|
|
|
|
|
|
|
#1
02-25-2006, 06:09 PM
|
||||
|
||||
|
Failed Emission Test - 1989 420SEL
My 1989 420 SEL with 255,000 KM failed the provincial emission test. There is long list of what could be the problem. Here are the ASM tailpipe emission inspection results:
ASM 2525 HC PPM limit:50, reading:101, result:fail CO% limit .28 reading:.18 result:pass NO ppm Limit:548, reading:241, result:pass RPM 1414 result:valid Dilution: 15.6, result valid Curb idle HC PPM limit:200, reading:72, result:pass CO% limit 1.00 reading:.08 result:pass NO ppm Limit:N/A, reading:N/A, result:N/A, RPM 665 result:valid Dilution: 15.0, result valid Engine coolant temp 85c. I was told the high HC during driving test or high idle causes could be: vacuum leak ignition system malfunction faulty computerized engine management system and or oxygen sensor faulty air injection system internal engine problem failed catalytic converter In November 2005, I had a valve job done, new intake manifold o-rings, new chain and guides, new plugs, air filter, new head bolts, mercedes gaskets, oil change was about 1,000 KM ago, using 5w50 synthetic. o2 sensor is about 3 years old. Prior to valve job, had a rough idle. Mechanic who did valve job said definately part of the rough idle job problem was the 0-rings, they were hard`as rock, also said the my ezl was OK. The car runs great! Any ideas?
__________________
1989 420 SEL 
|
|
#2
02-25-2006, 06:38 PM
|
|||
|
|||
|
If your system is working properly in closed loop, I'd guess the catalyst is dying or was cold.
__________________
Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician
|
|
#3
02-25-2006, 07:25 PM
|
|||
|
|||
|
50 PPM is an awfully tight limit for ASM 2525. What has this limit been in the past?
I have recent California ASM results for a buddy's '87 560 SEL and it scored 42/74 on the 2525 test. In CA the 2525 test is preceeded by the 1550 test, which is the tough one. Dave's 560 was 70/100 and the best mine has been in recent tests is 73/116 on the 1550 and 47/91 on 2525. The 2525 is usually not a problem because the catalyst heats up during the 1550 test, which is the acid test if the catalyst isn't hot enough. There is no idle test in CA, but a move is on to add it. Your limit would probably fail most KE-equipped Mercs in California as few can score much under 50. I assume your test is only 2525 and idle? You didn't report the O2 level. Is it listed on your test report? There's appears to be a move to tightening limits in many jurisdictions to the point where more and more cars fail. Suggest you look at this thread and the others it links to: http://www.peachparts.com/shopforum/showthread.php?p=833484#post833484 I don't think there's really anything wrong with your car. If the O2 is zero, the HC can't get much lower. Relatively high HC is the nature of the KE-beast, which is why "conditioning" is so important. Old cats need to be REAL HOT! You may want to take the limit issue up with your emission test authorities. Duke Last edited by Duke2.6; 02-25-2006 at 07:31 PM.
|
|
#4
02-25-2006, 10:40 PM
|
|||
|
|||
|
Quote:
 Take all the C.A.R.B guys out back & shoot them ( ignorant S.O.B.s...everyone I've ever met). 
__________________
2007 C 230 Sport. 
|
|
#5
02-26-2006, 10:55 AM
|
||||
|
||||
|
Update
I do not have anymore readings from the inspection, everything was posted on first post. Yes, only the ASM2525 and the curb idle test, plus the gas cap pressure test are conducted. Apparently the limits were lowered in 2005.
The car was runnning for about 45 min. with a 15 min. highway run at 100 KPH but then it sat in for 50 min. in -5c temperature. The testor was 30 min. late. I actually went out and started the car about 5 min. before the test and got the coolant temp. backup to about 85c as the guy came out to get the car. When you say catalyst, is that the catalytic converter? and is that the part of the exhaust system, connected to the crossover pipe, where the o2 sensor is? The HC ppm reading is double the limit. How can I get the cat. hotter and what is the probability that it will be cut in half just becuase of heat, to less than 50 from 101? I do have a brand new complete exhaust system from timevalve, hanging on the garage wall. The existing exhaust is still in decent shape. Should I just replace the exhaust system? Should I go for a diagnostic to determine the reason for not meeting the emission standards? If I go for a diag., should I go to the dealer or any certified repair tech. shop, like the one that did the test? The emission report does state a repair cost limit of $450. I can get a conditional pass, if I spend at least $450 on emission related repairs (including parts, labour , diagnostics). The car cannot be sold with a conditional pass but I can get the plates renewed.
