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  #1  
Old 03-08-2007, 08:50 PM
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Failed emissions test-77 450sel

My 1977 450 sel just failed the emissions test. Here are the results:
HC: 525ppm, limit 500ppm
CO: 9.41%, limit 5.0%
CO2: 8.04
Last year it passed with flying colors. I did have to sit in line for about 10 min. and I know that will cause the cat converter to cool down, but I did try to keep the rpms up to keep it hot.
It is showing the following symptoms. When the engine gets hot the rpms will drop to below 500 and will miss,shake, and run rough. When warming-up the rpms will vary from 1300-750 depending on the temp outside and the mood of the car. I have replaced the fuel accumulator and warm-up regulator since the last inspection. I have dumped quite a bit to Tecron into the gas and drive quite a bit on the interstate at 75 mph. The distributor cap, rotor, and wires are 12 years old and have about 25k on them. The cap has minor carbon tracking, but looks ok. Within the last 10,000 the car has had plugs, fuel filter, 3 oil changes, air filter.
Where should I start. I am pretty sure the problem is coming from the low crappy idle causing all the unburned fuel in the exhaust.
Thanks

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1997 Land Rover Discovery 158,000
1995 E320 Wagon 132,000mi
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  #2  
Old 03-09-2007, 11:47 AM
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Where do you live that they test emmisions on a 30 year old car?
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With best regards

Al
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  #3  
Old 03-09-2007, 12:18 PM
david s poole
 
Join Date: Mar 2005
Location: dallas
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two obvious clues,when you replaced the accumulator you eliminated a drain on fuel volume so the adjustment behind the plate needs to be leaned down to compensate for it.you also replaced the warm up regulator and this changed the control pressure and will require the same adjustment.call me if you need a better explanation.
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4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
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  #4  
Old 03-09-2007, 12:26 PM
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I've heard that New Jersey and Arizona are testing back to '68, California back to '75 and some Canadian provinces are testing '50s cars.

As for this 450SEL, 9.41 % CO is way too high. You need to lean that fuel injection down some. Possibly the accumulator and regulator might be a factor here. Why were they replaced? Did you install new or used? If you still have them, maybe reinstalling the old ones could improve things enough to pass.

Happy Motoring, Mark
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  #5  
Old 03-09-2007, 02:30 PM
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Thanks for the replies. I live in Tennessee and in most counties they require emissions testing for vehicles 1976 and above.
The reason for the fuel accumulator and warm-up regulator was a cold and hot start problem. They cleared it right up. I guess I need to take it in and get the mixture adjusted. I have noticed I am getting bad fuel economy, not that these cars were great to begin with.
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1997 Land Rover Discovery 158,000
1995 E320 Wagon 132,000mi
1999 E320 Wagon 97,000mi
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  #6  
Old 03-09-2007, 02:35 PM
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Sorry, both were new parts. The warm up regulator has a different part number from the old one but the new one crossed referenced to the old part. The only difference is the vacuum port is bigger on the new one. I hope I did not install the wrong part.
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1997 Land Rover Discovery 158,000
1995 E320 Wagon 132,000mi
1999 E320 Wagon 97,000mi
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  #7  
Old 03-09-2007, 04:02 PM
david s poole
 
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no you didn't that is correct.
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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg
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  #8  
Old 03-10-2007, 12:01 AM
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Before you spend too much time getting the CO2 set, swap the vacuum hoses on the warmup regulator. It could be that the new version has the vacuum and vent connections reversed from the old one. That's what happened to me.

I was running 8.5%+ at idle because it was running in full load enrichment mode due to vacuum at the vent line.

You should notice an immediate improvement if they are indeed connected differently.

For mine, it's vacuum at the top connection and vent on the connection facing the rear of the car.

Michael
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  #9  
Old 03-10-2007, 09:03 AM
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Wow, that is interesting. I will swap them and report back.
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  #10  
Old 03-10-2007, 11:40 AM
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Well that did it. It runs like a champ now. Perfect idle, start up, and now it does not have raw fuel spitting out of the tail pipe. I would have never figured out swapping the lines on the warm-up regulator. I can't thank you enough!!!
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  #11  
Old 03-10-2007, 02:08 PM
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Nice wrench, 250 Coupe!

You might want to put a new set of plugs in it now.
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  #12  
Old 03-10-2007, 04:27 PM
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Quote:
Originally Posted by ctaylor738 View Post
You might want to put a new set of plugs in it now.
And check the oil for gas dilution. Maybe go ahead and change it just to be safe.

Happy Motoring, Mark
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  #13  
Old 03-22-2007, 08:42 PM
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Went to get the emmissions ckecked again and Failed, again. Here are the latest results:
HC 220-Passed
CO 5.13%-Failed (5.0% max)
CO2 9.13
The readings were much improved and it was very close to passing. There was a 10 minute line. They check the car at idle and at 2500 rpm. The idle rpm was about 1000 when they checked. When the engine gets hot or after an interstate drive the rpms will drop to about 500 and miss. Sometimes it is perfect. Could it be a vacuum leak, improper adjustment in the fuel system? Hopefully you guys will give me another miracle answer. Thanks again.
P.S. changed the oil per earlier post
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1997 Land Rover Discovery 158,000
1995 E320 Wagon 132,000mi
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  #14  
Old 03-23-2007, 09:49 AM
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No ideas about the "500 and miss. Sometimes it's perfect", but the CIS unit should have a CO adjustment hole located between the fuel distributor and the air intake. As I recall, it takes a long 3mm allen, but I don't remember which direction it turns to lean it.
Sounds like if you can adjust it, while it's running like it did during the last inspection, you're so close it should pass, but that could be real tricky without a CO meter.

Happy Motoring, Mark
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  #15  
Old 03-23-2007, 10:31 AM
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AZ does indeed test both diesel and gas back to 67. Next year it should be 68. Increments each year. One of the principal reasons I've not tried buying one of my favourite cars since moving here. 108's 116's, 114's 115, 123's 124's are all subject to draconian emissions tests. Now that I have a couple of cars I'm able to consider one of them but after the nightmare I went thru with my 82 Buick I'll never be reliant on a single old vehicle in Phoenix again. I'm following this thread with interest for obvious reasons.

- Peter.

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