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1991 300CE / Smoke Silver
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Discussion Starter #1
Hello everyone out in 124 land!

I have a 1991 300CE with the 104 engine. The car has approximately 85k miles on it and appears to have been well maintained by the previous owner (I recently bought the car -- when it had 80k miles on it).

The problem I am experiencing is a very strong smell of gasoline inside the cabin. It should also be mentioned that the fuel pump in the rear also drones on quite loudly (although it has been this way since i bought the car).

Any ideas or theories as to what could be the cause of the strong smell? :confused:

Season's greetings!

Wes
 

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2008 E350 4M, 2016 Audi Allroad, 2019 Audi Q5
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5,447 Posts
Is that with the LH-SFI or CIS-E?
 

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1989 300E 125,000 miles, 2005 Acura TL, 2011 Hyundai Elantra Limited
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201 Posts
Gas Smell

My 89 300E had a strong odor of gas especially in the garage. Turned out the small rubber hose from the fuel pump to the metal line had a hairline crack and began to leak. This custom hose cost under $25 to replace and I changed the fuel filter at the same time!
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,746 Posts
Remove your air filter box and look at the EHA valve. Where it meets the fuel distributor, the seals could be leaking. Pics below

Jayare
 

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1988 M-BENZ 300E | 1991 FORD PROBE GT TURBO | 2003 FORD EXPLORER 4x4
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684 Posts
Ethanol in today's crap gas eats up EHA's. If smelling it in the cabin it's most likely the EHA, I once had a leak at the pump and could not smell that one in the cabin.
 

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W124
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5,169 Posts
If a 104 has an EHA it is most likely the culprit. The cabin air intake is a foot or two away from where these buggers leak. From my experience the EHA is shot when this happens and not something you can remedy with new o rings. These are poorly designed and built and fail too often. I have put three into my wife's low mileage '89 over the last ten years and just replaced one on my '88. They ain't cheap at $260 a pop and I learned with the most recent replacement that they can change your fuel mixture noticeably. I took the EHA out of the box and installed it like I did the other three without any adjustment to it. Well this time it caused the fuel mixture to go so rich it cost me the cat pipe before I realized what was going on. EHA's may seem easy to change but unless they are set up perfectly from Bosch (yeah right) or you plan on adjusting both the EHA and the duty cycle, this is best left to a professional IMO.
 

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Premium Member
About a dozen 1988, 1989, 1990, and 1991 sedans, wagons, 4Matics and 1 coupe
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5,466 Posts
Another vote for the EHA. And I agree that the o-rings are probably not the problem (but you can hope). In two cases I've seen the fuel was seeping out of seams in the EHA. Not gushing, not spraying. Just enough leakage to keep the EHA wet but it sure did stink of gas. I'd look there first.

However...

My sedan did have a bad hose at the fuel filter outlet. Many years ago I was driving in warm weather with the sunroof open. Gas stink was awful and coming *in* via the open sunroof. When I pulled over to investigate I saw a strong stream of fuel spraying from above the differential. ??? It was the short hose connecting the fuel filter outlet to the hard line heading forward to the engine.
 

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1989 300E 125,000 miles, 2005 Acura TL, 2011 Hyundai Elantra Limited
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Another vote for the EHA. And I agree that the o-rings are probably not the problem (but you can hope). In two cases I've seen the fuel was seeping out of seams in the EHA. Not gushing, not spraying. Just enough leakage to keep the EHA wet but it sure did stink of gas. I'd look there first.

However...

My sedan did have a bad hose at the fuel filter outlet. Many years ago I was driving in warm weather with the sunroof open. Gas stink was awful and coming *in* via the open sunroof. When I pulled over to investigate I saw a strong stream of fuel spraying from above the differential. ??? It was the short hose connecting the fuel filter outlet to the hard line heading forward to the engine.
Yea, that was the hose that leaked on mine too!
 

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W124
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Yea, that was the hose that leaked on mine too!
+2 I had that happen to the wife's '89 but I only smelled the fuel after getting out of the car; it didn't seem to work its way up front so the blower could pull it into the cabin. Nonetheless, this is another failure point and all 124s need this hose replaced eventually. When mine failed it chose to do so a week after I had just seal-coated the driveway so in hindsight, I should have replaced it before it failed - at the last fuel filter change. But heck, you live and learn and this website is great for learning from other peoples' experiences.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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Adjusting the EHA so that the bottom port on your fuel distributor yields more bar pressure is detailed in Bentleys "The Bible". It' supposed to compensate somewhat for a worn CIS and you'll notice better starts. You have to recheck the duty cycle of course, after you boost the pressure.

Kevin
 

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2005 E320 CDI, 1992 300TE, 1999 Porsche 911 Cabriolet
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368 Posts
I too had the leaky pissing hose from the filter to the metal line and it too only smelled when the car was parked. Creepy as I had a car burn up 30 years ago for a leaky fuel line.

So despite the common fuel line failure, I will go with the EHA valve guess. I've adjusted mine a couple of times over the last 18 years and I have to relearn it each time but it's not too difficult.

Good luck,
Peter
 

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1991 300CE / Smoke Silver
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25 Posts
Discussion Starter #12
Thanks to all who offered up their thoughts and recommendations... :bowdown:

I will have to have a look under the hood at that damn EHA valve and see if that's the culprit. In the meantime, I'm not going to catch on fire am I?!? :eek:

Happy New Year to everyone! :thumbsup:
 

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1991 300CE, 1992 300CE, 1995 E320, 1998 E320
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wildwildwes, best to remove the air filter housing and start the engine when it's cold to check for a weeping EHA valve. Engine heat will evaporate the leaking gas so you won't be able to tell if the EHA has a hairline crack and leaks.
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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"Will I catch on fire?"

Let's see Wes, most likely you have leaking raw fuel on a hot motor, surrounded by several electrical connections. When was the last time you saw gasoline not ignite with a spark?

Jayare
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,393 Posts
"Will I catch on fire?"

Let's see Wes, most likely you have leaking raw fuel on a hot motor, surrounded by several electrical connections. When was the last time you saw gasoline not ignite with a spark?

Jayare
:D

Kevin
 

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1991 300CE / Smoke Silver
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Discussion Starter #17
"Will I catch on fire?"

Let's see Wes, most likely you have leaking raw fuel on a hot motor, surrounded by several electrical connections. When was the last time you saw gasoline not ignite with a spark?

Jayare
Hmmm... Well Jayare, thanks for the rye humor, but I was kind of hoping for a more thoughtful answer... Ever seen a mechanic smoking while working on your car? I have... Never witnessed an explosion or a car catching on fire -- yet. KNOCK ON WOOD.
 

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89 300E; 00 E320
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2,515 Posts
How about this Wes? If you use the car the way it is, you could kill yourself and anyone else within 100 feet.
 

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1988 M-BENZ 300E | 1991 FORD PROBE GT TURBO | 2003 FORD EXPLORER 4x4
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684 Posts
Ya, looks like it's leaking though it out that vent hole just like mine was. Time for a new one thanks to the damn ethanol.

 
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