavalier - 124k, owned since new

i always pop up codes p0133 and p0420 still havent figuerd out how to fix it .the upper 02 was changed mabye a year ago not even but i have been using an o2 simulator for the rear o2. any ideas on were to begin fixing this?

Rob S i dont know where you got the idea i was runing lean. The code i got said the sensor was "slow to respond" Meaning, from what i know about our engine, is the comp dumnps fuel in the engine to prevent running lean. Anyways i am going to re-wire the first O2 sensor better on saturday and clear the light to see if that does it. If that doesnt work then i am going to have to take it into a shop.

As for Chroma the code p0133 is the same one i got, 1st O2 sensor slow response. I am rewireing the sensor becuase i had to lengthen it already and didnt choose a good wire to extend it to the new point on the new headers. If you havent messed with the wire already i dont know what to say.

Thanks everyone for the adviece i will write again after i try my fix.

Shawn M.

PSN ID: Phatchance249

which side of the connector for the o2 sensor did you extend?

Both. The wire was too short to reach the hole on new headers. So i cut the wire about 4 inches from the end of the sensor. Saudered a new wire on, screwed the sensor in, cut the new wire to the length required to reach the other end of the origional wire. I probably left a little to much play in the new wire and that could cause the slow response. But as i said earlier i think the size of the new wire, type, and length are all combining to create my problem.

Shawn M.

PSN ID: Phatchance249

You can pull extra wiring out of the stock harness. what john said but mine 1 o2 still dose it then bought new one then it is still there when i cleared the code 100 times and still the po133 code and when i bought the car brand new then i was going to do a full cat back and headers that when it all started to srcew up and the car was new the wires are not short or cut. i starting to think this headers are not made right becz u have to move the o2 down more from the stock so wtf and i'm going back to stock soon to see if it is back to the way it was before . see yah

I just finished re-wireing the sensor with a wire of the same material, silver instead of copper, turnned it on and the light was gone! It runs perfect and no light after driving it around for about an hour. So i think i fixed it! Paul i had to lengthen mine and it doesn't seem to bother it, i just had the wrong type of wire. Thanks for all your input. Hope this helps future people.

Shawn M.

PSN ID: Phatchance249

i not lengthen mine wire i pulled the same as john did and the o2 i gone through was 4 of them and the car was new when i did this full catback and header pacesetter header and i still don't understand why is it throw po133 when the car is new when i bought it new in 2001 and when i started the full catback set up headers too then this po133 and when i start up my car from cold it always bongs down 3 times then idle normal i has to be this headers man i'm think the computer is not responding because of the air flow and the o2 is to far down the pipe more than stock so anyone know fix this ? or go back to stock so here is my problems.

1 po133
2 idle bongs down three times when cold start up.

I guess i was a little bit hasty on my assesment that i had fixed the problem. I drove for about 100 miles the day i fixed it, no problems. Today i started the car and 20 miles down the road the light came on again. Had it checked at autozone and the computer is throwing the same po133 code twice. Bank 1 sensor 1 slow response. What the crap !?!?!?!?!??!?! I think the only thing left is to replace the O2 sensor unless anyone has any more advice. Is there a way i can check to see if its the computer messing up?

Shawn M.

PSN ID: Phatchance249

then i guess there is no fix for this po133 with that pacesetter header on and if u as me get new o2 when i gone through four of them. and it is not short or grounded or add on wire.so anyone knows fix????

that same thing is happeaning to my car i did header back exhaust with pacesetter header and it bogs out and the o2 light keeps coming on. dont know what the deal is but was wondering if anybody could let me know on a fix for that problem

anyway as far as header maybe you can extend the sensor out like some people do on the cat? not sure what it does besides get it out of the "Direct flow" anyway maybe some kind of nut on the o2 sensor thread, and then put in in the bung so maybe its out 1/2'' more then stock? not sure if it does the trick on the header o2's tho

How could the sensor being in the direct flow cause a slow response warning light? Not trying to bash you, i am just getting really frustraited and confused as to why this seems to be limited to a few poor soles. I know lots of peps have the pacesetter headers, maybe because the old style was 4-2-1 and the new one is 4-1. I don't know, i guess i am going to replace the O2 sensor and hope that fixes it eventhough it sounds like it won't. Thanks for all the advice and keep it comming!!!!


Shawn M.

PSN ID: Phatchance249

So I just wrote an email to pacesetter telling them of our little problem and that it seems to be happening in multiple cases. Hopefully they will give us a fix or something. Or atleast fix it so others dont have to live with a CEL.

Shawn M.

PSN ID: Phatchance249

The following is an email response from pacesetter tech help about our little problem;

Hello , try cutting down the height of the O2 sensor fitting on the header, this
will move the O2 sensor more into the exhaust stream. The fitting is 18mm x 1.5, after you cut the height down, it is recomended to run a tap through to clean up the threads.

Anyone want to try this? Perferably the people who have already ruled out the posibility of a bad sensor.

Shawn M.

PSN ID: Phatchance249

people already do it.. its basically same thing i said except opposite i forgot yours was slow. people usually pop them out on the cat tho because its too high flowing for the sensor do wut they say tho and make it sit more in the stream

So i am going to be presumptuious and say i fixed my problem. I simply bought a new O2 sensor (because i had messed the wire up so bad by now and to eliminate the chance i just had a bad O2 sensor). I didnt have to cut and extend anything. I simply took the plug off its mounting point on the block and played with wire locations for litterally 2 min. And there was plenty of reach to simply connect the plugs. No cutting or anything. Hope this helps those out there that are having the same problem. I dished out $73 for the O2 sensor at the local Chevy dealer.

Shawn M.

PSN ID: Phatchance249