P0430 and P0420 Catalyst System Efficiency Below Threshold bank 1&2

[bmwahba46]

I have an 02 530i with 113k miles on it.

Had these codes pop up on me 2 days ago, and I need some assistance in pin pointing where exactly the fault is.

These are telling me that either my 02 sensors have gone bad, or my catalyst is bad. However, PO told me that all 4 sensors were replaced. Should I take his word for it or should I replace pre cat and post cat sensors (again)? Or should I replace my cats?

I don't know any indy shops around me that can diagnose this issue by measuring the upstream and downstream the o2 sensors, so how else can I tell if it's the cats or the sensors?

What's weird is before getting these codes, I had code p0174 indicating bank 2 was too lean. I cleared codes and then these two codes came back.
Any help? Thanks.

[DHoang]

Take a look at the oxy sensors. Do they look new?
Are u a new onwer, how long have you had this car, and how many miles ridden before these codes popped up?

[Stück]

Cats are on the way out.

Do this:

http://www.energeticforum.com/renewa...n-foulers.html

A single non fouler is sufficient to make the cats very efficient. Two of them will make the DME happy with no cats at all.

Bank 2 lean is most likely part #17 here:
http://www.realoem.com/bmw/showparts...79&hg=11&fg=40

The vacuum cap dryrots, splits, and then causes bank 2 to go lean. Order and replace.

[bmwahba46]

Take a look at the oxy sensors. Do they look new?
Are u a new onwer, how long have you had this car, and how many miles ridden before these codes popped up?

I just took a look at them, I'm not sure how to judge if they look old or new?
Yes I'm a new owner. I've had the car for just about a month now. The lean code popped up after about 300 miles of driving when I bought the car. That code was on for about 20 days or so, and then just yesterday these 2 new codes popped up. I had the lean code diagnosed by the dealership and they told me it could be a 100 of things causing the lean code. From spark plugs to an air filter to bad cats.

Cats are on the way out.

Do this:

http://www.energeticforum.com/renewa...n-foulers.html

A single non fouler is sufficient to make the cats very efficient. Two of them will make the DME happy with no cats at all.

Bank 2 lean is most likely part #17 here:
http://www.realoem.com/bmw/showparts...79&hg=11&fg=40

The vacuum cap dryrots, splits, and then causes bank 2 to go lean. Order and replace.

I'll order that part and go ahead and replace it, but I should also mention that that code is no longer stored. I only have the p0430 and p0420 codes now.

[Stück]

It usually takes awhile to come back. Your O2 sensors are good, don't replace them.

[bmwahba46]

It usually takes awhile to come back. Your O2 sensors are good, don't replace them.

Regarding your comment that my cats are on the way out... is this 02 sensor mod just temporary until I get replacement cats?

[edjack]

Unusual for the I6 to eat its cats at this low mileage, unless they were physically damaged. Many of us will begin the diagnostics by replacing the post-cat sensors.

[bmwahba46]

Unusual for the I6 to eat its cats at this low mileage, unless they were physically damaged. Many of us will begin the diagnostics by replacing the post-cat sensors.

Yeah, I thought that was unusual as well. However, like I said, the PO says that he did replace all 4 02 sensors, and of course I don't have a problem with replacing them, but I would hate to spend money on unnecessary replacement parts, especially if there's a chance that they may have been replaced already.

[Stück]

I'm going to go with "sure" replace them as soon as you have $1500 laying around to waste.

The non foulers pull the O2 sensor out of the exhaust gas stream, making it read as if the exhaust gas is MUCH cleaner than it is. The precat sensors are for the DME, the postcat sensors are only for emissions.

[16valex]

Don't waste your money and labor on the non-fouler plugs, they won't work on E39 software. I've been there and done that. At a 113K miles is a little too early for CAT to go but then again it all depends on how the car has been maintain.

[bmwahba46]

I'm going to go with "sure" replace them as soon as you have $1500 laying around to waste.

The non foulers pull the O2 sensor out of the exhaust gas stream, making it read as if the exhaust gas is MUCH cleaner than it is. The precat sensors are for the DME, the postcat sensors are only for emissions.

$1500? Is it a bad idea going with aftermarket cats? I expected new aftermarket cats to be around $200-300....

