So I just went to smog…FAILED, Advice?

[schröe30er]

The only cheap fix is to fix only whats wrong, You need to put a meter on your o2 sensor, make sure its operating correctly, The coolant sensor would be next to check, I've been told by techs that a coolant temp sensor will cause a smog failure more often than an 02 sensor, also ck your fuel pressure regulator, The cat always gets blamed, my car failed miserably last time, 1 small vacuum leak and the coolant temp sensor (completely inoperable) and a slow o2 caused the fail. Colorado has as tough a smog as Calif. running the cars on a dyno through a simulated drive. The cat on my 91 318i is the original.

Again, my cat is not OEM, and I no longer have the stock exhaust. That is why I am asking what cat to buy. It's a cheap aftermarket "catco" that is over 6 years old, and from what I've read, they don't last that long, so It seems like a given to replace.

Knowing everything I've done, it can only be 3 things. My a/f ratio is off (couldn't you tell other ways? Bad idle? Bad fuel economy?) Or I have a leak in the intake (It has a new intake gasket). Or the CAT is bad. I doubt a failing O2 or coolant sensor would cause such high numbers in all 3 tests. I have multiples of each sensor, I'll try them all if I have to.

I'm actually convinced it will pass with a new cat. All the parts on the engine are still basically new. Even if the car was slightly out of tune, I think with a new cat and a few adjustments it would pass. Lots of people online that failed on ALL test by high numbers passed after changing the cat.

[homegrone30]

Again, my cat is not OEM, and I no longer have the stock exhaust. That is why I am asking what cat to buy. It's a cheap aftermarket "catco" that is over 6 years old, and from what I've read, they don't last that long, so It seems like a given to replace.

Knowing everything I've done, it can only be 3 things. My a/f ratio is off (couldn't you tell other ways? Bad idle? Bad fuel economy?) Or I have a leak in the intake (It has a new intake gasket). Or the CAT is bad. I doubt a failing O2 or coolant sensor would cause such high numbers in all 3 tests. I have multiples of each sensor, I'll try them all if I have to.

I'm actually convinced it will pass with a new cat. All the parts on the engine are still basically new. Even if the car was slightly out of tune, I think with a new cat and a few adjustments it would pass. Lots of people online that failed on ALL test by high numbers passed after changing the cat.

Your a retard. A cat wont fix a rich condition. Dont ask for advise if your convinced your already right.

[homegrone30]

What really sucks for you is those numbers pass in Texas

[schröe30er]

Im no smog tech but with number like those I would lean towards a tune up. Cats are supposed to be a lifetime part thats why they are illegal to remove. We all know 20 y/o cats probably need changed but that due to them being clogged by a motor that runs like shit. And yes oil can effect emmisions Ive seen it first hand. The gas mixes with oil especially if your running rich already. Im looking at your hc's, cats cant do anything with hc's. You are running rich because the computer is seeing a lean condition so it is dumping fuel to compesate. Do a tune up and check your afm, and tps. If youcan get them to do a test mode try and create a vacuum leak to compensate for the fuel.

I've been reading that a bad CAT causes high failed numbers in all three tests. That your car would have to be pretty out of tune to get those numbers. I would say if someone was getting numbers like that from a bad tune job on an OEM cat...either get rid of your mechanic, or sell your car and get a bike. This e30 spent it's whole life in Beverly Hills, dealer serviced. It's far from a beaten down vehicle. I've only made it better. Fat chance its out of tune that badly. It's only seen 500 miles since a full tune up before passing smog a year ago. What would cause it to go out of tune that much? Btw, I'm not claiming its perfectly in tune. I'm sure it isn't.

So the thing I read about the oil was correct, it does have an affect on emissions. Seriously why wouldn't it! This car sat for 6 moths, and I only drove it a couple days before I smogged it. I'm starting to think it's a mixture between a crappy cat that may be dieing, and not changing the oil after it's been sitting for 6 months.

"We all know 20 y/o cats probably need changed but that due to them being clogged by a motor that runs like shit."

Or a shitty non-oem cat simply failed as they do everyday. I did mention that I no longer have the OEM muffler and exhaust because of PO...

I get why many of you would think my car is out of tune, you guys keep thinking I have the OEM exhaust. I don't. These high numbers could EASILY be coming from the shitty catco CAT that's on there.

Here are two things that I have seen on the internet lately that supposedly clean the cat. First is to pour a gallon of lacquer thinner in the gas tank and drive the car hard for 150 mi. Second is to disconnect the cat and soak them in a bucket of soap water over night. I do not know if any of these methods works so do not quote me on these. Try them at your own risk.

