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Interesting Fuel leak issue. Thoughts?

 
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killerbeem



Joined: 01 Aug 2005
Posts: 496
Location: Detroit, MI

PostPosted: Sat Nov 12, 2011 3:34 pm    Post subject: Interesting Fuel leak issue. Thoughts? Reply with quote

OK, so I am looking for suggestions on how best to determine where a fuel leak is occurring.

Here's how it started:
1. Every time I fill up my tank to full and then I park in the garage, the next time I return to the garage, I can definitely smell fuel. Initially, I thought it was because the cap wasn't on tight, so I verified.
2. I crawled under the car, without jacking it up, could not see fuel leaking under the tank, so I decided to start from the front and work my way back.
3. I jacked the car up, following the fuel lines directly into the injectors, and could not find any wet spots (other than normal "oil dirt"), so I cleaned the area, and let the car sit.
4. Over night, the smell grew stronger, and there was no fuel leaking around the fuel lines under the car either.
5. Then, I backed the car out of the garage, and found the tell tale signs of a fuel leak, and it was centered around where the fuel tank fill hose is. 6. Well, not being able to determine exactly where yet (my tank over the course of three days, and two drives to test out other minor work I was doing (belts, plugs, oil change, etc) was down to just over 1/2 a tank but under 3/4, and wala! no fuel leaking after the car sat for 36 hours.
7. So I took pictures. See them below. What I THINK is the sign of a fuel leak is evident by discoloration, but I am not 100% sure, so I wanted to bring it to everyone here so that I can get a group response.


Ultimately, the issue is, anything over 3/4 a tank will result in fuel leaking from one of two areas, either the fuel fill hose, or on the other side were the fuel lines attach, I have also taken pictures of that area.

I am searching the web and this site to see if this is somewhere common, and I definitely have no issue replacing hose lines, fuel pipe, etc; but not REALLY looking forward to dropping the gas tank, based on what I have seen under the car on how to get to it.


Here are the pictures:

https://picasaweb.google.com/mkilpatric/BMWFuelLeak?authuser=0&feat=directlink
_________________
Currently looking for a good e30 to rebuild
1994 318i - Jeni (sold)
1991 325i - Lynn (Sold)
1984 325e - Rachel (Sold)
BMWCCA Member
Find me on Twitter: @mkilpatric
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geminiys



Joined: 13 Oct 2004
Posts: 182
Location: SF, California

PostPosted: Sat Nov 12, 2011 6:41 pm    Post subject: Reply with quote

I recommend removing the rear passenger tire and then removing tire well rear splash guard, holding on 3 screws, if I remember correctly. You will be exposed to more hoses that interconnect fuel tank, charcoal canister (sits under the spare tire cover, and pressure sensor. Look in there, as that is the area where hoses bent a lot and crack over time. Mine was badly cracked but only gave me "Check Engine" and Small Leak Code through OBD-2 scanner. No small of gas. Again, my car is OBD-2. Not sure about yours.
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PJK



Joined: 14 Feb 2002
Posts: 1829
Location: Shingle Springs, CA

PostPosted: Thu Nov 17, 2011 2:25 pm    Post subject: Re: Interesting Fuel leak issue. Thoughts? Reply with quote

I had the same issue a few months back. It was the gaskets for the fuel pump / fuel gauge senders.

You can access them by removing the rear seat cushion, then the two metal access plates under it. Before removing the senders from the tank clean the area with a vacuum cleaner or compressed air.

When installing the new gaskets spray them with silicone mold release spray to make it easier to install.

I believe the procedure is in Bentley and Pelican has the parts.

Phil

killerbeem wrote:
OK, so I am looking for suggestions on how best to determine where a fuel leak is occurring.

Here's how it started:
1. Every time I fill up my tank to full and then I park in the garage, the next time I return to the garage, I can definitely smell fuel. Initially, I thought it was because the cap wasn't on tight, so I verified.
2. I crawled under the car, without jacking it up, could not see fuel leaking under the tank, so I decided to start from the front and work my way back.
3. I jacked the car up, following the fuel lines directly into the injectors, and could not find any wet spots (other than normal "oil dirt"), so I cleaned the area, and let the car sit.
4. Over night, the smell grew stronger, and there was no fuel leaking around the fuel lines under the car either.
5. Then, I backed the car out of the garage, and found the tell tale signs of a fuel leak, and it was centered around where the fuel tank fill hose is. 6. Well, not being able to determine exactly where yet (my tank over the course of three days, and two drives to test out other minor work I was doing (belts, plugs, oil change, etc) was down to just over 1/2 a tank but under 3/4, and wala! no fuel leaking after the car sat for 36 hours.
7. So I took pictures. See them below. What I THINK is the sign of a fuel leak is evident by discoloration, but I am not 100% sure, so I wanted to bring it to everyone here so that I can get a group response.


Ultimately, the issue is, anything over 3/4 a tank will result in fuel leaking from one of two areas, either the fuel fill hose, or on the other side were the fuel lines attach, I have also taken pictures of that area.

I am searching the web and this site to see if this is somewhere common, and I definitely have no issue replacing hose lines, fuel pipe, etc; but not REALLY looking forward to dropping the gas tank, based on what I have seen under the car on how to get to it.


Here are the pictures:

https://picasaweb.google.com/mkilpatric/BMWFuelLeak?authuser=0&feat=directlink
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killerbeem



Joined: 01 Aug 2005
Posts: 496
Location: Detroit, MI

PostPosted: Wed Nov 23, 2011 5:45 pm    Post subject: Reply with quote

Guys,

Thanks for the insight. I am pretty sure at the point the seals are my culprit, and have ordered them (patiently waiting...)

I'll update the outcome once I am completed.

MK
_________________
Currently looking for a good e30 to rebuild
1994 318i - Jeni (sold)
1991 325i - Lynn (Sold)
1984 325e - Rachel (Sold)
BMWCCA Member
Find me on Twitter: @mkilpatric
Back to top
View user's profile Send private message Send e-mail Yahoo Messenger MSN Messenger
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