So I just went to smog…FAILED, Advice?

[AndrewBird]

$61:

http://www.summitracing.com/parts/CTO-6906R/

And your oil won't change your emissions. That is, unless you are burning oil, but then it wouldn't matter if it was fresh or not.

[bernzpeed]

Crc!!!

[schröe30er]

$61:

http://www.summitracing.com/parts/CTO-6906R/

And your oil won't change your emissions. That is, unless you are burning oil, but then it wouldn't matter if it was fresh or not.

Ok, I had read something about changing the oil beforehand if its been sitting. It's not even dirty though, so forget it. Unfortunately that cat is 49 state, I'm in Cali. Summit can't even ship it here.

Crc!!!

For $11, why not right? Maybe I will just try that and get a decent cat in a couple months.

[schröe30er]

I'm finding it hard to find one. Many places make me go by car
year/model, but its been changed to 2.5in single pipe. Basically
I'm looking for one about the size of an eta cat right?

[schröe30er]

Am I blind? What's the difference between these cats? Besides one being 2.5 inches in/out..

http://www.magnaflow.com/02catalytic_converters/02product/displayuniversal01.asp?catalogid=45886&universal=36005

and

http://www.magnaflow.com/02catalytic_converters/02product/displayuniversal.asp?universal=34006

There's a $100 difference in price. They both say "vehicle specific", but
they're talking about dimensions right? Aren't they the same internally?
Regardless of model of car?

Edit:
It says The 34006 is a "slip fit" on summitracing. What's the difference?

Edit 2:
I'm an idiot, I guess there all "slip fit".

[KenC]

An exhaust shop will weld one in for next to nothing.

[schröe30er]

An exhaust shop will weld one in for next to nothing.

Ok, I fixed my previous post, It did sound like I didn't know how a cat was installed haha. I was just wondering specifically about the "slip fit" type cat. I previously read it has slightly different flanges, but I understand now there all slip fit.

This 34006 cat is only $65, Where as the Eta cat is $160, and they're both basically identical "externally" and Cali CARB compliant...blah blah. Btw, I'm only comparing to an Eta cat since I have a single pipe exhaust on my 325i. I'm assuming it will be similar in dimensions to the one I'll need to get.

So I only have the one question,

Will that Magnaflow 34006 cat I linked too work. Is it the same internally, regardless of whether its for a different car?

It will probably cost $45-$50 in L.A., to have a shop weld it on. Same as a muffler. So not quite next to nothing, not for me right now anyway.

[edocm]

Pass Smog

I have to agree with Bernzspeed. Try CRC...can be bought at auto parts stores for about $12~$15.
Prior to testing I adjusted the valves, oil change and new plugs and then added CRC to 3/4 a tank of gas then stopped by the smog shop to let them know I'd be back in about an hour.
Got on the freeway and drove my car a bit hard staying in 4th mostly to keep the revs up and down (goosing it once in awhile to not keep a constant speed and help burn off carbon) for about an hour. Got off the hwy and went back to the shop to get smoged, NOT shutting off the engine to keep it hot while waiting for the tech to pull it into the shop and hook it up to test. The numbers were amazingly low. Better than a new car.

[jlevie]

Your catalytic converter could be bad and a be problem, but if the engine and management system is operating properly the car should be able to pass, or come darn close to passing, emissions testing with no catalytic converter. The first thing I'd do would be to make sure that the engine is running right.

[schröe30er]

I have to agree with Bernzspeed. Try CRC...can be bought at auto parts stores for about $12~$15.
Prior to testing I adjusted the valves, oil change and new plugs and then added CRC to 3/4 a tank of gas then stopped by the smog shop to let them know I'd be back in about an hour.
Got on the freeway and drove my car a bit hard staying in 4th mostly to keep the revs up and down (goosing it once in awhile to not keep a constant speed and help burn off carbon) for about an hour. Got off the hwy and went back to the shop to get smoged, NOT shutting off the engine to keep it hot while waiting for the tech to pull it into the shop and hook it up to test. The numbers were amazingly low. Better than a new car.