I read that about the lacquer thinner, but only one place. That would be awesome if it actually worked.

[schröe30er]

Your a retard. A cat wont fix a rich condition. Dont ask for advise if your convinced your already right.

I don't think a CAT fixes anything, except maybe your health. But I am also not convinced that I'm running rich yet.

Btw, I didn't ask for advice on how to tune up a car. I've been working on cars for 15 years. If you go back and read. I was asking what the cheapest Cali-CAT I could buy was...

Retard.

[S62]

Someone has probably already said this but the things that will cause you to fail smog are airflow meter, o2 sensor, spark plugs and maybe a valve adjustment?? Make sure that the car is properly heated up so the cat is at is working at max efficency.

[schröe30er]

What really sucks for you is those numbers pass in Texas

I lived in north Austin for over a year, a couple years ago. Off Airport Bl and 46th. I would pay a thousand dollars for a smog test just to never live through your weather again haha. I have major love for Texas though, if it wasn't for the damn weather I could see myself living there.

For the whole time I was there I had access to a salvage yard with 6 untouched e30's, it was the shit! It was during cash for clunkers. If those cars were in cali, they would have been stripped before they reached the yard.

[homegrone30]

Well your title and question stated are a little contradictory. Cats are cheap if your in the buissness and if you were you wouldnt ask where to buy one. I got a 2.5 inch dual in dual out magnaflow cat for $77. But that was from a local exhaust parts distributor. I could get you the same deal but then I would have to ship. Too bad you left Austin.

[homegrone30]

Btw all I stated was a rich condition. I never said it was out of tune. In a perfect world with a motor that makes a perfect burn you would have no hc's at all. Hc= hydrocarbon or unburnt fuel. The reason why this fuel is not burning is because theres too much fuel being mixed in the cylinders. Thus causing a rich condition.

[schröe30er]

Well your title and question stated are a little contradictory. Cats are cheap if your in the buissness and if you were you wouldnt ask where to buy one. I got a 2.5 inch dual in dual out magnaflow cat for $77. But that was from a local exhaust parts distributor. I could get you the same deal but then I would have to ship. Too bad you left Austin.

Yea my title may have been a little confusing, I'll give you that. I thought everything I said otherwise was fairly clear. I tried to be as detailed as possible. My "confusing" noob question may have led some to believe I was a full time noob as well. So they offered some very good extra advice, mighty admirable. As oppose to people saying...why don't you search! I don't want people to think I can't search. And at the same time I didn't want to sound discourteous either. I appreciate all the advice from anyone regardless of whether I know it already, sometimes I don't. Someone else will find this thread and find it useful one day too. I admitted I was a noob when it came to CATS.

Yea, I don't really have an exhaust/cat connection, I'm not "in the business" so to speak. And I'm only a pro mechanic in my mind. I've done some bolt-ons before. But I've never had to replace just the cat in 15 years. Maybe cause no rust here? If they're suppose to last for life, I'd imagine only rust would make someone need to buy a new one.

I never asked where to buy one, I've already found some, I posted links. It's when I search "by size" using summit or google, they say they're made for different cars. That's throwing me off. I cant find a 2.5in Cali-Cat made for a bmw. I was asking if I could use them anyway. Are they the same internally? I cant use magnaflows website since they only offer Model/Year search now. It is now illegal in Cali for them to sell you a cat based on engine size, car weight and pipe diameter. I would use their site to cross check part numbers then search for the best price, but I can't.

From magnaflows website..

ALL California vehicles will no longer be based upon G.V.W. (Gross Vehicle Weight) and engine size. The Application look-ups below are the ONLY approved method for determining the correct part number for ALL California Vehicles. It is illegal in California to select a catalytic converter for installation based solely on vehicle weight, engine size, physical shape, size, configuration or pipe diameter.

Since my exhaust is completely different now, I cant use the vehicle look-up. Using that the closest I can get to a cat I could use is the Eta cat. I don't want an Eta CAT.

[schröe30er]

Btw all I stated was a rich condition. I never said it was out of tune. In a perfect world with a motor that makes a perfect burn you would have no hc's at all. Hc= hydrocarbon or unburnt fuel. The reason why this fuel is not burning is because theres too much fuel being mixed in the cylinders. Thus causing a rich condition.

Totally man, I got you...hakuna matata.

[homegrone30]

Salud!