BMW E30 Smog Survey

BMWdiy.INFO
E30 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 E30 325i's are having difficulties passing the new California "Enhanced" Smog Check II system which uses rollers like a dyno and includes checks for fuel cap leaks, etc. The primary culprit seems to be the new "NO" or "NOx" test for Nitrogen, measured in parts per million (PPM).
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.
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.
Possible fixes that have been suggested so far are running fuel injector cleaner or CRC Guaranteed To Pass� Emissions Test Formula, replacing the O2 sensor, replacing the cat, checking/replacing the valve cover gasket, top engine cleaning, and replacing the PVC valve.
I haven't read this completely, but it covers causes for smog failures. Here's the link for a Toyota Emission Analysis document from Autoshop101.
"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."
Based on my barely passing, the mechanic recommended a top engine cleaning and new (quality) catalytic converter if I run into issues next time.
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.
For reference purposes, in CA "GROSS POLLUTER" status occurs if any values are greater than:

HC (PPM) CO (%) NO (PPM)
15mph 288 2.23 1982
25mph 238 2.11 1782

E30 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 (1989 325i 142.5K mi - CA - 06.30.04 - Initial run, all original emissions equipment,
Dinan chip, SuperSprint cat back exhaust)
15mph 1836 14.80 0.20 108 31 83 0.71 0.10 0.28 767 237 959 FAIL
25mph 1867 15.00 0.00 83 20 16 0.58 0.09 0.04 706 199 133 PASS
VietSB (1989 325i 142.8K mi - CA - 07.10.04 - Replaced O2 sensor and ran CRC Guaranteed To Pass�
Emissions Test Formula, Dinan chip, SuperSprint cat back exhaust)
15mph 1852 14.90 0.20 108 31 67 0.71 0.10 0.30 767 237 754 PASS
25mph 1918 15.10 0.00 83 20 17 0.58 0.09 0.06 706 199 180 PASS
VietSB (1989 325i 152.5K mi - CA - 06.24.06 - New OEM O2 sensor and Bosch spark plugs,
oil change, removed Dinan chip, SuperSprint cat back exhaust)
15mph 1822 14.90 0.00 108 31 9 0.71 0.10 0.04 767 237 159 PASS
25mph 1926 14.90 0.00 83 20 7 0.58 0.09 0.02 706 199 84 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
GregC (1989 325i 155K mi - CA - 05.17.04 - Initial run, cat replaced a few years ago)
15mph 1644 14.20 0.47 108 31 186 0.71 0.10 0.60 767 237 1844 FAIL
25mph 1614 14.70 0.12 83 20 73 0.58 0.09 0.25 706 199 860 FAIL
GregC (1989 325i 157.5K mi - CA - 06.30.04 - Top engine cleaning and
replaced catalytic converter again)
15mph 1827 14.81 0.04 108 31 22 0.71 0.10 0.01 767 237 25 PASS
25mph 2033 14.87 0.02 83 20 16 0.58 0.09 0.03 706 199 3 PASS
GregC (1989 325i >179.3K mi - CA - 04.18.06 - Replaced O2 sensor,
oil change, 1yr old spark plugs/distributer cap/rotor)
15mph 14.80 0.20 108 31 106 0.71 0.10 0.24 767 237 508 PASS
25mph 14.90 0.10 83 20 48 0.58 0.09 0.11 706 199 208 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
DKSF (1988 325is 123.7K mi - CA - 05.03.04 - Initial run)
15mph 1658 14.67 0.20 114 31 115 0.73 0.10 0.52 785 237 965 FAIL
25mph 1825 14.85 0.10 88 20 84 0.61 0.09 0.29 724 199 488 PASS
DKSF (1988 325is 124.1K mi - CA - 05.10.04 - Replaced O2 sensor)
15mph 1669 14.93 0.20 114 31 96 0.73 0.10 0.24 785 237 839 FAIL
