Just went thru Emissions - PeachParts Mercedes-Benz Forum

pj67coll · #1 12-29-2015, 01:39 PM

It's coming up on a year since I bought the 240D so I had to go thru emissions today. Judging by the amount of soot that blew out when they started the test, and the fact that their machine was on the blink and they had to do it over I was worried. But it went thru with 0.7 ppm, fail is 20. So hell. I don't see how it could be any better. Either their machine is malfunctioning or I have about the cleanest burning OM616 out there

- Peter.

tjts1 · #2 12-29-2015, 01:47 PM

Emissions testing on a 35 year old diesel?

LOL

Dan Stokes · #3 12-29-2015, 02:11 PM

0.7 PPM of what? There are at least 4 major gasses that can be tested as well as particulate matter (PM) for a Diesel. Sounds like a CO value but I don't know the particulars of Arizona smog laws. Diesels are inherently low in HC and CO, OK for CO2 (tied to fuel economy) and not good on NoX ( a product of high combustion chamber temps and relatively long burn times). PM is hard to measure with any accuracy in a screening situation - that would relate to the smoke screen you mentioned and evidently not tested.

Dan

pj67coll · #4 12-29-2015, 02:25 PM

In Maricopa county they test diesels every year. The reading is for particulate. They don't test the other readings fortunately. When I bought the car a year ago I drove straight to the testing station and it went thru with 3.1 ppm particulate reading out of 20ppm which is the cut off. This reading was staggeringly low.

I did a long high speed freeway run for about 10 minutes before I went to the station. I do this with all my cars before emissions. Got up to 75 at one stage which is something I never do with this car. I pulled in to the station and there were only a few cars in front of me. So I only waited about 5 minutes. The guy couldn't find the parking brake release! so the first time he was fighting that and it was blowing quite a bit of smoke out before he stalled it!

Then the machine shut down and they had to wait while it re-calibrated. Then the second time there was quite a bit of smoke at the beginning of the test but it cleaned out as the revs increased. They run the plume thru a device that shines a beam to a reflector which I guess is how the particulate is measured.

They also check for any emissions device tampering and the gas cap but as my car has no catalyst and I keep it all original it was all good.

- Peter.

Dan Stokes · #5 12-29-2015, 04:15 PM

Well, no. They aren't measuring PM, they're measuring opacity which is NOT well correlated with PM. It IS, however, what the public *****es about! I don't know if this is still the case but for many years the Federal emissions test required actual PM testing (done gravimetrically over the course of a transient emissions test on an engine dyno) and eventually an opacity test done as a separate testing sequence. There's all sorts of data to demonstrate that PM and opacity are barely acquainted with each other as every Diesel engine certification test for years had both PM values and opacity results.

Maricopa County is cheaping out so that it LOOKS like they're doing something when really they could get about the same result by shining a flashlight thru the plume! Send them to me if they want to do REAL testing - they wouldn't like what I have to tell them (takes about $2M minimum to even start getting set up to do meaningful testing).

Glad you passed.

Dan

mannys9130 · #6 12-29-2015, 04:57 PM

Quote:

Originally Posted by tjts1

Emissions testing on a 35 year old diesel?

LOL

Tucson and Phoenix metro have yearly exhaust opacity tests on diesels going back all the way to the mid 60s.

I take my 190D in every year, and every year it passes under 1% out of 20% limit. Naturally aspirated diesels will almost never fail unless something is seriously wrong. Turbos will only fail if you've tampered with the the ALDA.

pj67coll · #7 12-29-2015, 07:22 PM

Quote:

Originally Posted by mannys9130

Naturally aspirated diesels will almost never fail unless something is seriously wrong. Turbos will only fail if you've tampered with the the ALDA.

Interesting. According to the PO's service records it failed with 26% a couple of years ago. He did a valve adjustment, new air filter, diesel purge, and "Italian tune up" then went thru again with bio-diesel in the tank and it passed with about 5%.

When I bought it as I said I went thru immediately and it passed with 3.1%.
I subsequently fixed the air cleaner mounting issue and cleaned a heck of a lot of congealed oil and gunk out of the filter housing, put in a new air filter and fixed the pipe that goes from top of the manifold to the air filter housing. I've not done a valve adjustment yet but I guess probably the new filter along with cleaning it up a bit and running it hard right before this test got it down to such a low percentage.

I looked at the printout again and I see that it's an opacity reading, not "Particulate" specifically. Glad about that I am. I'm pretty sure its due for a vale adjustment so I'll be getting around to that one of these days soon I think.

- Peter.

mannys9130 · #8 12-29-2015, 07:42 PM

I said they will pass unless something is seriously wrong.

If he failed, and a valve adjustment fixed it, he was badly in need of that service. Tight valves cause compression loss. The diesel purge probably cleaned up the nozzles so the spray pattern was better, and driving like you stole it loads up the engine and the higher temps burn excess Carbon out of the prechamber. That's why he passed the second time.

If you do the valve adjustment for the first time, make sure to set them correctly and then drive it hard for 500 miles. Then do another adjustment and seal it up for 15k miles. If it's been a while, Carbon builds up where the valve margin is supposed to sit on the seat. After your initial adjust, the crud will wear away and the valves will need to be adjusted again. After the second one, you'll be set.

Diesel911 · #9 12-29-2015, 10:33 PM

2 weeks ago here in S CA I saw a roadside stop where they were randomly emission testing vehicles. They even had a portable roller setup so the back Wheels could spin during the Emission test.

I was on the opposite side of the Road from it.

I have not seen one of those since about 1994 at which time the waved me on by. I was driving my Volvo Diesel so I doubt if I would have been checked.

