BMW E39 Smog Survey

BMWdiy.INFO
E39 Smog Survey

Prepared by VietSB
Thanks to everyone who contributes their data
Modified 07.29.06

NOTE: Use this information at your own risk. All data listed here is unverified and hearsay, so use it as a rough estimate rather than as a true guide. This information is provided for entertainment purposes only!

BACKGROUND: Some non-VANOS (1997-1998) 540i E39's are having difficulties passing the new California "Enhanced" Smog Check II system which uses rollers like a dyno, plugs into the OBDII port, checks for fuel cap leaks, etc. Although I'm unsure as to what the root causes might be, I can report that my smog check mechanic noted the exact same thing and specifically with late-model BMW's. The culprit seems to be the new "NO" or "NOx" test for Nitrogen, measured in parts per million (PPM). As you can see below, the measurements vary greatly on non-VANOS cars. When more VANOS data is collected, we'll see if there's any real correlation.
This survey and information contained within deals primarily with California-related smog issues and advice, but might benefit others as well.
A few notes and tips:

Try to have your catalytic converter as hot as possible prior to beginning the test. Letting your cats cool lowers their efficiency, thereby increasing your NO (PPM) output.
Federal law mandates that emissions-related systems such as the OEM catalytic converters be covered for 8yrs/80K mi. If you fail smog using your OEM cats, it's worth seeing if the dealer will replace them within this warranty period.
In California, all emissions-related systems on your car must be CARB-certified. That means even minor mods such as Cold Air Intakes might raise an eyebrow during the visual inspection phase. Some other mods that might be questioned? Mufflers, aftermarket cats, custom headers, forced induction devices, etc.
Cats loose their efficiency as they age. I had what sounded like loose metal parts in one of my cats so the dealer replaced it under CPO. If you hear the same, it's best to get it inspected.
"Tether" reported the following on Roadfly.com, "The NOx is normally higher when the combustion temps are higher in the cylinder. This is normally caused by advanced timing, which is normally attributed to a modified or damaged O2 sensor or also a bad catalytic converter. I would have your cats checked out."
"Jim Cash" wrote the following on Roadfly.com, "The Nitrogen Oxide emissions come from running a lean burn engine. This is good in that it lowers CO emissions but can cause the NO issue in the higher temperatures of a lean mixture operation. The Cats are there to clean up the NO issue - so you may be dealing with an aging cat. When going for an emissions test it is best to do a good run (10-15 miles) and during that time do some heavy acceleration if possible. Doing some "booting under load" just before you pull in for your test will also help heat up the cats (lots of snap-crackle-pop sounds when you shut off."
Possible fixes that have been suggested so far are running fuel injector cleaner or CRC Guaranteed To Pass� Emissions Test Formula, replacing the O2 sensors, replacing the cat, checking/replacing the valve cover gasket, and replacing the PVC valve.
Please e-mail me your smog results regardless of passing or failing so failure trends and repairs can be identified. Be sure to submit info as formatted below with year, model, mileage, test date, emissions-related mods, etc listed.