[Stück]

Don't waste your money and labor on the non-fouler plugs, they won't work on E39 software. I've been there and done that. At a 113K miles is a little too early for CAT to go but then again it all depends on how the car has been maintain.

I'm so damn tired of the ignorant sh!t people around here say. "It won't work on E39 software" is ignorant, plain and simple. I've been there, done that, and know many others with the same experience. It works VERY well with ANY car. Has worked just fine for the last 30,000miles on my E39. O2 sensors aren't magical. Pull the sensor head out of the exhaust gas stream and it WILL read cleaner. Pull it even more out and it will ready super clean. I have a friend that has headers on his E39 525i (no cats), doubled up non foulers, and NO CEL. The O2 sensors are reporting very healthy numbers.... If you want it to read as clean as possible than only drill out the non fouler bore as little as possible so it thoroughly chokes exhaust gas flow to the sensor head.

$1500? Is it a bad idea going with aftermarket cats? I expected new aftermarket cats to be around $200-300....

The stock exhaust manifolds are intergrated with the catalysts. There really isn't room for some aftermarket unit in there given the construction.



Each one of those manifolds is 7-800 new at the dealer. Even if there was an aftermarket cat that was purpose made to fit in this exact application the manifolds would still have to come off the car which is a legitimate full days labor to R&R at an exhaust shop, not counting the cutting/welding to be done.

[bmwahba46]

I'm so damn tired of the ignorant sh!t people around here say. "It won't work on E39 software" is ignorant, plain and simple. I've been there, done that, and know many others with the same experience. It works VERY well with ANY car. Has worked just fine for the last 30,000miles on my E39. O2 sensors aren't magical. Pull the sensor head out of the exhaust gas stream and it WILL read cleaner. Pull it even more out and it will ready super clean. I have a friend that has headers on his E39 525i (no cats), doubled up non foulers, and NO CEL. The O2 sensors are reporting very healthy numbers.... If you want it to read as clean as possible than only drill out the non fouler bore as little as possible so it thoroughly chokes exhaust gas flow to the sensor head.

The stock exhaust manifolds are intergrated with the catalysts. There really isn't room for some aftermarket unit in there given the construction.

Each one of those manifolds is 7-800 new at the dealer. Even if there was an aftermarket cat that was purpose made to fit in this exact application the manifolds would still have to come off the car which is a legitimate full days labor to R&R at an exhaust shop, not counting the cutting/welding to be done.

Yeah, well that is definitely out of the question then.

For the non fouler mod, is that to be done on the two post 02 sensors?

[Stück]

Post cat sensors, yes. Bore them out per that link but only just big enough to clear the O2 sensors head. Less flow getting to them the better.

[bmwahba46]

Post cat sensors, yes. Bore them out per that link but only just big enough to clear the O2 sensors head. Less flow getting to them the better.

I see. I don't have access to a drill press, should I take it to a machine shop to do it or are there any other ways to DIY?

Also, Schtook, I ordered the valve cap (part #17 that you mentioned earlier), I can't seem to find that part on the manifold like shown in the diagram, can you give me an idea as to where it's located exactly?
Thanks

[Stück]

You don't have a vise and a cordless drill? That's how I've done it before. They are soft steel.

It is on the back of the manifold, directly facing the firewall. There are several other vacuum ports there that are smaller, but the big guy is the one that always fails.

[bmwahba46]

You don't have a vise and a cordless drill? That's how I've done it before. They are soft steel.

It is on the back of the manifold, directly facing the firewall. There are several other vacuum ports there that are smaller, but the big guy is the one that always fails.

Oh, yeah, nevermind then. Did you have to use a 1/2" drill bit in order for the bore to be only just big enough to clear the O2 sensors head?

[Stück]

I don't recall the size off the top of my head, but 1/2" is a bit too big. O2 sensors vary in size and shape.

[bmwahba46]

I don't recall the size off the top of my head, but 1/2" is a bit too big. O2 sensors vary in size and shape.

Ok, no problems. Will update this thread in the near future regarding how this goes. Thanks for the help so far!

[16valex]

I'm so damn tired of the ignorant sh!t people around here say. "It won't work on E39 software" is ignorant, plain and simple.

