legacycentral bbs

Hello all...Just joined the forum 10 minutes ago. I know these are great sources on info. Used to be a member of Teamswift (sold the car), and am now driving a '92 Legacy Turbo w/automatic. Would have preferred a manual, but there you go. Anyway, I've put a ton of work into the car ( it was really let go ), And I have only one problem left...we have to pass an emissions test here in BC, and for the life of me, I can't get this thing through. It fails on driving CO. I'm allowed 9.3 g/km, and the best I get is 12.5. NOx and HC are fine. I've been through every sensor, scoped the temp sensor, replaced the o2 w/bosch unit, cleaned the maf, tested the cat, and it's all good. I've checked the test history, and it has a problem w/CO failures, but when it passes, it does so with flying colors, like 3.5 or something. This post may seem long winded, but I'm out of ideas. I've spent hours and $$$ trying to figure this out. Please help!

Before going for the test, drive the car VERY hard to get the converter hot. May only need to do this to pass. Is it a stock CAT though? My car passed with flying colours. Both my cars. My 93 legacy with 330,000km+ original motor never rebuilt or anything shows like 30ppm. My 94 legacy turbo, shows 9ppm. They only do a idle test here though. Both cars are stock btw.

I was told the same thing. Go for a long highway drive, get the converter HOT so it burns all the crap better.

I also heard a fresh oil change and higher octane gas helps

I don't know if the cat is OEM, but I did a pre and post test and it sniffs good. I tried the hot cat thing, but it almost seems like it has worse emissions when hot...like the PCM can't control things. I always run Chevron 92 octane. My cammed-out Swift wouldn't run on anything else.

It's your oxygen sensor.

O2 is brand new Bosch unit. But I heard that OEM has rhodium coating or something that makes them different. Is this true, or just a reason for the Dealer to charge $300?

So the numbers you posted was after you installed everything or before...... If before, have you gotten it tested again? I don't know anything special about the O2 sensor. I've got a Bosch Universal also but I don't have to do the emission testing.

All posted numbers are after repairs. The test was on Apr 7. If I can't sort this out, I won't be able to register the car this summer, and may have to sell it.

I am still thinking the CAT. If the exhaust is not all original then something was modified. Does not take much to make these cars pass emissions. There is two CAT's remember!

ericem wrote:I am still thinking the CAT. If the exhaust is not all original then something was modified. Does not take much to make these cars pass emissions. There is two CAT's remember!

Even if the cats are still there. They can be chemically dead. It's like pouring vinegar on baking soda. After a while it won't bubble any more.

Any who, what all exactly did you replace?

And when are you failing? On the idle test or the load test?

Lol I'd buy another cat and have an exhaust shop weld it in after the other two, then go take it for emissions.

asc_up wrote:Lol I'd buy another cat and have an exhaust shop weld it in after the other two, then go take it for emissions.

That is completely pointless "the reason is that the cat will be to far back to warm up". Might as well have the second cat cut out then replaced with a universal. But with thedanno luck, the first cat is prolly the dead one.

Skruyd wrote:

asc_up wrote:Lol I'd buy another cat and have an exhaust shop weld it in after the other two, then go take it for emissions.

That is completely pointless "the reason is that the cat will be to far back to warm up". Might as well have the second cat cut out then replaced with a universal. But with thedanno luck, the first cat is prolly the dead one.

It was a joke, hence the "Lol" placed before the sentence.

asc_up wrote:

Skruyd wrote:

asc_up wrote:Lol I'd buy another cat and have an exhaust shop weld it in after the other two, then go take it for emissions.

That is completely pointless "the reason is that the cat will be to far back to warm up". Might as well have the second cat cut out then replaced with a universal. But with thedanno luck, the first cat is prolly the dead one.

It was a joke, hence the "Lol" placed before the sentence.

Sorry, You just sounded monotone

Or you could remove the cats and try again. My turbo-swapped L passed w/o cats here in Wa.

Considering you never told me what part of the emissions you didn't passed, or you are just busy and I'll forgive you . Here is a lot of things to check. And yes, some of this stuff pertains to carburetor engines so ignore that stuff


ACCELERATION EMISSIONS
During acceleration, the engine momentarily drops out of closed loop and receives a richer fuel mixture for more power. During this time (depending on the system), the MAP or Airflow Sensor and the TPS sensor play critical roles in controlling the fuel mixture.

Most fuel-injected engines have either a throttle position sensor or switch that indicates when the engine is at idle. When this device indicates that the engine is no longer at idle, the on time of the injectors is increased to temporarily richen the fuel mixture. The same thing happens any time the engine comes under load and manifold vacuum drops. The MAP sensor tells the computer the engine is under load, and the computer responds by adding more fuel.

It is normal to see some spikes in CO during acceleration, but unusually high CO readings indicates that the fuel mixture is too rich. Possible causes might include:

Flooded charcoal canister or a leaky purge valve;

Leaky power valve (older carbureted engines);

Defective mass airflow (MAF) sensor, manifold absolute pressure (MAP) sensor, or vane airflow meter (VAF); or

Defective throttle position sensor.

If the feedback fuel control system is working properly and there are no apparent sensor or purge valve problems, the catalytic converter may be contaminated or not functioning.


CRUISE EMISSIONS
At cruise, the engine is lightly loaded and running at high rpm. Under these conditions, HC and CO should be low if the oxygen sensor and feed back control system are working properly, and the catalytic converter is in good condition.

High CO readings during cruise indicate a rich fuel condition. Causes here may include:

Defective O2 sensor;

Exhaust leaks upstream of the O2 sensor (check manifold gaskets and air plumbing connections);

Defective AIR pump or diverter valve (also loose or damaged air pump plumbing);

Defective MAP, MAF or VAF sensor;

Float level and operation (older carbureted engines); and

Power valve operation (older carbureted engines).