E39 Smog Survey

Enhanced Smog Check (aka Smog Check II)
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
VietSB (1997 540iA 57K mi - CA - 01.14.04 - SuperSprint muffler, minor engine
and software mods)
15mph 1447 14.7 0.2 49 9 1 0.47 0.02 0.02 409 57 398 PASS
25mph 1455 14.7 0.1 33 7 1 0.44 0.03 0.01 696 50 261 PASS
TedT (1998 540i/6 100K mi - CA - 04.01.04)
15mph 1486 15.4 0.0 49 9 3 0.47 0.02 0.00 409 57 929 FAIL
25mph 1535 15.2 0.1 33 7 1 0.44 0.03 0.00 696 50 452 PASS
TedT - (1998 540i/6 100K mi - CA - 04.27.04 - Replaced pre-cat O2 sensors)
15mph 1523 15.2 0.0 49 9 4 0.47 0.02 0.00 409 57 3 PASS
25mph 1559 15.1 0.0 33 7 3 0.44 0.03 0.00 696 50 0 PASS
LouisM (1999 540i/6 69.5K mi - CA - 05.04 - Spark plugs changed 5K mi ago)
15mph 1461 15.00 0.07 49 9 1 0.47 0.02 0.01 409 57 35 PASS
25mph 1645 14.97 0.05 33 7 1 0.44 0.03 0.01 696 50 32 PASS
LouisM (1999 540i/6 89.0K mi - CA - 06.06 - Replaced MAF sensor and pre-cat sensors due to error codes.)
15mph 1454 14.20 0.02 49 9 0 0.47 0.02 0.08 409 57 337 PASS
25mph 1602 14.02 0.02 33 7 0 0.44 0.03 0.08 696 50 344 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
MikeS (1998 540iA 85K mi - CA - 05.06.05 - Stock)
15mph 1613 15.5 0.0 49 9 0 0.47 0.02 0.01 409 57 760 FAIL
25mph 1488 15.4 0.0 33 7 0 0.44 0.03 0.00 696 50 751 FAIL
MikeS (1998 540iA 85K mi - CA - 05.06.05 - Replaced both catalytic converters and pre-cat O2 sensors.)
15mph 1606 14.6 0.3 49 9 26 0.47 0.02 0.02 409 57 21 PASS
25mph 2263 14.7 0.1 33 7 12 0.44 0.03 0.01 696 50 206 PASS
Tyrone (1997 540i/6 101K mi - CA - 03.30.04 - Dinan software/BB Triflo muffler)
15mph 1523 15.0 0.8 49 9 23 0.47 0.02 0.04 409 57 404 PASS
25mph 1564 14.4 1.0 33 7 16 0.44 0.03 0.01 696 50 497 PASS
Tin (1997 540iA 71.5K mi - CA - 02.05)
15mph 1630 14.5 0.03 49 9 11 0.47 0.02 0.02 409 57 204 PASS
25mph 1671 14.5 0.05 33 7 5 0.44 0.03 0.01 696 50 435 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
jake_sf (1997 540i/6 - CA - 2004)
15mph 49 9 0.47 0.02 409 57 874 FAIL
25mph 33 7 0.44 0.03 696 50
clymberz (1998 540iA - CA - 03.01.04 - Later replaced valve cover gaskets
and PVC valve to pass)
15mph 1564 14.9 0.03 49 9 3 0.47 0.02 0.01 409 57 656 FAIL
25mph 1416 14.9 0.03 33 7 1 0.44 0.03 0.01 696 50 558 PASS
erik (1998 540i/6 68.8K mi - CA - 06.01.04 - All original emissions equipment)
15mph 1408 15.02 0.00 49 9 0 0.47 0.02 0.03 409 57 248 PASS
25mph 2383 15.00 0.02 33 7 5 0.44 0.03 0.01 696 50 509 PASS
fmora (1999 540iA 70K mi - CA - 07.07.04 - Fixed intake manifold vacumn
leak & replaced Mass Airflow Sensor 1 year ago)
15mph 1754 15.20 0.0 49 9 2 0.47 0.02 0.00 409 57 1 PASS
25mph 1893 15.10 0.00 33 7 4 0.44 0.03 0.00 696 50 7 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
(540i - 12.28.02)
15mph 14.4 0.7 34 0.12 767 PASS
25mph 14.5 0.4 17 0.03 552 PASS
(540i - 07.09.04 - Relaced O2 Sensors)
15mph 13.8 0.8 3 0.00 5 PASS
25mph 14.1 0.3 2 0.01 32 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
Mike A (1997 540i/6 - VA - 2003)
15mph 71 11 0.39 0.03 553 184 PASS
25mph 68 35 0.38 0.09 501 250 PASS
Jim Cash (1997 540iA - Canada - 2004)
~25mph 31 0.01 269 PASS

Original Smog Check
%CO2 %O2 HC (PPM) CO (%)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS Results
VietSB (1997 540iA 52K mi - CA - 01.22.04 - SuperSprint muffler, minor engine
and software mods)
Low Speed 570 15.8 0.2 100 17 18 1.00 0.00 0.02 PASS
High Speed 2541 15.5 0.2 130 12 7 1.00 0.10 0.01 PASS

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