25mph 1830 15.08 0.09 88 20 60 0.61 0.09 0.13 724 199 316 PASS
DKSF (1988 325is 124.4K mi - CA - 05.14.04 - Ran 91 octane gas)
15mph 1664 14.80 0.10 114 31 62 0.73 0.10 0.22 785 237 654 PASS
25mph 1824 14.60 0.10 88 20 92 0.61 0.09 0.22 724 199 546 FAIL
DKSF (1988 325is 125.1K mi - CA - 06.11.04 - Ran CRC Guaranteed To Pass�
Emissions Test Formula)
15mph 1675 14.80 0.10 114 31 52 0.73 0.10 0.17 785 237 445 PASS
25mph 1861 14.80 0.10 88 20 62 0.61 0.09 0.16 724 199 375 PASS
CO2 %O2 HC (GPM) CO (GPM) NOx (GPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
ScottW (1989 325iC 175K mi - CA - 2004 - Initial run)
15mph 1843 14.80 0.10 108 31 94 0.71 0.10 0.30 767 237 1390 FAIL
25mph 1873 15.00 0.00 83 20 43 0.58 0.09 0.22 706 199 520 PASS
KyleS (1989 325i 121K mi - CA - 10.28.04 - Initial run, JimC chip, K&N filter+heat shield,
Ireland cat back exhaust, 4.10 diff - makes RPM's higher, New O2 sensor and
spark plugs 5K ago, ran 91 octane gas)
15mph 2050 15.40 0.20 108 31 75 0.71 0.10 0.10 767 237 571 PASS
25mph 2122 15.40 0.30 83 20 62 0.58 0.09 0.21 706 199 593 PASS
CO2 %O2 HC CO NOx
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
Gregg (1987 325is 220K mi - CA - 12.21.04 - Unknown condition)
15mph 1833 13.90 0.64 114 31 221 0.73 0.10 0.68 785 237 2925 GROSS POLLUTER
25mph 2028 14.31 0.38 88 20 178 0.61 0.09 0.43 724 199 1844 GROSS POLLUTER
Gregg (1987 325is 220K mi - CA - 02.11.05 - Hot soak, new plugs, new air filter, new O2 sensor,
oil change, fuel injector cleaner, CRC Guaranteed To Pass� Emissions Test
Formula [snake oil according to Gregg])
15mph 1914 14.00 0.56 114 31 187 0.73 0.10 0.65 785 237 3000 GROSS POLLUTER
25mph 1988 14.60 0.16 88 20 99 0.61 0.09 0.28 724 199 1178 GROSS POLLUTER
Gregg (1987 325is 220K mi - CA - 02.21.05 - New catalytic convertor, over $500 spent to get smogged!!!)
15mph 1771 14.90 0.02 114 31 59 0.73 0.10 0.03 785 237 45 PASS
25mph 1992 14.90 0.01 88 20 37 0.61 0.09 0.02 724 199 45 PASS
CO2 %O2 HC CO NOx
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
Grundler (1993 325iC 162K mi - CA - 04.18.05 - Initial run, original cat)
15mph 1971 15.2 0.0 86 21 89 0.50 0.06 0.32 697 150 309 FAIL
25mph 2055 15.4 0.0 51 13 44 0.48 0.05 0.11 724 136 46 PASS
Grundler (1993 325iC 162K mi - CA - 09.07.05 - Had local shop run cleaner thru injector system
and pistons, and flush "top-side clean" for $200)
15mph 1890 14.7 0.3 86 21 34 0.50 0.06 0.27 697 150 1 PASS
25mph 2020 15.0 0.2 51 13 10 0.48 0.05 0.07 724 136 8 PASS
%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS MAX AVE MEAS Results
mjbrox (1986 325es 107K mi - VA - 07.15.04 - Initial run)
15mph 0.73 0.72 1010ppm 983ppm PASS
25mph 0.77 0.90 919ppm 1034ppm FAIL
PeteinMD (1990 325i - MD - 06.03.04 - Initial run)
348.43 1.40 1.26 30.00 8.40 2.50 3.90 FAIL
PeteinMD (1990 325i - MD - 07.09.04 - Replaced O2 sensor)
348.53 1.40 2.32 30.00 13.58 2.50 3.89 FAIL
GregF (1987 325e 119K mi - OH - 08.04 - Initial run, all original emissions equipment)
14.2% 168.0ppm 173.3ppm 1.08% 2.22% 1208.0ppm 1159.3ppm FAIL
GregF (1987 325e ~119K mi - OH - 11.04 - Tried CRC Guaranteed To Pass�
Emissions Test Formula and the results were worse. Tried again
with just a new O2 sensor and passed.)
168.0ppm <70ppm 1.08% 0.5% 1208.0ppm <500ppm PASS

