CA SMOG test failure and unexpected results...HELP :(

[TedSlick]

Hi guys...SMOG cops have me over a barrel.
The car is '85 Carrera, 100% stock. The engine was out (for oil leak fixes) for several months, but due to health related delays, we just got around to reinstalling. Didn't change anything except for new seals and gaskets, all oil related. Strange thing is it passed no problem in '02, only a few thousands odom. miles ago. I'm thinking something was not reconnected right.

Thought I would post the results and maybe someone could give me an idea where to start looking for a solution. A hose or wire connection? Maybe something obvious? The tech said "looks to be running rich". The CO results shot way up somehow.

TOP pic is the FAIL result ('04)
BOTTOM pic is the PASS result ('02)





Any ideas what I should look at first?

UPDATE EDIT: Latest pass results after installing new oxygen sensor:

[Emission]

Ouch - I feel your pain (see my thread).

Did you warm it up really well?

[TedSlick]

I drove it for about 20 min. beforehand, but it did sit for 15 min. in their line. I guess I wasn't too concerned since it has not had a problem with SMOG checks until now.

It's WAY out of range suddenly for CO.

[Emission]

Identical to my issue. Passed fine in 2002... but failed CO yesterday and today.

[TedSlick]

Yeah, Emission, I read your thread and some others before posting mine. Really sucks when the tech shakes his head, signalling the car failed

Check out how far off my CO is this time compared to last time. Your's is not far off the allowable.

I'll be reading up on how to change the 02 sensor. Or maybe go out and have it done. Would be nice to hear some consensus whether it seems to be the most obvious problem ...before doing the expensive hit-or-miss thing.

[stlrj]

Has your head temp sensor been updated or is it still the one wire type.

Cheers,

Joe

[TedSlick]

Not sure, but I would think it is whatever comes stock with the car for that year/model ('85).

[banjomike]

Your catalyst could be going bad. The difference in the two tests in the CO measurement is really huge. From the HC #s you definately won't get any benefit from leaning out the mixture because the HC will go up. Did they tell you what "Gross Polluter" means? are there extra requirements for you now?

Also one final question. Did you get sent to a test only station? Is there anyone with a 911 in california that hasn't been sent to test only station this year? I have a sneaking feeling that I'm always going to get sent to one.

[TedSlick]

Yep, I'm pretty sure you will only get sent to 'Test Only' stations from now on. All 3 of my cars ('91 and older) get sent there every time now (every two years).

'Gross polluter' only means the allowable is exceeded by (I think) 2X or more. I don't think it comes with any other ramifications.

Thanks for the reply.

[johnsjmc]

I agree that the O2 sensor is the likely candidate. I think the 84 may be a heated type (3 wire) . A shop can check the supply voltage to the heater as well as the output from the sensor itself or you can just change it (good idea if more than 80000 mi on it anyway)

[Wayne 962]

Something's wrong. If it were only the mixture, then the HCs might not been so high. It is indeed running extremely rich. I agree with the others, the first thing to replace is the O2 sensor...

-Wayne

[thabaer]

Inadvertently whacked the mixture towards rich, thermostat not letting temps stay up.

Or... air pump not connected or functioning and no oxygen getting fed to the cat to let it work.

[JBO]

Same thing happened this year with my BMW. Passed every year with "flying colors" as the tech would always say. Failed bad this year, which shocked me. Put in new O2 sensor and back to passing with flying colors! They are not too expensive either, so I hope that's all you need.

[TedSlick]

Thanks for the helpful posts to consider.

I've been looking at smog test results posted by others. Especially the O2% column. I noticed at the two different test speeds (15mph/25mph), the reading typically varies, as one might expect. On mine, the number is very low 0.1 and exactly the same at both speeds

'thabaer' mentioned the air pump not providing oxygen as required. Where is this in the system?

[TedSlick]

Reading Bentley manual (240-23), there is a diagram of the )2 Sensor. One surface is exposed to exhaust gases (the part that goes inside the CAT) and the other is open to the atmosphere where it allows air into the sensor.

My questions, could this have become clogged with engine cleaners, etc. when the engine was out of the car, causing incorrect operation? Also, wouldn't it be better to NOT have a protective heat shield around this "intake" end of the sensor if it is supposed to permit air into the system? Or is the shield absolutely necessary?

Just trying to figure thru the problem...

[johnsjmc]

The Carrera doesn't use an air pump system and doesn't have adjustable CO setting either. Some silicones sealers can confuse an O2 sensor hence the" sensor safe" sealants .The backside open to air and the shield is probably for cooling or shedding road splash. Stop fretting check the wiring to be sure it's connected and then try a new sender.

[TedSlick]

Update:

New aftermarket "universal" O2 sensor did the trick! Cost DIY about $50. Took me about 30 min. to install and do the 3-wire splicing.

The re-test cost $5 because CA DMV charges the smog stations a connection fee each time they tap into the database.

Thanks for all the great help and suggestions!

I'll post the latest (PASS ) results in the first post in this thread alongside the others.

[thabaer]

Originally posted by TedSlick
'thabaer' mentioned the air pump not providing oxygen as required. Where is this in the system?

nahh, ignore that dummy!

obviously zoned out and forgot the patient was Carrera/DME instead of a '79 RoW (no cat, no OXS, but WITH air pump )

congrats on the fix, gotta love those generic sensors at $100 less than the "proper"one.

[TedSlick]

Originally posted by thabaer
...gotta love those generic sensors at $100 less than the "proper"one.

The "proper" one (Bosch), as you say, was quoted anywhere from $169 to $250. The generic (Walker) was ~$50, available nearby.

BTW, the smog shop owner was very curious about the brand and cost after seeing how it performed. His smog station is a couple blocks from a Porsche shop that gives him lots of 911 business. Wanted to know so he could mention it to others.

He also inspected the sensor installation and said it looked "professional"...LOL. Hardly...I have no electronic background, just followed the directions and the Bentley manual. Used a heat gun to shrink wrap the connections. Presto!

[thabaer]

I assumed it was also a Bosch. I don't have OXS on my 911, but my quattros get a generic Bosch part for $40 instead of the same one with the "right" connector for $160.

Shrink wrap and heat guns... hoo-boy was I a happy camper when I found out I could buy that stuff retail (long ago in a galaxy..)