[84 Carrera] Fuel-ish smell inside the car?

[Arne2]

I thought about posting to daniel911t's thread, but I don't think we have the same exact problem, so I figured I'd start a separate thread.

My car ('84 Carrera Coupe) has no fuel smell at all in the garage, in the front trunk, under the front of the car, or in the engine compartment.

But—if I let the car sit overnight with the windows up, there is a sweet-ish smell of hydrocarbons inside the car. It does NOT smell of raw fuel, but reminds me of the odor if the volatiles in the fuel are seeping through a fuel line somewhere.

I know there are fuel lines that run through the tunnel, but how permeable are they, even if they are old? And if I need to replace those lines in the tunnel, I'm having trouble identifying those particular lines. Does anyone have a diagram that shows all the lines and where they run?

[Arne2]

No comments or ideas?

[robhamster]

I have an '84 and that smell thing happened starting about 2006. It progressively got worse. Last year when I had a wrench doing some work on the engine and tranny, he checked the fuel lines and found the supply line in the tunnel cracked and leaking ever so slightly. Changing out both the supply and return line made the smell go away. It took about 8 months before I could get in the car and not smell fuel. It had leaked all throughout the pan.

Check the plastic plugs under the car along the tunnel to see if you can find evidence of gas leaking. Where I saw evidence was under the front of the tunnel.

[BoxsterGT]

Wow, this is the first indication I have heard of a Polyamid line failing inside the tunnel. I wonder if anyone else has seen this.

I thought these latest black plastic lines were the only way to go. I would use them much more often, but the fittings are a SOB to install & they are a one-time only install. The only way to remove the fittings is to cut back the tube verrrrry carefully, and then the tube is too short.

I should rethink using flared SS tubes thru the tunnel instead.

Any chance this line was disturbed by some repair of the shifter or clutch cable or some such work in the tunnel?

Do you know where inside the tunnel it occured?

Len

[dshepp806]

Usually it's the lines entering the tunnel (external to, that is).

I'm currious as to "where" IN the tunnel, also.

Best,


Doyle

[wearl]

i had that problem and the fuel pump body was leaking on tray under fuel pump. i could smell in garage and car, could not figue out where smell coming from. thought it was my mower. had car on my lift to change gear oil and my brother in law saw 1 drip coming from tray under pump

[CCM911]

Funny. I also have a 1984 and have the same smell in the interior. But no gas smell in the garage.

Can you shine a light into the tunnel to find a leak? Or if there is a leak, would I see moisture by the shift coupler?

[tirwin]

Arne2,

I have been posting questions about fuel lines recently. My general concern is that the ethanol content in modern fuels can do some damage to our old fuel lines. Age plus accelerated breakdown of the fuel lines is not a good combination IMHO.

A few companies make SS braided lines and the interior is coated with Teflon which is resistant to ethanol. My opinion is if I'm going to spend my time and money on my dream car, why risk a fuel fire? Therefore, I plan on replacing mine with something I don't have to think about for another 30 years.

What I don't know about is the polyamid lines. I don't know anything about their longevity or susceptibility to ethanol. I'm at the point where I'm thinking of just replacing them with SS lines just for peace of mind. Again, why risk it?

Be aware that getting the fittings figured out is a little challenge. I'm working on that right now. I'll post my findings.

[wearl]

the smell in garage was very faint. i have a garage with 2 sections. when in the front section with door being used all the time and left open you could not smell. but in rear section where i have my lift and lawn mowers gas etc., when car sat for a while you could smell after a couple days. i was checking my gas cans, mowers etc.

[Arne2]

OK, I plan to pull the console in a few days to install a new shift boot, so I will pull the shift tower and rear access plate and look at the tunnel lines as close as I can at that time.

Assuming that I need to replace these lines, how high on the 'ugliness' scale does this job sit? And does anyone have part numbers of the lines I'd need?

[p911dad]

this is the area where it is common to have a fuel leak. the rubber line from the pressure side of the pump (red in the illustration) to the point of its junction with the hard plastic tunnel line is where I had the problem. The rubber got dried out and cracked, allowing fuel to weep out. It is a pain to replace correctly (meaning with a whole new line from pump to engine.) Our host carries these parts.

[BoxsterGT]

FYI - I just sent out the first of what I hope will be a permanent fix for this issue. I am now making up the same Black Polyamid fuel lines for the tunnel as the original but with one exception.............



They have M14x1.5 Male fittings at each end. They allow an easy replacement of hoses in the future, and also allow flexibility in changing or relocating the fuel pump. For those planning on a 3.6 upgrade, I also have these tunnel lines with M16x1.5 Male fittings to match the larger dia factory hoses & lines used presently in all current Porsche models.

I also make up correct Metric fuel hoses as original replacements or for any custom configuration you may need. This includes all 911 and most 928 and 944 models.

For more information & pricing, pick my user name & send me an email. Please DO NOT PM me. My box is almost always full and I cannot send photos or track messages by PM.

Thanks,

Len at Autosportengineering dot com

[88911coupe]

Len, that looks awesome and a great solution! Regarding the OP, I had a similar situation after I replaced the rubber lines into and out of the fuel pump by the tank. I would get a faint fuelish smell in the morning if the windows were all closed. I determined that the line to the canister in left front wheel well was cracked where it connected. I just cut off the end and reconnected it and it seems like the problem is solved. I think a better solution would be to just put a new line there since the original is pretty old.

[Arne2]

Originally Posted by 88911coupe

Len, that looks awesome and a great solution! Regarding the OP, I had a similar situation after I replaced the rubber lines into and out of the fuel pump by the tank. I would get a faint fuelish smell in the morning if the windows were all closed. I determined that the line to the canister in left front wheel well was cracked where it connected. I just cut off the end and reconnected it and it seems like the problem is solved. I think a better solution would be to just put a new line there since the original is pretty old.

After reading this, I took a look under the hood in mine. I had earlier determined (by digging through all the receipts and service records) that all the fuel lines on my car were replaced when the top end was done 40k ago. So not new, but not 29 years old either.

But after checking, all the vent and evap hoses were obviously still original. I changed them Saturday, and left the car closed up until this evening. No smell. The vent hoses were indeed the issue. Many thanks to 88911coupe for the idea.

[rusnak]

Gas smell inside the car is usually the fuel lines inside the tunnel. You would usually smell a stronger odor inside the trunk when the vent lines are bad. Also, the gas sending unit gasket can go bad, and let vapor collect inside the trunk. Since the tunnel lines are NOT fun or easy to replace, you always check the easy stuff first. Glad that you seem to have it fixed!!!