Original Smog Check
%CO2 %O2 HC (PPM) CO (%)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS Results
GregC (1989 325i 140K mi - CA - 03.11.03 - Cat replaced a couple years ago)
Low Speed 761 15.0 1.2 120 29 6 1.00 0.10 0.00 PASS
High Speed 2488 15.0 1.5 140 20 7 1.00 0.10 0.00 PASS
VietSB (1989 325i 127K mi - CA - 05.01.02 - All original emissions equipment,
Dinan chip, SuperSprint cat back exhaust)
Low Speed 764 14.0 1.1 120 29 69 1.00 0.10 0.14 PASS
High Speed 2493 14.5 0.3 140 20 19 1.00 0.10 0.19 PASS
Roadstergal (1986 325e 149K mi - WA - 05.29.04 - 20K mi on new engine gaskets
and valve adjustment, 15K on new O2 sensor, new-ish catalytic converter)
Idle 680 15.17 0.77 220 37 1.20 0.07 PASS
Cruise 1500 15.42 0.3 150 9 1.10 0.02 PASS
MikeG (1989 325iC - TN - 2004)
Idle 15.58 220 6 1.20 0.00 PASS
CO2 %O2 HC (Grams) CO (Grams)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS Results
Chris325/325i (1987 325 132K mi - IL - Replaced O2 sensor)
67.80 .407 .058 3.804 .718 PASS
Chris325/325i (1990 325i 148K mi - IL)
330.70 .538 .528 4.061 3.981 PASS

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	HC (PPM)	CO (%)	NO (PPM)
15mph	288	2.23	1982
25mph	238	2.11	1782

Original Smog Check
		%CO2	%O2	HC (PPM)			CO (%)
Test	RPM	MEAS	MEAS	MAX	AVE	MEAS	MAX	AVE	MEAS	Results
GregC (1989 325i 140K mi - CA - 03.11.03 - Cat replaced a couple years ago)
Low Speed	761	15.0	1.2	120	29	6	1.00	0.10	0.00	PASS
High Speed	2488	15.0	1.5	140	20	7	1.00	0.10	0.00	PASS
VietSB (1989 325i 127K mi - CA - 05.01.02 - All original emissions equipment, Dinan chip, SuperSprint cat back exhaust)
Low Speed	764	14.0	1.1	120	29	69	1.00	0.10	0.14	PASS
High Speed	2493	14.5	0.3	140	20	19	1.00	0.10	0.19	PASS
Roadstergal (1986 325e 149K mi - WA - 05.29.04 - 20K mi on new engine gaskets and valve adjustment, 15K on new O2 sensor, new-ish catalytic converter)
Idle	680	15.17	0.77	220		37	1.20		0.07	PASS
Cruise	1500	15.42	0.3	150		9	1.10		0.02	PASS
MikeG (1989 325iC - TN - 2004)
Idle		15.58		220		6	1.20		0.00	PASS
		CO2	%O2	HC (Grams)			CO (Grams)
Test	RPM	MEAS	MEAS	MAX	AVE	MEAS	MAX	AVE	MEAS	Results
Chris325/325i (1987 325 132K mi - IL - Replaced O2 sensor)
		67.80		.407		.058	3.804		.718	PASS
Chris325/325i (1990 325i 148K mi - IL)
		330.70		.538		.528	4.061		3.981	PASS