pj21086

iTrader: (24)

I got my 05 STi tuned today at s-squared and the air fuel ratios were jumping and nate couldnt get a good tune. He scanned for the cel and he told me that i needed a new 02 sensor.

Does anyone know if the Perrin o2 simulator would work in place of the messed up o2 sensor?

depdivr

I don't know if it will work in place of the O2 sensor but even if it did, I wouldn't use it for that purpose.

That sensor does go out on modified STIs after 20K miles or so. I am not sure why (mine did it at about 24K). It is a common problem. Just pay the $220.00 (I think that's how much it was) and fix the problem.

pj21086

iTrader: (24)

Yeah youre right. I found out that the front o2 sensor is how the engine knows whats going on. Thats why the afr's kept jumping. My STi only has 15k miles on it but im running cattless and with headers so maybe thats why it went out. I'm gonna go and buy a new one (it is 220) and then retune.

UK n00b

iTrader: (3)

It's possible you hit the sensor when installing the headers.

Something to add though is that if the sensor is bad then you should be getting ****ty gas mileage as it's main control of fuel is during closed loop operation and even failing O2 sensors should be more than fine for dyno tuning in open loop where the sensor has little to no input used.

I would guess if your gas mileage is as normal that you more than likely have a vacuum leak.

Mike

depdivr

Mike,
Your probibly right on the damage. Mine went out after "re"installing my headers. I had a exhaust leak from my first instalation so I had to redo it all. Anyway, lesson learned... take care of that 02 sensor when you pull it out, maybe put some tubing around the end to protect it when you pull it off???

pj21086

iTrader: (24)

When he was tuning my accessport, he told me that the afr's on his wideband were jumping. He said he would get a good tune and then when he went to run it again the number would be completely different. He said that they would jump to almost 20 and then the ecu would drop them back down to like 9 or 10.

I just went and bought a new o2 sensor and i wanted to know how to install it.

Oh yeah, my gas mileage sucks!

UK n00b

iTrader: (3)

Just unplug it at the top of the motor and undo the rataining clip connected to the coilpack and then use a wrench to remove the 02 from the header.

Should take you about 45 minutes tops.

pj21086

iTrader: (24)

Thanks for the help guys. I haven't done it yet but after I realized what i needed to do, it should be pretty easy. Thanks again.

depdivr

I am sure you probibly already know this but...

Before you pull your wheel and plastic stuff on the wheel well off, make sure you have a O2 sensor socket... otherwise you will have to put it all back on to go get one after you kill yourself trying to get it off with every other tool in your garage.