CA Smog Failure Diagnosis?

moomoomeow · 07-16-2007, 07:00 PM

HC(PPM)
Max Meas
114 94
88 29

CO (%)
Max Meas
0.73 0.33
0.61 0.04

NO (PPM)
Max Meas
785 1353 !!!!!!!!!!!!!
724 648

As you can see, I had extremely high NO output.

Here is what i did prior to getting the car tested:

-Replaced Cat
-Replaced O2 Sensor
-Replaced Spark Plugs
-Changed oil
-Premium gas, with "Guaranteed to pass" formula, then refill with premium

The car is a NJ car being tested in CA, and it has NO EGR valve.

Last time I had it smogged (2 years ago), the NO output was HALF of what it was this time, and it just barely passed.

The car runs fine, the sparkplugs look fine, the oil looks fine, the coolant looks fine, and the exhaust looks fine.

What is wrong with my car?!?!

To remove this ad, register today or login if you already are registered!

E4///Turbo · 07-16-2007, 08:20 PM

[-Premium gas, with "Guaranteed to pass" formula, then refill with premium

What the heck is that?
hope it is not one of those $7.99 a bottle formulas that is Guaranteed to make the seller rich that people find in Auto parts stores and actually believe it will do anything but take their money,and don't bother trying to get your money back as you have used up the "Guaranteed to pass" formula and most certainly they won't take back your empty bottle and failed report...I am no
expert but I have repaired 100's if not 1000's of failed
Vehicles since the 90's and do hold a current California Inspectors license...

moomoomeow · 07-16-2007, 08:37 PM

it is just a fuel system cleaner, like techron etc...

MarcusF · 07-18-2007, 10:26 AM

When an engine is tuned to produce low CO and HC numbers, it typically produces high NOx numbers. That's because as the combustion chamber temperatures increase, the engine runs hotter, and the hotter an engine runs, the more NOx it produces.

What can you do? The combustion temperatures can be brought down by (1) retarding the timing (provided the tech doesn't care if the timing isn't on spec - not likely), (2) run richer (this will increase the HC level, but your numbers indicate you have room to maneuver), or (3) install/fix/do whatever is required to get a functioning EGR - which will lower combustion chamber temperatures.

phantom2 · 05-27-2009, 12:43 AM

I also have a issue with smog check, my #s are
15mph HC max 81 meas 197 CO max .47 meas .63 NO (PPM) max 685 meas 1168
25 mph HC max 47 meas 188 CO max .44 meas .44 NO (PPM) max 696 meas 1632
Have not done anything yet, thinking egr valve, what else? last tune up was less than 10K ago. 93 400E
Thanks

c32amg13 · 06-05-2009, 11:49 PM

just pay $150 to pass the smog. take out the cat. & use a straight pipe to a good amg. remus, brabus, lorinser, etc...man you will feel a big difference. feels like u have a header. if u want it quiter, use a pre-silencer, instead of a cat. then u can use a magnaflow freeflow, which is all s.s., looks nice & cheaper than the $1000 mufflers.

07-18-2007, 10:26 AM	#4
MarcusF MBWorld Fanatic! Garage is empty, add now Join Date: Apr 2005 Location: SCV SoCal Posts: 3,004 Drives: 2002 CLK430	When an engine is tuned to produce low CO and HC numbers, it typically produces high NOx numbers. That's because as the combustion chamber temperatures increase, the engine runs hotter, and the hotter an engine runs, the more NOx it produces. What can you do? The combustion temperatures can be brought down by (1) retarding the timing (provided the tech doesn't care if the timing isn't on spec - not likely), (2) run richer (this will increase the HC level, but your numbers indicate you have room to maneuver), or (3) install/fix/do whatever is required to get a functioning EGR - which will lower combustion chamber temperatures. __________________ Mercedes-Benz Performance and Specifications ♦ Signal to Noise Los Angeles Section of the Mercedes-Benz Club of America ♦ Orange County Section of the Mercedes-Benz Club of America

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

07-16-2007, 08:20 PM	#2
E4///Turbo Member Garage is empty, add now Join Date: Mar 2007 Location: California,Washington,St.Croix Posts: 203 Drives: Very Slow Mercedes	[-Premium gas, with "Guaranteed to pass" formula, then refill with premium What the heck is that? hope it is not one of those $7.99 a bottle formulas that is Guaranteed to make the seller rich that people find in Auto parts stores and actually believe it will do anything but take their money,and don't bother trying to get your money back as you have used up the "Guaranteed to pass" formula and most certainly they won't take back your empty bottle and failed report...I am no expert but I have repaired 100's if not 1000's of failed Vehicles since the 90's and do hold a current California Inspectors license...

07-16-2007, 08:37 PM	#3
moomoomeow Newbie Garage is empty, add now Join Date: Aug 2002 Posts: 4	it is just a fuel system cleaner, like techron etc...

05-27-2009, 12:43 AM	#5
phantom2 Newbie Garage is empty, add now Join Date: Aug 2007 Posts: 4	I also have a issue with smog check, my #s are 15mph HC max 81 meas 197 CO max .47 meas .63 NO (PPM) max 685 meas 1168 25 mph HC max 47 meas 188 CO max .44 meas .44 NO (PPM) max 696 meas 1632 Have not done anything yet, thinking egr valve, what else? last tune up was less than 10K ago. 93 400E Thanks

06-05-2009, 11:49 PM	#6
c32amg13 Member Garage is empty, add now Join Date: Jun 2003 Location: eagle rock Posts: 82 Drives: c32, 190e, m3, porsche 930, prelude 4ws, mazda rx3-sp	just pay $150 to pass the smog. take out the cat. & use a straight pipe to a good amg. remus, brabus, lorinser, etc...man you will feel a big difference. feels like u have a header. if u want it quiter, use a pre-silencer, instead of a cat. then u can use a magnaflow freeflow, which is all s.s., looks nice & cheaper than the $1000 mufflers.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)