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View Full Version : Blown Catalytic Converter(s?)



joshespdx
06-04-2011, 12:19 AM
Here are a few specifics regarding my car before I give some background, a description of the current problem and ask a few questions:

1998 528i Automatic, 130,154 miles, Manufactured 11/97
VIN: WBADD6326WBW36194

I purchased the car at Zimbrick BMW in Madison, WI during October of 2008. The car was a single-owner car with 92,000 miles on the clock. All service had been done religiously at the dealer and it had never seen an accident. Aside from a very small, vertical door-ding on the passenger front door, the vehicle was flawless. The day I drove it off the lot (a Sunday), the CEL illuminated on the dash. Having just been filled with fuel, I wondered if it was vapor seal code. I turned around and went straight back to the dealer. Being a Sunday, no service techs were anywhere to be found. Frustrated, I went home and retrieved my Mac Tools OBDII code reader and hooked it up. One can imagine my frustration when the P0420 code popped (Catalyst Efficiency Below Threshold, Bank 1). Having in the neighborhood of 5,000 tech hours working on Honda's (Beaverton Honda in Oregon), I knew this wasn't good. I left a voice-mail for the salesman that I would be back first thing Monday morning.
What eventually ensued was drawn out battle of wills. They didn't want to fix this car because it was going to cost a fortune to do so. OEM catalytics and O2 sensors run in the neighborhood of $2000 to $3000 for the dealer, depending on metal and commodity prices. To make a long story short, I wound up with a set of DCS catalytic converters and the original O2 sensors. It took us 3 months to get to that agreement, one that I ultimately wasn't happy with. The catalytics came with a 2 year, 50,000-mile warranty that has since, come and gone.

Here's my problem: Over the past week or so, I've noticed some rattling when I start the car and under certain acceleration conditions. There was also a slight burble in the exhaust note at idle. I figured I had a rock rattling around somewhere, along with a loose clamp or a gasket that was going. I put the car up on some ramps today and started doing some old-school exhaust system troubleshooting by way of the rubber hammer. It didn't take long for the hammer to figure things out: my catalytics have started falling apart on the inside. As the innards get blown out the back, the exhaust is picking up a bit of a burble. It's not a good burble, but it might get there if I just let it be. Wishful thinking, me thinks. As a note, I throw a P0420/P0430 code about once every other month. Far less than expected, considering the circumstances.

Here's my question: Are there any legitimate mods that remove the catalytics and use dummy O2 sensors? Is there a source for dummy 02 sensors, or would I have to fabricate them from my existing sensors?

I've seen quite a lot of talk regarding the Magnaflow catalytics. Summit Racing list's two: 46105 and 53004. Any bias either way? The price difference is significant at $209.98 and $63.27, respectively.

In addition to this, I'd like to attempt the post-resonator exhaust removal. It looks pretty simple and those of you that have done it seem to be satisfied with it.

Thank you in advance for your responses. Also, my apologies in advance for asking about the Magnaflow's, as I have yet to make it through all of the posts regarding them.

Best,

Josh
Gig Harbor, WA

edjack
06-04-2011, 12:31 AM
I cannot envision either one to be of any quality, based on the price, especially the latter!

It appears, from what I've read, that most aftermarket cats only last that long.

You'll have to investigate WA's smog rules. I suspect it's illegal to remove the cats, and you'll get nailed at inspection time.

I have only one choice: buy only cats that are certified to be 50-state approved. It's illegal to install 49-state cats in CA.

Also in CA, it is the legal responsibility of the seller to make the car pass smog before title transfer.

m5hoot
06-05-2011, 08:32 PM
Sure, take the secondary cats out, you will have a constant CEL and you mileage will suffer. Suggestio0n, do mit right of skip it. Find a part car and look for a deal. Slow down and use common sense.

E39bmw
06-05-2011, 08:36 PM
actually your mileage will not suffer. I have 0 cats in my car and before cats removal, i used to get 25mpg highway and now (till 3 days ago) i started getting 26 to 26.5mpg

joshespdx
06-05-2011, 11:40 PM
Edjack: I'm not terribly disappointed by the service life of these catalytics. It's just one of those problems that there really isn't ever a good time for! Why the opinion of bad quality on the Magnaflows? The more expensive Magnaflow catalytic I listed is CARB approved. There seems to be mixed reviews from users here. I remember some of those smog rules from Cali; I'm glad I don't have to deal with those anymore! Washington only performs a OBDII check on 1996 and newer cars. You have to be "standing out" quite a bit to get them to take a look or, worse, run a tailpipe check. Oregon stopped tailpipe checks all together for two reasons: 1. they deemed it a health risk for the techs with the increase emissions levels at the testing center. 2. The dyno company that supplied the systems went belly-up. That being said, I have yet to see a tech look under a vehicle for catalytics.

M5hoot: I didn't quite get everything you wrote there. I'm keeping my eyes peeled for a part car. I set up a tracker for craigslist and eBay that sends me an update to my iPhone every 15 minutes. It's based on certain keywords that I ask it to look for. And I'm in no particular hurry. Part of doing my homework was coming here first for some good advice.

E39bmw: Is your CEL constantly illuminated, or did you use a work-around? Are your current miles-per-gallon a highway average or overall? My current highway mileage usually exceeds 30, and my overall is around 21 to 22mpg.

Thanks for the feedback everyone.

J

E39bmw
06-06-2011, 12:25 AM
My MIL (CEL) is always on and i dont care about it. That MPG is highway MPG calculated using Miles/gas used....dont trust OBC, that thing was telling me i was geting 30 all the time lol

edjack
06-06-2011, 12:37 AM
E39bmw,

How do you pass smog w/o cats?

m5hoot,

I don't believe that MY had secondary cats.

E39bmw
06-06-2011, 12:54 AM
I have connections