LLT Sv6 Pre Cat o2 sensor Removal

[Grapejuice47]

Hey guys,
First post here hope this hasn’t been covered before (if so I apologise)
Anyways I’ve been having issues with idle so decided I might see if new pre cat o2 sensors might do anything

However they are impossible to open
I’ve bought those o2 sensor socket tools but it’s not enough, like this thing is pretty much welded on lol

Has anyone removed these ones before ? If so, any tips or tricks would be highly appreciated
If unclear this is the o2 sensor right after the headers
Thanks

 

[syked]

Yes I've changed mine before. Do you have the deep socket type or L shape type? I think it's easier with the deep type which is what I used. Use a long extension with a breaker bar and even a pole on the breaker bar for extra leverage.

New O2 sensors should have anti-sieze compound on the thread or some might have a separate grease packet for this purpose but don't apply the grease to the actual sensor part.

Correct...they sit near the exhaust headers.

 

[syked]

As for your idle issue, this can be a number of issues.

What diagnosis has occurred thus far?

 

[vr304]

Will be easier with some heat mate run the engine for a while then try with some good gloves like welding gloves so not to burn ur hands

 

[Grapejuice47]

Yeh I have the deep socket type
However it didn’t seem to grip the sensor too well
I made sure it was seated right but it just slipped

 

[Grapejuice47]

As for your idle issue, this can be a number of issues.

What diagnosis has occurred thus far?

Well basically during low rpms my ltft (long term fuel trim) is like more than 20 (running lean) which is resulting in poor idle and really poor fuel economy
At first I assumed it was a vacuum leak but couldn’t find anything
Also once when I scanned it apparently both of the pre cat o2 sensors had heater circuit issues
That code never came back up again but it’s worth a try I guess coz honestly I’m out of ideas lol

 

[vr304]

O2 sensors are a service item and do need to be replaced over time (about 5 years I think)

 

[Grapejuice47]

O2 sensors are a service item and do need to be replaced over time (about 5 years I think)

Yeh so this weekend I’m going to try opening them up and replace them praying that it’s as simple as that

 

[syked]

Well basically during low rpms my ltft (long term fuel trim) is like more than 20 (running lean) which is resulting in poor idle and really poor fuel economy
At first I assumed it was a vacuum leak but couldn’t find anything
Also once when I scanned it apparently both of the pre cat o2 sensors had heater circuit issues
That code never came back up again but it’s worth a try I guess coz honestly I’m out of ideas lol

Do you remember what the o2 sensor voltages were during your live scan?

How did you check for vacuum leaks?

Could also be a MAF issue

Change your O2 sensors and see how you go I guess

 

[Grapejuice47]

Do you remember what the o2 sensor voltages were during your live scan?

How did you check for vacuum leaks?

Could also be a MAF issue

Change your O2 sensors and see how you go I guess

For vacuum leaks a sprayed flammable liquids at every connection and seal after the air sensor
I even tried it with propane gas and no change in rpm

Maf seems to be running fine and it’s values change according to rpm as it should

The o2 voltages where all over the place it never kept a steady curve
I tried keeping rpms steady

Right now my car has a bank 1 sensor 1 heater circuit code
As well as a bank 2 lean code

Nothing’s making sense lol