Does braided lines off gas?

[GTSnake]

Ever since I changed my fuel system I've smelled gas in the garage. It's strongest after I've driven the car. I've looked and looked everywhere and couldn't find one drop of liquid anywhere. I've checked the fill tube and it's fine. I've checked every joint and connection there's nothing leaking. When the car sits over the winter the smell goes away but in the spring when I fire it up the smell comes back.

The reason why i suspect it's the lines is because when I put my nose right up to it I can smell gas. At any point in the system if I smell the fittings and lines I can smell gas. But there's no liquid anywhere. I have to believe the lines are rated for fuel and shouldn't be a problem so then why do I smell the gas?

Is it just a consequence of having braided lines or is there something wrong? It's getting really annoying.

 

[PSilverGTS]

I had a 300ZX TT and had a gas smell. Turned out to just be a loose clamp. The gas was sweating out the end. The oder was strong even though it was not even a leak. You could also check your charcoal canster (also a filter in it) to make sure it is working properly.

 

[Bob D]

I've noticed the same thing since I did the fuel system last winter.

 

[Camfab]

Braided steel lines are not lifetime hoses as some may believe. Some of the hose your buying may have sat around for years. I had a full length of -8 stainless line go bad in the past. It was on the suction side of the pump, in fact it was so bad that I thought the fuel pump had failed. After racking my brain as to why I had no fuel pressure, I removed the line and capped on end. I pressurized the other end and placed the whole hose in a tank of water, the entire hose looked like a fish tank bubbler.

 

[GTSnake]

My charcoal canister is not even hooked up. When I replaced my fuel system I completely bypassed that.

So does that mean I have old hoses? Why isn't there any puddles of gas oozing out then? They cost a fortune to install and now I have to replace them all?

 

[GTS Dean]

I have a buddy with a custom fuel system on his TT '99. It actually started leaking puddles of fuel on the floor of his garage. The hose liner appeared to be disintegrating due to incompatibility with current pump fuels.

I have just reviewed my handy Aeroquip master hose catalog for Gasoline Service. Here are the liner material recommendations:

EPDM - Unsatisfactory
Synthetic Rubber - Conditional
Teflon - Excellent
Thermoplastic Elastomer - Excellent
AQP - Excellent

My guess is that a lot of people are probably using a synthetic rubber liner and having deterioration problems. If you kink the hose during installation, or have too tight a bend radius (especially on the suction side) you can experience early hose failure that is not readily discernable. You can learn a lot by reading a book.

 

[Steve-Indy]

...what Dean said...but, beware...some of the "earlier"Teflon liners used inside the braided hoses DID LEAK under high flow states due to pinholes created by static discharge (and caused car fires in a race application). It seems to me that the "fix" was to use carbon in the teflon...but my memory is a little vague on that aspect.

 

[Steve-Indy]

here is a link to some old patent info as it telates to teflon and static charge with fuel flow...note the use of carbon black:

http://www.google.com/patents?id=Eh...=static+in+teflon+hoses&ie=ISO-8859-1#PPA1,M1

 

[GTSnake]

Crap! That means that I'm going to have to replace all my lines

 

[GTS Dean]

If you have reuseable fittings, it's really not that much trouble.

 

[GTSnake]

If you have reuseable fittings, it's really not that much trouble.

Sure it's not that bad changing the lines but getting them out and back in is the PITA. Looks like a winter project.

 

[klamathpro]

Try hooking up the charcoal canister again. It's supposed to get rid of the fuel smell caused by excess vapors in the return line.

 

[GTSnake]

Try hooking up the charcoal canister again. It's supposed to get rid of the fuel smell caused by excess vapors in the return line.

I'm not sure I can. I would have to reduce my lines from a -8 down to the stock size.

 

[GTSnake]

Just an update of what I discovered. I called a guy from Aeroquip today and he told me that braided lines WILL vent. It is very normal for them to do this. There isn't any fluid leakage but some gas vapors can escape. If you get the teflon lined lines it shouldn't vent at all.

Looks like I'll be replacing my lines one section at a time over the winter. BTW my fittings aren't reuseable either so there's another $500 bucks.

 

[FE 065]

Well, the outer braiding is just an external feature isn't it? Any leakage would have to come through the inner liner material first..meaning the inner liner is deteriorating..(?!)

http://www.bonacoinc.com/braided_hose.htm

 

[GTSnake]

I'm not sure the lining is deteriorating. It's smelled since day one. Plus the lines are only two years old. The Aeroquip guy said it's because of the type of lining. If I had the teflon lined inner the vapors would not leak out.

 

[GTS Dean]

BTW my fittings aren't reuseable either so there's another $500 bucks.

With the exception of teflon, the cost of the hose itself is ~20% of the cost of an assembly. It makes no sense to me to spend money on anodized aluminum end fittings if they aren't reuseable. Aeroquip only sells steel & brass fittings for teflon hose, and the reusable ends (3-pc) are quite a bit more complicated to assemble.

 

[Hisserman]

What a pain, Tom.

 

[Silver_Snake]

Just my humble opinion, but......... properly installed hoses in good condition of the correct material, fittings, tightning, etc. will not "sweat", "leak", "breathe", or otherwise release fugitive emissions. For liquid hydrocarbons the best hose material is neoprene, the steel braiding is merely reenforcement against internal expansion (induced pressure, vapor pressure due to temp, etc.) and external damage or severe bend prevention / protection. All hoses have a service life, and will deteriorate and eventually fail. Seepage resulting in odor is the first sign (absent fitting problems) the hose is of an incompatible material, inadequate pressure rating, or simply failing due to deterioration due to age / service.

 

[GTS Dean]

Please see post #6.

Thank you.

 

[GTSnake]

So it looks like I'm going to replace them at a moderate pace. However if I start seeing little puddles then of course the pace speeds up quite a bit.