If I had been stopped in the Mercedes I have the EGR disconnected and they would have seen that.

BillGrissom · #10 12-29-2015, 10:48 PM

Quote:

Originally Posted by Diesel911

2 weeks ago here in S CA I saw a roadside stop where they were randomly emission testing vehicles.

Sounds "intrusive". Was this a surface street or freeway? I wonder if they only stop cars that appear to be polluters or if truly random. I think there is a state provision for the former, and have heard of "across the road" sensors to try to identify specific cars. My EGR is also removed, and I expect my car pollutes less without that complicated contraption that may not have been working correctly. Don't know if they would have details on what my engine is supposed to look like.

sloride · #11 12-29-2015, 11:40 PM

Quote:

Originally Posted by BillGrissom

Sounds "intrusive". Was this a surface street or freeway? I wonder if they only stop cars that appear to be polluters or if truly random. I think there is a state provision for the former, and have heard of "across the road" sensors to try to identify specific cars. My EGR is also removed, and I expect my car pollutes less without that complicated contraption that may not have been working correctly. Don't know if they would have details on what my engine is supposed to look like.

I doubt they know where to look for the BB's.

tjts1 · #12 12-29-2015, 11:42 PM

Quote:

Originally Posted by Diesel911

2 weeks ago here in S CA I saw a roadside stop where they were randomly emission testing vehicles. They even had a portable roller setup so the back Wheels could spin during the Emission test.

I was on the opposite side of the Road from it.

I have not seen one of those since about 1994 at which time the waved me on by. I was driving my Volvo Diesel so I doubt if I would have been checked.

If I had been stopped in the Mercedes I have the EGR disconnected and they would have seen that.

Its strictly voluntary, you can refuse. They are doing it to test the smog check stations which are notorious for cheating, not the owners of the cars. There is not pass/fail here for you. I was stopped at one of those in Sacramento in my 190e. I told the officer that I don't have time and drove away.
http://www3.epa.gov/otaq/regs/im/roadside.pdf

Quote:

4.3: Inspection Protocol
Currently, AQR teams use the following test procedure. Using the random sample method, a
CHP officer selects vehicles and directs them into the test lane as soon as the test of the previous
vehicle is complete. The greeter explains to the driver that the test is part of a survey to evaluate
the Smog Check Program and that there are no penalties, emissions-related or otherwise,
associated with the test. The BAR greeter also provides the driver with a consumer information
handout (Appendix D) that further explains the Roadside Inspection Program. If the driver
agrees to participate in the inspection process, the vehicle is inspected. If the driver refuses, the
vehicle is released and another vehicle is quickly directed into the test lane. The license plate
numbers of vehicles whose operators decline to participate in the Roadside Inspection Program
are recorded and entered into a laptop computer for later analysis.
A similar process exists if the team is using the stratified sample method. However, once the
vehicle enters the test lane and stops at the appropriate location, the BAR greeter determines the
vehicle model-year. Using a worksheet providing model-year stratification, the greeter
6
determines the model-year of the vehicle. If the vehicle is one of the desired models, the driver
is asked to participate in the Roadside Inspection Program. If it is not, the driver is thanked for
their time and the vehicle is directed out of the lane. Note that every driver has the option not to
participate. All testable vehicles receive a 90-second ASM 5015 and a 60-second ASM 2525
test

pj67coll · #13 12-30-2015, 12:12 AM

Quote:

Originally Posted by tjts1

Its strictly voluntary, you can refuse.

Quote:

The license plate
numbers of vehicles whose operators decline to participate in the Roadside Inspection Program
are recorded and entered into a laptop computer for later analysis.

So what happens then. You get a hammering on your door in the middle of the night from the Smogstapo?

- Peter.

tjts1 · #14 12-30-2015, 12:14 AM

Quote:

Originally Posted by pj67coll

So what happens then. You get a hammering on your door in the middle of the night from the Smogstapo?

- Peter.

I don't know but they better hurry up because its been 2 years now and I'm still waiting.

Again (for the benefit of the reading impaired) the program exists to keep the smog check stations honest, not to penalize the car owners. They are looking for cars that fail the road side test within 90 days of a routine biannual smog check. If they find that one smog check station is passing a lot of cars that fail the road side test that station can get fined or have its license revoked.
https://www.bar.ca.gov/Consumer/Roadside_Inspection_Program.html

http://www.arb.ca.gov/msprog/smogcheck/march09/roadsidereport.pdf

Quote:

For pre-1996 model year vehicles that fail their initial Smog Check inspection
and receive a passing score on a re-test, 40% were failing again on the roadside
within a year of the passing test.
It should be noted that the 40% failure rate referenced above applies to the exhaust
emissions standards and does not account for visual or functional inspection failures
present in vehicles that passed the tailpipe standards. Based on Roadside data collected
between February 2003 and April 2006, the percent of pre-1996 vehicles failing the
emissions test at the roadside within one year of passing a re-test at a Smog Check station
has increased from 40% to 49%. When visual and functional failures are included, the
Roadside failure rate for vehicles that failed the initial inspection during their previous
Smog Check increases to 59%.1

Diesel911 · #15 12-30-2015, 11:17 AM

Quote:

Originally Posted by BillGrissom

Sounds "intrusive". Was this a surface street or freeway? I wonder if they only stop cars that appear to be polluters or if truly random. I think there is a state provision for the former, and have heard of "across the road" sensors to try to identify specific cars. My EGR is also removed, and I expect my car pollutes less without that complicated contraption that may not have been working correctly. Don't know if they would have details on what my engine is supposed to look like.

Surface Street.

On my 300D when I removed the Intake Manifold I found that the EGR Port was entirely plugged with Carbon. So it was not working anyway.