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420SEL
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Discussion Starter #1 (Edited)
Lately I’ve been getting a faint fuel smell inside the car.

I checked under the hood and nothing smells like it in the engine bay.
I do have a small exhaust leak under the back seat, kidneys i suppose. I haven’t planned fixing it yet as it’s too small.
But since I do drive my kids around during weekends in it I’d like to get it figured out.
I found a vacuum line going from the throttle body to the side of the fender where ezl is came off the check valve because the rubber grommet developed a tear in it. It’s a larger diameter to smaller 90 degree rubber part that’s very small. I taped it up for now and plugged it back in. I ordered a new part.

Other than that what else can it be?

Gals cap does make a small whoosh sound when I open it. So some pressure in the tank is there for sure.

Car runs fine. All new vacuum tubes and I take gaskets and all that Jazz under hood.

Thank you.


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1986/1990 W126
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13,551 Posts
MB fuel cap? Seal needs to be good, and fully tightened after filling.

Fuel tank check valve should be checked /replaced and lines to charcoal cannister checked for open-ness.
You'll find info in the archives, pressures etc have been posted and I think the part number of the fuel tank pressure check valve. Super easy and cheap to replace.
 

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1991 560Sec
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71 Posts
My charcoal canister lines were straight up leaking drops of fuel. But if I recall correctly mine seemed to smell of fuel when I turned on ac/heat so the fan seemed to pull mine in. I don’t think I found a solution before I tore the whole car up. Wondering if yours is the same when turning the fan on.
 

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420SEL
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Discussion Starter #4
My charcoal canister lines were straight up leaking drops of fuel. But if I recall correctly mine seemed to smell of fuel when I turned on ac/heat so the fan seemed to pull mine in. I don’t think I found a solution before I tore the whole car up. Wondering if yours is the same when turning the fan on.
Thanks for bringing that up. Now that I think about it, that could be it as I have climate control on auto most times.

Where is the canister ? Where should I look for the leak?

Thanks.


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420SEL
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Discussion Starter #6
Great thanks. I’ll take a look at it this weekend.


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At this age of car it’s time to completely replace all rubber fuel lines for the rear fuel pump all the way to in the engine compartment . There have been many w126 fires in this forum due to fuel lines failing as a result of ethanol in modern gas . These should be replaced NoW whether or not you see fuel leaking

another source Of possible fuel leakage is the eha. Check it .
 

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420SEL
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Discussion Starter #8
Thanks. I’ll look it over.
Eha o rings are new. They were replaced when I was doing all the intake gaskets.


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