__________________
1989 420 SEL
|
|
#6
02-26-2006, 11:17 AM
|
|||
|
|||
|
Yes, catalyst and catalytic converter are the same thing. They are the first "units" after the 02 sensor, and your engine might also have "pre-cats" just aft of the exhaust manifold.
If you read my referenced posts you should understand that lack of proper "conditioning" is an absolute recipe for FAILURE. You must arrange that the car is tested immediately after a good warmup that includes high speed driving and brisk acceleration, and NEVER, EVER shut down the engine prior to the test. You have to "manage" your test. Letting the car sit for 50 minutes in sub-freezing temperatures is just not going to cut it, and idling the engine to warm the coolant will not get the catalysts hot enough. You're probably going to need to retard the timing by shorting the R16/1 resistor and disabling the vacuum advance as I discussed in the other threads. This is a lot easier and certainly cheaper than replacing the catalysts, which won't in and of itself gurantee a pass. Duke
|
|
#7
02-27-2006, 02:14 AM
|
||||
|
||||
|
Read up on the CIS/E system:
http://mb.braingears.com/126_DISC2/program/engine_420SEL.htm Check out 07.3 and be aware that there is a potentiometer attached to the CIS throttle plate which goes bad. They are available and can be replaced but need to be properly calibrated. You must also keep the car HOT as much as possible. Keep the car running while waiting for the test. My last emission test also had high HC so I'm probably going to have problems next year, emissions are tested every two years in Virginia.
__________________
Regards Warren Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL ENTER > = (HP RPN) Not part of the in-crowd since 1952.
|
|
#8
02-27-2006, 05:42 AM
|
|||
|
|||
|
Foot + Floor
Loop Until Exhaust = Glowing OR T=2min. Test Immediately  heheA lot of people around here fail emission tests so I tell them to go get their car nice and hot before they go. They still fail and I have them demonstrate "conditioning" the car...and honestly it doesn't cut it Let the beast under the hood come to life
|
|
#9
03-04-2006, 02:48 PM
|
||||
|
||||
|
Passed
I took the car into an "emission specialist" shop to get a diagnosis done. The guy quoted $60 to $120 for the diag., then whatever is wrong needs to be fixed, and then a retest is necessary. He asked me how much I was willing to spend,before he had to call me for authorization. I told him $200 is the limit. I called him 3 hours later, the car had passed, and the bill was $170 plus tax ($80 for diagnosis, $55 for combustion flush, $35 for emission test)
Here are the passed test results: ASM 2525 HC PPM limit:50, reading:37, result:pass CO% limit .28 reading:.14 result:pass NO ppm Limit:548, reading:46, result:pass RPM 1395 result:valid Dilution: 15.0, result valid Curb idle HC PPM limit:200, reading:38, result:pass CO% limit 1.00 reading:.08 result:pass NO ppm Limit:N/A, reading:N/A, result:N/A, RPM 661 result:valid Dilution: 15.0, result valid Very sweet! I am good to go for another 2 years. If anybody in the Toronto area wants the shop name/address, private message me.
__________________
1989 420 SEL
|
|
#10
03-04-2006, 09:35 PM
|
|||
|
|||
|
The diagnosis fee was a bribe to the cop that pulled him over while he was doing 120MPH performing the "combustion flush".
|
|
#11
03-05-2006, 12:10 AM
|
|||
|
|||
|
What diagnostics did he perform and what was the result?
What's a "combustion flush"? I take it you didn't witness any of this? I could have probably gotten it to pass by just driving it around the block hard a couple of times and then running the test as quickly as possible In CA we have a "tire dry test", which the tech can run on a wet day. As an experiment, I intentionally took my car in on a rainy day in January '01 and asked the tech to run the tire dry test, which is 30-60 seconds on the rollers with no load at about 25 MPH. He did this and then went right into the first test, which is 1550 and the HC was 87 ppm versus 121 two years prior against a limit of 141. O2 dropped from 0.4% to 0.0% so all the O2 was being used for oxidation by the catalyst. I attribute the reduction directly to the tire dry test which heated up the catalyst. The HC limit for my car dropped to 116 in '03 and after barely making the cut at 113/.1% O2, my new knowledge about the ignition map got me down to 73/0.05 O2 in '05, and I don't see how it can get any lower. Your first test was a marginal failure and was probably just a conditioning issue, but the car still has little margin. You're probably going to have to go through this drill every time. Or you can work on your spark advance map and properly condition the car yourself, and probably pass on the first try, which is what this guy might have done given the substantial reduction in NOx, which was exactly the response from my engine, too. Duke
|
|
#12
03-05-2006, 11:32 PM
|
|||
|
|||
|
Quote:
__________________
joel Prayers bring forth enlightenment.
