Does anyone have any ideas on how to access the Pre-Cat O2 (Drivers side) sensor on the 06 GT? I have a friend with super skinny arms that can touch it but no way at all to actually screw the new one in. This is being done from underneath with the exhaust pipe removed from after the cat. There is just barely enough room to touch the sensor but certainly no way to get a wrench or anything even close with the way we are trying to do this.

I have read over and over on how people have done it and some say from the top, others say from the wheel well, and some say from under and sadly some say you have to pull the engine. I am definitely not pulling the engine.

Any thoughts or ideas would be immensely appreciated.

 

Well.... the only work around would involve removing the catalytic converter from the turbo. There are four fasteners to remove. This would involve extensions, swivels and patience. Make sure to tie a string to the plug end of the O2 sensor. When removing the assembly this will maintain the proper routing behind the engine.

Please let us know what led to the assessment of a bad O2 sensor.

The chances of loosening let alone getting a socket on the O2 sensors while inside the engine compartment is close to Impossible.

 

It's a very strange story. I have been working on this car for over a year. I have completely rebuilt this car and it looks amazing. A few weeks ago I went for its first drive and it drove great but i noticed an odd exhaust sound and smelled exhaust in the car. I got the car on the lift and unbelievably, the O2 sensor was just dangling there. I do not even begin to understand how that happened. I'm guessing there was some repair done before me and maybe they just forgot to put that sensor in? I cant pretend to know how that got past someone. So the hole is just open and clearly thats not going to work.

As part of my trying to fix this stupid situation, I had been able to remove two of the four bolts from the turbo but I cant get the last two off. Even with extensions and a massive amount of patience. I dread the thought of getting those back on after getting all four of the bolts off.

 

Thank you for the reply.

Wondering out loud if the catalytic converter is bad? Has a proper scan been performed?

FWIW, dropping the engine is time consuming. The engine was designed to be removed. That being said not terribly difficult with the right equipment. The pain (for me) is removing & installing the bumper cover, radiator and air conditioning lines. For the O2 sensors lifting the car off the engine a couple feet will give access.

 

Take a look at the youtube video of the replacement: it's not easy.
See the thread I started a few months ago. My understanding is the other side is even more difficult to access.
My mechanic did it but it wasn't easy.

 

When I had my engine out to replace the turbo solenoid, I asked what else I should replace with the engine out, I did both (four?) O2 sensors, all were working, but at 70,000 miles, it was cheaper to just throw new ones in than to take the chance. So this is not a super-helpful comment but I thought you might find it interesting my independent jumped at the option to change them proactively with the engine out, presumably because of your problem. There just isn't any room to do much. Let us know how you figure it out.

 

I just spoke to the dealer which are great people in my town and they said that the Bentley manual says replacing any of the O2 sensors requires removal of the engine at $7,900.

A friend with really skinny arms was able to reach the sensor area (pre-cat) but there just isn't enough play in the pigtail to actually get it installed. With that said, someone in the room suggested we put in a dummy O2 sensor in the bung to eliminate the exhaust leak and call it a day. So we would have a dangling O2 sensor pre cat which would show NO O2 present and then a post cat O2 sensor properly installed showing whatever its showing (probably also no or little O2 considering it's post cat).

What would the end result be? Rough running engine? Any possible damage etc? The engine now with the dangling O2 runs great and sounds great. Maybe this is a temporary solution? I really don't know what to do, but i cant justify spending $7900 to literally screw a sensor in.

Any thoughts or brilliant ideas?

 

I imagine a check engine light at the least. I'm thinking through this, if you left it dangling, it would necessarily be reading far more O2 than expected (not "zero" as you stated) since it's just got atmospheric O2, not post-combustion 02. The ECU might try to adjust but I imagine it would be so far out of spec it would just error out.

I'll defer to Johnny.

But I can state that your estimate on how to replace it is probably right; that's why I had mine done when the engine was out, my independent said that when they failed, it was an engine-out job, might as well change it early.