WTH?! Replaced o2 sensor, CEL light still on...

[90CherryTSI]

Code 11 on a 1g. I replaced it with a BOSCH universal. If the ground leads are reversed would it cause this? It's all connected right, and when I would reset the CEL light it'd take about a day to come back on, same thing after I replaced the sensor. About a day after replacing, CEL light back on, code 11. Any ideas? Only thing I can guess is MAYBE I swapped the two black grounds....it's a 4 lead sensor, it matches up...

 

[1990CherryTSI]

Maybe unrelated but my turbo just went out. Would a faulty o2 sensor play any role in this whatsoever? I can't see it but who knows....ideas, please....kill the crickets chirping and chime in....anyone....

 

[mitsutuner]

here is a link that explains the O2 sensor wiring, see if that helps.
What are symptoms of the turbo going out? My first guess is that something was loosened &/or moved out of the way to get to the o2 sensor wiring connector--doublecheck all the turbo & IC plumbing & clamps as well as the wiring that goes to the 3 sensors on the thermostat housing & the wiring that goes to the O2 sensor where it's clamped to the exhaust manifold heatshield--check for damaged insulation & doesn't have to be clamped very tight & then bend the clamps upward to hold the wire as far away from the heat shield as possible.
You mentioned chirping--is that a sound coming from the turbo or the ECU which is behind the radio.

Assuming you removed the heat shields to change the O2 sensor, did you take a close look at your cast iron exhaust pieces for fractures & tighten all their connecting bolts? Not related to your current problem, just problems I found on mine in the past.


http://www.ecanfix.com/~mdhamilton/o2sensor.html

 

[90CherryTSI]

I had a manual but it didn't explain that white was negative and blue positive. In the harness though it goes from blue to red on the side of the engine, the wire changes color. I assume it doesn't really matter. And to be honest since I got the car it only put out like 8 lbs of boost but seemed weak. Then with the manual boost control and gutting the cat I got it up to about 13-14. I didn't have any squealing or weird noises ppl say the turobs make, it just plain and simple died. I assume the poor boost was partially related but won't know. I have another coming but the o2 sensor light worries me as ppl say that can be part of the problem all around with it not wanting to run "right" and all. I need to test voltage on it and all that just to see maybe where a problem could occur. I haven't done all that yet but I can't imagine....white to white, blue to red just like the stock sensor, black to black, and black to black...do you know if reversing the black and black ground vs positive for the heater element would make the light come on? I can't find a site that would explain reasons the light comes on other than....o2 sensor....any ideas on that?

 

[mitsutuner]

For sure the car won't run right without the correct O2 sensor output because the ECU uses the O2 input to calculate proper air/fuel ratio, which it controls by setting the time duration that the fuel injecters are spraying fuel into the cylinders. It doesn't seem like you could do anything fatal by experimenting with different wiring configurations until it works right. It's my understanding that the extra 2 wires that go to the heating element inside the sensor are not essential since the heater only comes into play during warm-up, when the cold sensor has not yet been warmed up by the exhaust gas. I used a denso sensor with OEM connecter from Intex Auto Parts,(google will find it for you). It was under $60 & "plug & play" & gave no error codes.
For your turbo failure, I don't really understand the how & why, but if the failure occurred at the same time as your O2 sensor change, then there must be a relationship. What I do know, is that at the tailpipe, the exhaust comes out with less force if the fuel mixture is too rich & this of course would affect the turbo performance. If I recall correctly, in the absence of O2 sensor output, the fuel mixture will indeed run rich. I would also guess that maybe the mis-informed ECU is keeping the wastegate open via the BCS? As a safe mode precaution?
I think what you want to do is correct the O2 sensor problem first & then see what's happening with the turbo.

 

[Mike1992]

remember not to hardwire the connections solder them

On the other hand i replaced my 02 sensor a few months back and turned out a i had 2 cut wires about a foot back on that 02 harness, at first i just hardwired and got bad readings, then I went back and soldered and now things are great

 

[leet]

Some DSMs ECUs are notorious for taking FOREVER to reset themselves.

Mine suffers from this.

 

[mitsutuner]

I read somewhere that it should take about 5 restarts & drives to reset the ECU because it compares average readings.
Very nice looking engine bay you got there Mike, who painted your valvecover? & btw, kinda hard to tell from the pic, but it looks like your spark plug wires might be resting against the valvecover. Where did your cool header pipes come from?

 

[Mike1992]

Very nice looking engine bay you got there Mike, who painted your valvecover? & btw, kinda hard to tell from the pic, but it looks like your spark plug wires might be resting against the valvecover. Where did your cool header pipes come from? [/B]

Thanks! I painted the valve cover myself, after doing up 2 and selling them on ebay, I thought I deserved one for myself The wires are resting on that back right corner a little, Is that bad? The header is pacesetter, just like the rest of my exhaust, headers been ported/exhaust wrapped/silicone sprayed (rust prevention) Once again thanks!

 

[mitsutuner]

My understanding of spark plug wire routing is that you don't want them to touch anything that's hot because it will break down the insulation & could result in misfires. Also, you don't want the wires to be touching each other because some EMF(eddy current) is present even outside perfectly good insulation--that's how the timing light works when it's merely wrapped around a spark plug wire.
When I'm at the junkyard, I fill my pockets with the white nylon seperaters that mazda uses to seperate vacuum lines, there's 2 or 3 of them on every 323.
Yeah, you have a great looking engine bay--it's obvious a lot of attention has ben paid to detail.