Smog Check

[Tyler]

I just got my CA smog test done, and although she passed, it was too close for comfort.

Hydrocarbons at 15mph: 49 vs average of 4 and max allowed of 50.
Hydrocarbons at 25mph: 33 vs average of 4 and max allowed of 34.

Seems really high to me, but I don't have access to my files to see what the numbers were two years ago from the same shop. Does anyone else have some comparable numbers? '01 car with 11k miles; test done in Santa Monica at the Pico/Cloverfield station.

Thanks in advance,

Tyler

[macfly]

This is cerainly a worry, but I have no information on these figures from anyone as yet - I would suggest that from now on we all post the emission test results here to get a better idea of the output of our engines.

[Norcal]

Mine is coming up this month, I'll post it.

[SProZ8]

Test done at Irvine BMW, 2/7/07 with 17,000 miles
15 mph, %CO2-15.3, HC-15, CO-.02, NO-13
25 mph, %CO2-15.4, HC-8, CO-.03, NO-16
All are about average but the Hydrocarbons are higher than the 4 average.
good luck

Steve

[thegunguy]

Mine is coming up this month, I'll post it.

This raises a interesting offline question....:D

[Norcal]

This raises a interesting offline question....:D

I should be gettinng mine checked by the end of the month I hope.

[thegunguy]

That's great to hear!

[Tyler]

Thanks. Any thoughts on what could be the problem? Clearly its not burning fuel efficiently. Quick guesses would be MAF or O2 sensors, but the check engine light is not on.

Tyler

[DanaC]

I just tested one in our shop and the results are:
HC
15mph - 13
25mph - 9

Was the car fully warm? If it was not that could be the problem. I would have it checked to see if any faults are logged. There are many things it could be and to guess from afar would not be a good thing to do. I would check for faults though and depending on the outcome, start looking for air leaks on the intake side (gaskets, etc) It could be an oxygen sensor acting up as well although that should illuminate the check engine light.

Good luck,
Dana Caldwell
Service & Parts Director
Peter Pan BMW

[FWK-Z8]

Thankfully, I don't live where they have to do the dyno test. I just had myZ8 checked at idle and 2500 RPM. It tested amazingly clean

.....................CO2 ................HC(ppm).................... CO(%)............
..................................MAX... AVE... MEAS .....MAX...... AVE.... MEAS
IDLE ..........14.70%...... 100... 17 .........7........ 1.00...... 0.00..... 0.03
2500 RPM ...14.50%...... 130... 12......... 7........ 1.00...... 0.10..... 0.02

[redz8]

2002 @ 16631 miles
Test performed at Sterling BMW, CA

15mph %CO2=15.8 %O2=0.0 HC=50 %CO=.02 NO=1
25mph %CO2=15.7 %O2=0.0 HC=34 %CO=.03 NO=1

Looks like the HC is at the upper bound. This worries me a bit. I wonder if this has anything to do with the carbon buildup issue.

[FWK-Z8]

Thankfully, I don't live where they have to do the dyno test. I just had my Z8 checked at idle and 2500 RPM. It tested amazingly clean

.....................CO2 ................HC(ppm).................... CO(%)............
..................................MAX... AVE... MEAS .....MAX...... AVE.... MEAS
IDLE ..........14.70%...... 100... 17 .........7........ 1.00...... 0.00..... 0.03
2500 RPM ...14.50%...... 130... 12......... 7........ 1.00...... 0.10..... 0.02

These are my numbers from earlier this year. I live in the Central Valley and thus have the less stringent tests.

I have heard others have problems with other BMWs. Unburned HC's is a strong function of engine and catalyst temperature. There are procedures in the test to make sure it is done on a warmed engine, and I know others who have had their cars fail because these weren't properly followed. I'd recommend taking your car for a nice 50 mile run before the test. Stay with the car and make sure it doesn't sit around all day before testing it.
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[redz8]

I spent some time on the M5 Forum and it seems like the HC is all over the place -- even for the same car tested back to back.

So I tend to agree with you that engine/cat temperature probably plays a big part. On the day of my test, the car sat at the service department for about 1 hour before it was taken in. The temperature on that day was in the upper 60s, so it makes sense that the engine may have cooled down substantially during the wait.

[thegunguy]

I find humor in the paradox of the California Car Culture vs. California Emission Tolerance.

[FWK-Z8]

Must be some land in Nevada for $50 you could put an old house trailer on to get some NV plates

[Z8doc]

This is cerainly a worry, but I have no information on these figures from anyone as yet - I would suggest that from now on we all post the emission test results here to get a better idea of the output of our engines.

Vanos problem noted on the earlier models of the Z8 be the problem? :confused:

[SProZ8]

The semi annual smog inspection hit once more and in lieu of the dealer performing the test, I took it into the local smog station where it failed on hydro carbon at 25 mph, 34 ppm allowed, 37 ppm measured. A retest was free, so with a bit of hard driving, the fun part, to get the cats up to temperature, the ability to drive right onto the test ramp, and the tester runing the rpm up to 2500 for a minute prior to the test to warm the cats, we were able to bring the HC measured down to 26. Passed. Still a substantial increase over 2 years ago. (See previous post). Dana Cadwell's post on getting the cat temperature up worked it's charm. Why? To quote a local BMW guru mechanic, Joe Schneider; "Just keep driving it until it gets worse, then we'll be able to determine the problem." That issue related to some drivetrain noise on my 2800CS, and he was hard of hearing.

[Tyler]

Back after two years for my next test. Car has about 14k miles now. This time, I instructed them to make sure the car is fully warmed up before the test.

Hydrocarbons at 15mph: 41 vs average of 4 and max allowed of 50.
Hydrocarbons at 25mph: 27 vs average of 4 and max allowed of 34.

Lower than before, but still seems high to me. I should note that this time I have fault codes for both Exhaust Cam Position Sensors, so I'll replace those next week along with the two Intake CPS' for good measure.

Tyler

[macfly]

Also maybe consider changing the MAF's as they tend to go off over time too, and can cause the car to run poorly.

[redz8]

My 2003 @ 197 miles went in for smog:

15mph %CO2=15.2 %O2=0.2 HC=0 %CO=.01 NO=0
25mph %CO2=15.1 %O2=0.0 HC=1 %CO=.04 NO=0

I don't know what to make of it, but the HC on these cars measures near the max, but in my case, it measured 0. Milage related? Chaos theory?

[Tyler]

2001 with 15,800 miles. HCs at max again. Perhaps not warmed up enough, but most likely chaos theory as suggested above. Car drives great with no codes.

15mph %CO2=15.3 %O2=0.0 HC=50 %CO=.02 NO=3
25mph %CO2=15.3 %O2=0.0 HC=34 %CO=.03 NO=4

[CraZ8's Johnny Q]

My 2002 w/17K miles failed

15 mph HC Max 50 Average 4 Measured 75
25 mph HC Max 34 Average 4 Measured 34

I took it back for a retest a couple weeks later. I warmed it up more this time. Results were much lower.

15 mph HC Max 50 Average 4 Measured 17
25 mph HC Max 34 Average 4 Measured 14

[macfly]

Yes, the cats have to be HOT to get thru smog tests.

[JohnAnthony]

Vanos problem noted on the earlier models of the Z8 be the problem? :confused:

VANOS is same for all production years, accumulator was the difference - and if you've had your vanos replaced likely you have updated solenoid boards and the accumulator retrofited

here's a failed CA smog - engine ran rich as a result of vanos consumables

http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/172747-failed-emissions-twist.html