Trying to Pass Smog using O2 extender

[Fernando Escobar]

good morning, ladies and gents.
I am having an issue and I was hoping to get some wonderful feedback from you.

After I rebuilt my engine, I am having an issue with my cat on bank one. Can’t clear the code. I swapped out the O2 sensors for a brand new OEM‘s problem still consisted..

So before I went on vacation, ordered the O2 exhaust extenders hoping that this would help me. I installed the extenders on Pre and post cat, i drove to clear codes and now I have a P015D code. my scanner gave me a some freeze frame info and the voltage on bank one Pre cat. The voltage is way off compared to the others. This is the brand new sensor mind you.

So my question is, should I remove the extender on the pre o2 cat cause maybe the culprit was the post o2 yeah cat?
I will eventually change the catalytic converter, but I wanna be able to have the next two years to save up the money for it since these cats on a 13 GMC Denali are $5000

I will post the pictures from the data. See what you guys tell me. My other issue is my OBD two reader shows 44 PSI the car supposedly at the time of the freeze frame was going 44 miles an hour so it just seems like a lot of low pressure. I also know that that low fuel pressure on rare occasions can activate an O2 issue.

thank you for your time. Hopefully someone would be able to help.

 

[Marky Dissod]

Switch the left and right O2 sensors. If the data remains the same, either you've an electrical wiring problem,
or your catalytic converter needs replacing.

 

[Fless]

BOTH banks are calling for LOTS of fuel to be added (lean condition).

Are you sure that the intake tube is sealed properly, and that no unmetered air is getting in before the throttle body? What is the MAF reporting at hot idle, in g/sec?

Any exhaust leaks?

 

[j91z28d1]

I don't believe the o2 extenders are for the pre cat, they are more ment to slow down the rear o2 signal so the ecm thinks the cat is. working.


on another note, I. agree your trims are all out of wack. by rebuilt engine, can you give some. details? did you put a aftermarket cam in it? any possible exhaust leaks at the exhaust manifolds?

 

[Fernando Escobar]

BOTH banks are calling for LOTS of fuel to be added (lean condition).

Are you sure that the intake tube is sealed properly, and that no unmetered air is getting in before the throttle body? What is the MAF reporting at hot idle, in g/sec?

Any exhaust leaks?

Ill check

 

[Doubeleive]

good morning, ladies and gents.
I am having an issue and I was hoping to get some wonderful feedback from you.

After I rebuilt my engine, I am having an issue with my cat on bank one. Can’t clear the code. I swapped out the O2 sensors for a brand new OEM‘s problem still consisted..

So before I went on vacation, ordered the O2 exhaust extenders hoping that this would help me. I installed the extenders on Pre and post cat, i drove to clear codes and now I have a P015D code. my scanner gave me a some freeze frame info and the voltage on bank one Pre cat. The voltage is way off compared to the others. This is the brand new sensor mind you.

So my question is, should I remove the extender on the pre o2 cat cause maybe the culprit was the post o2 yeah cat?
I will eventually change the catalytic converter, but I wanna be able to have the next two years to save up the money for it since these cats on a 13 GMC Denali are $5000

I will post the pictures from the data. See what you guys tell me. My other issue is my OBD two reader shows 44 PSI the car supposedly at the time of the freeze frame was going 44 miles an hour so it just seems like a lot of low pressure. I also know that that low fuel pressure on rare occasions can activate an O2 issue.

thank you for your time. Hopefully someone would be able to help.

it won't pass smog with extenders, if you can get the code to go away you might be able to remove the extender and stick it back in just before you pull up for the inspection..
maybe.....(doubtful)
however you can pass with 1 code pending...

 

[OBSandaNNBS]

good morning, ladies and gents.
I am having an issue and I was hoping to get some wonderful feedback from you.

After I rebuilt my engine, I am having an issue with my cat on bank one. Can’t clear the code. I swapped out the O2 sensors for a brand new OEM‘s problem still consisted..

So before I went on vacation, ordered the O2 exhaust extenders hoping that this would help me. I installed the extenders on Pre and post cat, i drove to clear codes and now I have a P015D code. my scanner gave me a some freeze frame info and the voltage on bank one Pre cat. The voltage is way off compared to the others. This is the brand new sensor mind you.

So my question is, should I remove the extender on the pre o2 cat cause maybe the culprit was the post o2 yeah cat?
I will eventually change the catalytic converter, but I wanna be able to have the next two years to save up the money for it since these cats on a 13 GMC Denali are $5000

I will post the pictures from the data. See what you guys tell me. My other issue is my OBD two reader shows 44 PSI the car supposedly at the time of the freeze frame was going 44 miles an hour so it just seems like a lot of low pressure. I also know that that low fuel pressure on rare occasions can activate an O2 issue.

thank you for your time. Hopefully someone would be able to help.

The cats are FIVE GRAND?!

 

[Fernando Escobar]

BOTH banks are calling for LOTS of fuel to be added (lean condition).

Are you sure that the intake tube is sealed properly, and that no unmetered air is getting in before the throttle body? What is the MAF reporting at hot idle, in g/sec?

Any exhaust leaks?

Ill check in

The cats are FIVE GRAND?!

CA CARB ones yes.