|
|
#13
03-06-2006, 12:36 AM
|
||||
|
||||
|
Quote:
In BC I know this guy in Port Coq., and if your mercedes fails the Emissions test, all he does is retards the timing for you and your set. For a little bit more money he'll put it on the scope and check the readings first and you're almost guarenteed to pass with his first adjustment. Go back and he changes it back to normal. I think in this case, this is what the mechanic did to this guys car, passed him, and charged him all this free money and laughing all the way to the bank. p.s. Look to see if their's a hole in you're cat. Some mechanic's have this myth, that if you drill a small hole in the cat, it'll suck enough air in to dilute the readings. If you have to big of a hole, its going to say sample dilution and they won't be able to test you.
|
|
#14
03-05-2006, 11:02 PM
|
||||
|
||||
|
Info
HC is raw fuel. WHen you have to much air to fuel ratio, it can cause you to fail on the HydroCarbons. On newer mercedes and BMW's i've heard the Bosch Air Mass Meter has been a common culprit to high HC's, due to its premature death, but this is only what i've heard.
Below is the HydroCarbon break down from http://www.Aircare.ca they are the emissions company in BC. The company is under Translink control, however it is run by For Profit American company " ESP " under its Envirotest Canada division. In all ESP runs 80% of the emissions testing programs around the world. So all information you'll find under repairs on this site will directly relate to all emmisions programs. ----- Possible Causes of High Hydrocarbon (HC) Emissions Hydrocarbons relate to unburned fuel. You may logically think that must mean that the engine is getting too much fuel. However, that is only one of many possibilities ranging from fuel problems, to electrical problems, to internal engine problems such as piston rings that can cause HC emissions to be excessive. In order to pinpoint the cause of excessive HC emissions, the following systems (if applicable) will need to be checked, usually in the order shown below: Lean or Rich Air-Fuel Ratio For an engine to operate as designed, the correct ratio of fuel to air must be delivered to the cylinders. If the fuel system is delivering a leaner than ideal air-fuel ratio, it may result in lean misfire and cause high hydrocarbons. If the fuel system is too rich, it also may result in high HC but will be accompanied by high CO as well. For more info regarding the diagnosis of fuel delivery systems, see Fuel System Testing Inadequate Catalytic Converter Efficiency For vehicles that are 1988 model year or newer, it is very important that the catalytic converter be operating at 90% efficiency or better. That means that the emissions that come out of the tailpipe must be no more than 10% of what goes in. For more info regarding how to determine catalytic converter efficiency, see Catalytic Converter Testing Induction System Problems There are many aspects of the engine's air induction system (hoses, intake runners, intake manifold, vacuum-controlled devices) that can cause disruption in the air and fuel getting to the cylinders and result in high HC. Incorrect PCV valve/orifice flow rate can also cause similar symptoms. Leaking EGR valves also may cause excessive HC emissions. For more info regarding how induction system problems are identified, see Induction System Testing Poor Ignition Performance Ignition defects including dirty spark plugs, leaking or open-circuited spark plugs or wires, or defective ignition coils can all result in a shortage of spark energy. Any shortage of spark energy may cause high HC emissions. If the spark occurs at the wrong time, incomplete combustion and high hydrocarbons may result. Too much spark advance could be due to an incorrect adjustment or a defect in mechanical or vacuum advance mechanisms. For more info on testing ignition systems for inadequate spark energy or incorrect spark timing, see Ignition System Testing Uneven Output Among the Engine's Cylinders At this stage of the diagnosis the technician should be sure that the air-fuel ratio is correct, there are no external vacuum leaks, and the ignition system is operating normally. There are still many possible causes of high hydrocarbons, most of which are either internal engine problems or tough-to-detect induction system problems such as valve deposits or a leaking EGR valve. On fuel-injected vehicles, poor fuel atomization is a common cause of HC problems. For all of these remaining possibilities, checking for uneven power output amongst cylinders will usually help to track down the cause of the problem. For more info on testing for uneven power output, see Engine Integrity Tests ----- Quote:
|
 |
| Bookmarks |
|
|
Hybrid Mode