Hey shfuch! Take it easy! I had the suckers in my 97-M52 with DEC CATs and it didn't work, still have the dreaded Cat efficiency. Maybe your M54 has better luck than me, but to call out someone ignorant is definitely hostile to me.

[Stück]

Those DEC cat/manifolds are about the worst thing I've ever seen. Makes the factory part look like a work of art!
http://pictures.deccats.com/BMW1402F.jpg

Ignorant is the word for it, siting "software" being my primary point. Mind you I didn't call you stupid, or a moron, or the like.

The MS43 DME is not some supercomputer that can sense you repositioned the O2 sensor. Pull it out of the stream, don't overbore the non fouler, and it won't be an issue! I know so many cars running setups like this, even with NO CATS what so ever.

An even better trick is to flash the DME to stop looking for or caring about the rear O2 sensors at all. When I recently swapped a 2006 330i ZHP engine into my 01 525i, (along with a 6MT that people said can't be done...) I fitted good low mileage used manifolds, but deleted the rear O2 sensor monitoring altogether in the DME's software.

[bmwahba46]

Those DEC cat/manifolds are about the worst thing I've ever seen. Makes the factory part look like a work of art!
http://pictures.deccats.com/BMW1402F.jpg

Ignorant is the word for it, siting "software" being my primary point. Mind you I didn't call you stupid, or a moron, or the like.

The MS43 DME is not some supercomputer that can sense you repositioned the O2 sensor. Pull it out of the stream, don't overbore the non fouler, and it won't be an issue! I know so many cars running setups like this, even with NO CATS what so ever.

An even better trick is to flash the DME to stop looking for or caring about the rear O2 sensors at all. When I recently swapped a 2006 330i ZHP engine into my 01 525i, (along with a 6MT that people said can't be done...) I fitted good low mileage used manifolds, but deleted the rear O2 sensor monitoring altogether in the DME's software.

Isn't it slightly bad however that I am using this non fouler mod to essentially ignore a bad cat? I mean, I think it's great that I can get rid of these codes with such ease and low cost, but isn't ignoring a bad cat a bad idea in the long run?

[Stück]

So long as the cat isn't clogged it isn't BAD IMO.

Over time the precious metals in the cat wear out and cause its efficiency to drop. You aren't being as kind as you possibly could to the environment, but by no means are you pumping out raw gas either...

This should work for a year or two, at which point you might not even have the car anymore.

Used manifolds are certainly a more cost effective option but you have no real way to know how many miles are on them, or if they are any good. It is a MAJOR job to R&R these suckers and how much would it suck to install a used set and have the same problem...

[bmwahba46]

So long as the cat isn't clogged it isn't BAD IMO.

Over time the precious metals in the cat wear out and cause its efficiency to drop. You aren't being as kind as you possibly could to the environment, but by no means are you pumping out raw gas either...

This should work for a year or two, at which point you might not even have the car anymore.

Used manifolds are certainly a more cost effective option but you have no real way to know how many miles are on them, or if they are any good. It is a MAJOR job to R&R these suckers and how much would it suck to install a used set and have the same problem...

I see.

Well I definitely have no plans of replacing this car anytime soon.
Regardless I'll still do this for the time being and if worse comes to worse maybe I'll just remove the cats completely if and when they do go bad.

[16valex]

Those DEC cat/manifolds are about the worst thing I've ever seen. Makes the factory part look like a work of art!
http://pictures.deccats.com/BMW1402F.jpg

Ignorant is the word for it, siting "software" being my primary point. Mind you I didn't call you stupid, or a moron, or the like.

The MS43 DME is not some supercomputer that can sense you repositioned the O2 sensor. Pull it out of the stream, don't overbore the non fouler, and it won't be an issue! I know so many cars running setups like this, even with NO CATS what so ever.

An even better trick is to flash the DME to stop looking for or caring about the rear O2 sensors at all. When I recently swapped a 2006 330i ZHP engine into my 01 525i, (along with a 6MT that people said can't be done...) I fitted good low mileage used manifolds, but deleted the rear O2 sensor monitoring altogether in the DME's software.

So you know a thing and two about BMW software and you think you're a hot shot! Listen son, at then end of the day you're what you are still have to wake up and go to work, listen to the wife and her to do list, and if you have children about to go college you will be worry how the heck you're gonna pay for that.

Be humble!