Catalytic converter question/problem.

[Gatt9]

Hi all,

Last year I switched to a set of Pacesetter headers with a 3" in/out Magnaflow cat and a 2.5" Magnaflow catback. Everything seemed fine.

In the summer, I redid my valve covers, removing the EGR. Took me weeks to reseal the damn thing. During the time I started getting SES codes "EGR circuit low" and "Cat below threshold". Got the EGR resealed. The SES and "Cat below threshold" wouldn't go away.

After a few weeks my passenger side O2 sensor went bad. I was running a bit rich. Kept going because I didn't have money thanks to tuition. Recently the O2 sensor completely died, and was just sucking down fuel and blowing it out the tailpipe. It was only like that for 1 1/2 days. Luckily I had bought a set of Denso O2's and was just trying to fit in the replacement. So I got the O2 sensor replaced.

SES lights were out, for about 2 days. Back on again, with "Cat below threshold".

Any ideas? Bad Cat? Because of my headers? It's my only code.

Thanks all for any suggestions, as always it's much appriciated!

Gatt

[bigbrian442]

Re: Catalytic converter question/problem.

Do you know if you got an OBDII approved CAT? Easiest thing would be to have the code tuned out.

[loser]

Re: Catalytic converter question/problem.

running too rich WILL kill your cat, factory or aftermarket.

are you running a post-cat 02? some cars will always throw codes due to the highflow cat being there.

[Gatt9]

Re: Catalytic converter question/problem.

I'm afraid I don't know if it was OBD2, it was a carsound Magnaflow, if that helps. Bought it on E-bay, though a friend is telling me that it was old packaging and she thinks might be a rebuild of some sort or something that was on a shelf for awhile.

I was running *way* too rich, like I could see the film of gas on the melted snow behind the car too rich, the last day and a half and I could smell overheated metal on the two trips I took.

I do have a post-cat O2, But the SES light wasn't on for the first 5 months, not till I had the EGR leak and was throwing "EGR circuit low". I'd gotten the impression it was possible to have silent SES codes though? Ones that don't turn on the light?

I was wondering though if it could be the whole new exhaust and the difference in flow/backpressure?

I'll end up getting a copy of HPTuners, but not till mid-february, and emissions is due by Jan 31st. That's why I figured I'd check here first.

Not sure if it's pertinent, but while the O2 sensor was going bad, I'd go a period of a couple weeks without SES lights, and then it'd immediately pop up if I had someone in the passenger seat. Struck me as very odd...

Ty all for your help!

[bigbrian442]

Re: Catalytic converter question/problem.

Magnaflow has both OBDII approved and non OBDII approved CATs.

After CAT sensor could be going bad.

CAT could have gone bad from all the extra fuel going through it.

Ive heard of people getting the CAT below threshold code from low back pressure exhaust, but mainly the complaints were from people that went with 3".

I have Pace Setters, A 3" OBD II approved Magnaflow Carsound cat and 3" Borla CAT back and haven't gotten a CAT code in the 2 years it's been on.


Here if you fail the emissions test first time they give you 6 months to get it re tested. If you fail the re test, you get 30 days for the next re test until you either spend enough on repairs to get a waiver or you can keep getting it re tested every 30 days.

I have HP tuners with the 98 model year license but I'm about 4+ hours away.