I still may try that stuff if I can't find a cat for under $100. I'd rather pass without a mask. I'm convinced i still need a cat. Its a cheap aftermarket cat and its 6 years old. I dont even think its a Cali cat, PO spent 3 years in chacago. He changed it before the new laws in 2009.

Your catalytic converter could be bad and a be problem, but if the engine and management system is operating properly the car should be able to pass, or come darn close to passing, emissions testing with no catalytic converter. The first thing I'd do would be to make sure that the engine is running right.

Should come close to passing w/out a cat? That has me concerned. Is this true? Cali smog is pretty strict. Everything has been replaced on the engine, including Rebult head, Gaskets, belts. New muffler. I passed smog once after, and put maybe 1k miles on everything since. Wouldn't it be throwing codes?

[jlevie]

Should come close to passing w/out a cat? That has me concerned. Is this true? Cali smog is pretty strict. Everything has been replaced on the engine, including Rebult head, Gaskets, belts. New muffler. I passed smog once after, and put maybe 1k miles on everything since. Wouldn't it be throwing codes?

Understand that you have 20ish year old sensors and the like in the engine management system. And even after all that engine work you could have intake leaks.

My actions would be to:

1) Have a smoke test run to check for intake leaks
2) Do a leak down test to check for blowby bast the rings
3) Replace the O2 sensor with an OE part
4) Check rail fuel pressure
5) Have the injectors cleaned, rebuilt, and flow tested
6) Replace the ignition wires, distributor cap, and rotor
7) Verify the operation of the ECT, and AFM
8) Verify proper operation of the cooling system by direct measurement of head temperature.
9) Run the car on a dyno with a wide band O2 sensor and see what the A/F ratio is at during part & full throttle operation.

Depending on what the A/F ratio looks like in (9) and where it is off, will determine where to go next. That could include replacement of the DME or engine harness.

The engine management system has to be pretty far off nominal before any codes are thrown. You'll fail on emissions long before you'll get a code.

[schröe30er]

Understand that you have 20ish year old sensors and the like in the engine management system. And even after all that engine work you could have intake leaks.

My actions would be to:

1) Have a smoke test run to check for intake leaks
2) Do a leak down test to check for blowby bast the rings
3) Replace the O2 sensor with an OE part
4) Check rail fuel pressure
5) Have the injectors cleaned, rebuilt, and flow tested
6) Replace the ignition wires, distributor cap, and rotor
7) Verify the operation of the ECT, and AFM
8) Verify proper operation of the cooling system by direct measurement of head temperature.
9) Run the car on a dyno with a wide band O2 sensor and see what the A/F ratio is at during part & full throttle operation.

Depending on what the A/F ratio looks like in (9) and where it is off, will determine where to go next. That could include replacement of the DME or engine harness.

The engine management system has to be pretty far off nominal before any codes are thrown. You'll fail on emissions long before you'll get a code.

I totally understand, I've restored enough older cars. I'm not one of those guys...I swear haha.:up:

So I did half of that list less than 1k ago. It has an OE 02 sensor. I normally don't buy aftermarket parts unless they're made in Germany. Or by a reputable company. CAT being the exception this time.

Leak down test was performed after the new head, and it's fine. I haven't messed with the A/F system much since I got the car. It's the next area I need to check out. System seems to be running fine. I'll be cleaning the AFM sensor anyway, so Ill check all other relatives then.

The car was sitting for 4 or 5 months recently.

I was planning on getting a wideband 02 sensor gauge soon, like this year, I just don't have the coin right now. Others seem to have physical symptoms arise when the DME is going. I have zero problems, this car runs purrfectly. Idle, acceleration, WOT, MPG. I have an extra 173 DME just in case.

But if it's true that in California, an e30 should come close to passing, even without a cat, well now I am second guessing everything...

Thanks for your assistance jlevie, I do appreciate it.

[oldmann]

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.

[homegrone30]

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.

[dnguyen1963]

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.