over rich fuel mixture condition
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MBWorld Fanatic!
Joined: May 2009
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From: Chicago (Palos Park)
2023 CLA 250, 2021 GLC43, 2003 CLK320
over rich fuel mixture condition
Hi, we had a very cold weather today for Chicago at about 1 and after work when I got off the train it was about 3. I have about 8 miles drive home and I stopped at the store on the way back. Once I got to the garage, I backed up and getting out of the car I could smell exhaust/ gas. I never smelled that before so got alarmed. There was no smell inside the car or the trunk. I could not find any fuel leak. I let the car sit for maybe 40 min and checked back. I could still smell it, a bit less and no leaks I could locate.
I checked the air filter cover and it was sitting fine. Is it possible that due to the extreme cold and short drive I experienced over rich fuel mixture condition?
Thanks
Darius
I checked the air filter cover and it was sitting fine. Is it possible that due to the extreme cold and short drive I experienced over rich fuel mixture condition?
Thanks
Darius
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
You will be running winter fuel Chicago which has more light ends so you will be more inclined to notice the smell. Presume the gas cap is on properly. It should trigger an EECS warning.
Thread Starter
MBWorld Fanatic!
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From: Chicago (Palos Park)
2023 CLA 250, 2021 GLC43, 2003 CLK320
Thanks, yes the cap is fine, no errors. Before that I drove the car on Sunday morning with 15 F temps for maybe 6 miles for a mountain bike ride on the local single tracks. No smell then and the car was outside for the 2.5 hour ride.
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A common problem is leaks from the seal rings on top of the tank where the fuel sender and fuel pump attach. Cold weather makes them shrink and they can leak fumes, usually very strong under the rear wheel wells. The parts are less than $40 for both of tem, and changing them is fairly easy - remove the seats, remove the access covers, unscrew the seal clamps, replace the seals.
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Joined: Jun 2008
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
I thought of that Rudney but the OP's car has the old bottle jar caps & not the newer circular clamps. Have you seen this problem with the old rings? I've only experienced it with the clamps. We don't experience your huge temperature swings.
Thread Starter
MBWorld Fanatic!
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From: Chicago (Palos Park)
2023 CLA 250, 2021 GLC43, 2003 CLK320
well I went to the garage this morning and can't smell much anymore. I'm working from home today but maybe I will take the car out for a short drive and see whats going on. By noon it should be warmer at 21 
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Thread Starter
MBWorld Fanatic!
Joined: May 2009
Posts: 1,031
Likes: 8
From: Chicago (Palos Park)
2023 CLA 250, 2021 GLC43, 2003 CLK320
I will see today if the smell is going to be there. Its a bit warmer here in Chicagoland today. On the train back now so will know in an hour.
I will have to google a bit to find some details on the seal rings.
I filled up the tank two days earlier and only put on maybe 20 miles so the tank was almost full 
I will have to google a bit to find some details on the seal rings.
Cold weather and a full tank of gas is a big contributor.
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Thread Starter
MBWorld Fanatic!
Joined: May 2009
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From: Chicago (Palos Park)
2023 CLA 250, 2021 GLC43, 2003 CLK320
Glyn, are the seal rings the Sectional sealing rings (item 12 and 14) shown in the PDF in your old post here:
https://mbworld.org/forums/4781093-post6.html
Thanks
Darius
https://mbworld.org/forums/4781093-post6.html
Thanks
Darius
Thread Starter
MBWorld Fanatic!
Joined: May 2009
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From: Chicago (Palos Park)
2023 CLA 250, 2021 GLC43, 2003 CLK320
