kel

Hi Gang,
I have been through Emissions Hell this year in Colorado. Never before had an RX fail, but they keep failing mine - 3rd time today (at $25 a pop).
Anyway, here's what's new:

Exhaust - turbo back by Rotary Specialists in Denver, with new cat
New Air filter
New o2 sensor

Checked all the adjustments - TPS, variable resistor etc

Today, I even ran the tank down to almost empty and put in 2 gals of e85 gas.
with the new O2 sensor, it cut the HC down by 2/3, but still .15 of a point too high.
Also, the CO is 5 points high - 25 when needs to be less than 20.

I think these f#$%ers are trying to fail it - they ran the test 4 times with two different technicians. I watched the display while the last test was going and the technician made the guide cursor blink red 7 times - that alone it seems would cause the HC reading.

Vent done, here's my question. What brand O2 sensor do you use? I put in a Bosch universal (only one I could find in stock), but my repair shop says Bosch won't work properly. He suggested I get a Mazda ($200) one, but I don't want to spend a double C after all the other costs already over budget. Suggestions?

Thanks a million

- k -

Icemark

So HC and CO is too high???



Kinda rare that just those too are too high.

But yes the universal Bosch XXX27 is fine, and usually under $30

kel

Thanks, Icemark
Yeah, HC & CO. NOx pass level is 6.0 and my car is at 0.46

I saw this chart, but it isn't very helpful about how to improve the mixture/air injection.

If this O2 sensor is adequate, I'm out of ideas of what to do. my mechanic thinks that the problem is how the technician is 'driving' it on the Dynamo

Icemark

well, thet chart is very easy to read.

If you are failing on high HC and high CO, then either you A/F mixture is off or the air pump is not injecting air into the cat.

Pretty simple. Only can be one of those two things. I'd check the air pump first and make sure the ACV is working correctly. If they are, then you just need to crank down the mixture (found right on the passengers shock tower underhood. DON'T adjust the A/F mixture before checking the air pump and ACV first.

And it is not the tech driving it on the dynamo... you need to find a new mechanic. Anyone driving the car under any conditions should have the car pass if everything in the emissions system is working. Your mechanic is an idiot for even suggesting that.

Bob Boberson

iTrader: (3)

I just failed emissions today, only the HC though. What does "run-in converter" mean? I got a little over twice of what is allowed on both tests.

Icemark

The converter is broken up or failing or melted in the first stage (monolithic cat converters like our cars use are really two stages).

Or your dumping a lot of fuel down the pipes

Or your pre-cat may have failed and started filling the main cat

kel

Thanks millions for the insight. I took the ACV off (i'm sure the air pump is blowing fine). and tested it like Hailers had recommended in earlier threads. Found that the switching diaphram was completely vulcanized. Crumbled into pieces when I removed the valve.
Anyway, I can't find a replacement ACV, so I'm putting a good diaphram from a n/a ACV into my turbo one.

I believe you're right. the last test was much closer - since replacing the o2 sensor, and it make sense that this problem would be the last thing.

Thanks again for your insight. Sorry for the cliche, but you ARE the man!

- k -

Icemark

To pass smog without a ACV, just run the output from the air pump directly to the cat, bypassing the ACV.

That should dump enough air into the cat to pass