 

[Doubeleive]

Ill check in

CA CARB ones yes.

no... you need to find another shop, you can get one welded in for around $650 (carb compliant)
just ask for a catco. A brand new oem y pipe is about $3200
whoever told you $5k is a thief

 

[Coveman]

vv

 

[Coveman]

I don't believe the o2 extenders are for the pre cat, they are more ment to slow down the rear o2 signal so the ecm thinks the cat is. working.

This. You dont want to extend the pre-cat sensor as it may cause the system to sense a false lean condition and up your fuel trims.

 

[justirv]

The cats are FIVE GRAND?!

I got Magnaflow CA CARB cats with Y-pipe (single assy) a few years ago for about $1k, I see that same P/N is near $3k now. I like @Doubeleive 's suggestion.

 

[OBSandaNNBS]

I got Magnaflow CA CARB cats with Y-pipe (single assy) a few years ago for about $1k, I see that same P/N is near $3k now. I like @Doubeleive 's suggestion.

That's about what I saw. I'm wondering if 5K is the "I don't want this job" price.
Either way, find a new shop @Fernando Escobar

 

[Doubeleive]

I got Magnaflow CA CARB cats with Y-pipe (single assy) a few years ago for about $1k, I see that same P/N is near $3k now. I like @Doubeleive 's suggestion.

yes the magnaflows went up and they have a price lock across all authorized dealers which is illegal but nobody does anything about it........
catco is the cheapest (for the 6.2l), walker makes some cheaper but only for the 5.3l
ap/eastern owns both, so between eastern and magaflow and oem is your only options for carb cats
it is illegal to sell them used from a yard but money talks, once in a blue moon you might see some on CL or something
otherwise try to score from someone parting one out from there backyard or something.....
has to be the right year range
federal ones are cheap but won't pass in cali

 

[RET423]

Okay you don't mess with the pre cat O2 sensors, pulling them out of the exhaust stream will report a false lean & the ECM will dump fuel like mad trying to correct it

O2 extenders work by pulling the post cat sensor away from the exhaust stream so it reports more oxygen that the pre cat sensor; which tells the ECM that your cat is working well; even though it's not

The pre cat O2 sensor is how the ECM fine tunes the engine, if you mess with that you screw up your engine, the post cat O2 sensor is only there to compare readings with the pre cat sensor to determine if the cat is still functioning or needs replacement; it plays no role in the engine tuning

 

[Fernando Escobar]

Okay you don't mess with the pre cat O2 sensors, pulling them out of the exhaust stream will report a false lean & the ECM will dump fuel like mad trying to correct it

O2 extenders work by pulling the post cat sensor away from the exhaust stream so it reports more oxygen that the pre cat sensor; which tells the ECM that your cat is working well; even though it's not

The pre cat O2 sensor is how the ECM fine tunes the engine, if you mess with that you screw up your engine, the post cat O2 sensor is only there to compare readings with the pre cat sensor to determine if the cat is still functioning or needs replacement; it plays no role in the engine tuning

Thanks
I removed the pre cat extender and all diagnostics are ckeared and ready to go!
I did a DOD delete on this trck and swore i erased the vlom codes through hp tuners but they show up as permanent codes. My smog gu said keep driving it but im tempted to put the old vlom back in so its plugged in and pass smog alread.
What do you guys think?

 

[Fernando Escobar]

yes the magnaflows went up and they have a price lock across all authorized dealers which is illegal but nobody does anything about it........
catco is the cheapest (for the 6.2l), walker makes some cheaper but only for the 5.3l
ap/eastern owns both, so between eastern and magaflow and oem is your only options for carb cats
it is illegal to sell them used from a yard but money talks, once in a blue moon you might see some on CL or something
otherwise try to score from someone parting one out from there backyard or something.....
has to be the right year range
federal ones are cheap but won't pass in cali

Yeah on rock auto only the cats for the 13& 14 model year will fit in this 6.2. find 5.3 on Facebook marketplace all day.

 

[justirv]

Thanks
I removed the pre cat extender and all diagnostics are ckeared and ready to go!
I did a DOD delete on this trck and swore i erased the vlom codes through hp tuners but they show up as permanent codes. My smog gu said keep driving it but im tempted to put the old vlom back in so its plugged in and pass smog alread.
What do you guys think?

When you erase codes you reset the emissions flags. You need to do the appropriate drive cycles to clear these flags to pass smog. There are several guides online as to the process to follow to accelerate smog readiness. Evap is typically the longest to clear, and may take up to 200-300 miles of driving. I have been successful in clearing most of my vehicles within 50-100 miles.

 

[Fernando Escobar]

When you erase codes you reset the emissions flags. You need to do the appropriate drive cycles to clear these flags to pass smog. There are several guides online as to the process to follow to accelerate smog readiness. Evap is typically the longest to clear, and may take up to 200-300 miles of driving. I have been successful in clearing most of my vehicles within 50-100 miles.

Yeah, they are all cleared now even the evap, but i have the permanent codes from the cylinders that used to be used for the AFM/DOD.
So i was thinking of removing the ls2 valley cover i plaved and reinstall the AFM VLOM to hopefully trick the computer its still plugged in to AFM.

 

[Fless]

I'm not familiar with HP Tuners but doesn't it have a way to set the PCM to ignore those codes?