Catalytic Converter question

LBarr2002 · Sep 25, 2019

My mom's '07 Yukon XL has been having some issues. It had a misfire on the right bank (#6 I think). They changed plugs, wires, and I think intake gasket and got that straightened out. Shortly after it started throwing P0430, catalyst below efficiency bank 2. Our thoughts are the misfire may have ruined the converter?

Bank1

Bank2

Anybody ever see a converter look like that? What would cause it?

We bought an Evan Fischer REPC960340 replacement cat pipe from carparts.com's ebay store. Dad swapped it out over the weekend and yesterday it threw P420 and P430. So it doesn't like these converters or they're not "doing enough"?

Thoughts?

97TJGUZZY · Sep 26, 2019

could it be a bad 02 sensor?

LBarr2002 · Sep 26, 2019

He swapped downstream sensors side to side before changing the converters and the code stayed on bank 2. The drivers upstream couldn't come out without removing more stuff, so he didnt swap up streams. But, code staying on bank 2 and now codes on both sides rules that out in my mind.

LBarr2002 · Sep 26, 2019

Dad went by a local shop that he knows the owner and mechanic well. They said they've run into this before where the aftermarket converters aren't efficient enough for the computer. They won't install anything but OEM, and said nobody ever pays for OEM. They have a junkyard supplier that with customer approval they'll put OEM junkyard ones on.

97TJGUZZY · Sep 27, 2019

So is he going to go with an OEM replacement?

LBarr2002 · Sep 27, 2019

97TJGUZZY said:

I think the 2 options right now are junkyard OEM if he can get one, possibly tune to cut off downstreams if he can't.

Twilliamson · Sep 30, 2019

I would think o2 Simulators would be the cheapest option.

LBarr2002 · Sep 30, 2019

Twilliamson said:

Did you see any that look legit for a decent price? $100 to tune it out.

Twilliamson · Sep 30, 2019

I'm not sure which ones it would need, i have made several sets for mustangs.. its just a resister....

jimbo92 · Sep 30, 2019

Throw an aftermarket cat on it and take it to v8muscle.net in piedmont and have that hting tuned. Turn off DOD while you;re in there.

LBarr2002 · Sep 30, 2019

jimbo92 said:

I knew that would be your answer. I've already talked to Charles and he'll do it, just not 100% sure that's what dad wants to do yet. I filed a return request with ebay to see if he can get any money back on it, so the aftermarket ones may come back off.

LBarr2002 · Oct 28, 2019

Resolution on this.

Ebay granted a return and dad shopped around for another brand that had good results. We ordered a Bosal 079-5218 from Summit. In the meantime, Dad got pneumonia and was pretty much down for a couple weeks. Friday a week ago he finally felt up to tackling changing it again, returned the Evan Fischer and it's fixed.