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Discussion Starter #1
I've been noticing the scent of gas vapor after driving, and yesterday I put my nose to task in the engine bay. I found that a hose had worn from vibrating against another for the past 26 years. Is this just a vapor hose? I'd imagine that if it was fuel delivery it would be spraying out, not just smelling like gas. It goes from the intake assembly across the back of the engine and into the firewall next to the speedo cable.

Question is, is it safe to just cut out the worn part and clamp in a new piece of hose or should I try and find the other end and replace the whole thing? It also wore through the fine Italian fabric of the other line, but not thru the rubber.

Thanks...
 

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The worn hose goes to the heater core. Can't remember if it's the supply or the return hose (believe it's the supply side). The fabric lined hose is a vacuum line for the auxiliary air valve (AAV). I can't see how either hose would be the source of your fuel smell.

On the up side, since the hose isn't leaking I don't think that it's replacement is critical. However, if you do use the heater. Replacing the entire hose wouldn't be a bad idea... even replacement of the worn area could work for quite some time.
 

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There's a good chance that the fuel smell is coming from the trunk area rather than the engine bay (although that's certainly possible). There are a few posts regarding this problem on the Sticky FAQs at the top of this forum.
 

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Discussion Starter #4
Hmm, heater core, that's weird. Is it possible that vapor is coming from the upper hose that bridges the plastic duct to the intake? But yeah, this vapor scent is definitely from the engine bay. I asked my son put his nose near that hose and he said "whoa"! I'll dig around some more tonight...
 

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The injectors are below this hose, and the cold start injector is not far away. If it's leaking, you'll smell it. The fuel rail is there too, and has hoses at both ends that can crack/leak.
Andrew
 

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That hose with the worn spot is absolutely from the heater core. It is a highly molded hose and you will need to buy a new replacement from IAP or Centerline to replace it. No bending universal roll stock in this case. Follow it to it's other end and you will see it disappearing into the firewall near the brake booster. That brass bolt on the center block of the intake plenum is the high point air bleed screw for refiling the cooling system.

Raw gas smells are usually in the trunk, but if you say it is in the engine compartment, then the 37 PSI fuel injection system is surely a likely candidate. I just finished replacing all my injectors with rebuit ones with new hoses. I had my fuel rail chrome plated and replaced most of the other hoses and clamps. After 20 + years, all these hoses have carbonized to the point that they are more like hard plastic rather than rubber. One of the hoses I replaced was dated 3 of 87.

The process I just went through included installing a rebuilt starter and replacing the motor mounts. All the F/I replacements mentioned above, adding a polished cam cover, and new silicon plenum couplers. Took about 3 weeks including waiting for chrome work and new parts, and cost was a little over $400.00.

Robert in Memphis, Tn
 

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Another spot that's in the vicinity and connects to the plenum: the line that comes from the vapor recovery canister in the left wheelwell pocket.

It pulls stink from the tank, and if the hose or can has failed, you get some of that stink drifting around in the engine bay. It would also be a bit of a false air leak, so conventional tricks to find them (remove oil fill cap while idling for example) would be of use.

Still, you're definitely gonna wanna check the actual fuel lines (high pressure feed side, low pressure return side) and injector service hoses first as suggested above as an actual fuel leak is much more potentially dangerous than a cracked vacuum hose could ever be.
 

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Look at the fuel hoses and clamps for sure. Should be 13mm-ish OD rubber hose.
In my time I've had two leaky cold-start injectors, one on a Bosch Spider, one on a BMW 535i. I don't know how common these are, but mine were dumping raw gas down the side of the engine, right by the starter. Potentially very exciting.
Andrew
 

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Discussion Starter #9
Okay, I found it! It's the hose connecting to the back of the fuel rail. The supply line? Anyway, I can remove the washer reservoir and trace this down but I lose it as it bends under or through the firewall. Where is the other end and is it something I can reach w/o removing a multitude of parts?

Thanks.

Oh, by the way, I can rock the fuel rail but I can't see where and if it supposed to bolt on. The center of it looks like it just has a rubber pad on the bottom. Should this be tight?
 

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The other end of the hose connects to a hard line under the car. If memory serves me well, the supply line is only about 18" long. The top of the hose should connect to the fuel rail via a fuel line clamp. If there is a loose clamp (or it's gone), you have found your issue.
 

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Oh, by the way, I can rock the fuel rail but I can't see where and if it supposed to bolt on. The center of it looks like it just has a rubber pad on the bottom. Should this be tight?
The fuel rail is supported by a part that looks like the one below. It is positioned between the bracket on the lower part of the fuel rail and the plenum-support bracket, which is shaped like a "7" and extends from the motor mount to the lower side of the intake plenum and then to the bottom center of the intake manifold. If this part is properly installed, the fuel rail will not have much play at the center, but the ends will easily move vertically a bit as the rail can pivot on this rubber part.

 

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Discussion Starter #12
Okay, cool. There is a clamp and it feels tight and it's not wet or slimy at the end of the hose, but it's slimy under the clamp so I suspect a crack right under the clamp. I'm looking but I can find a description of this line. I assume putting the car on ramps I'll be able to reach the other end? And does anyone know the mm size of it so I can order it?

Thanks much.
 

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Discussion Starter #13
Thanks sloboy, yeah it rocks on each end so then it should be okay.
 

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8 mm is extremely close to 5/16 in., so you could get a piece of 5/16 fuel hose locally and see if it solves the problem. If it does and you want the true 8 mm hose, you could order it and then replace the 5/16 hose.
 

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I replaced my supply and return fuel hoses with 5/16" tubing from the local car parts place. Has worked well for over a year.
 

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Discussion Starter #17
8mm or 5/16, got it. Check this out... Here's a picture under where the hose connects. - it's the one on the right The screw side of the clamp is jammed tight against the frame! How (why) could they do that? Guess I'll have to pry the sides holding the nut away and hope I can turn it with an open ended wrench.
 

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If you cut the hose, you may be able to twist the clamp around to a point where you can access the screw head (especially if the rubber is damaged as you suggest), but obviously, if it is really stuck on the rigid tube, you don't want to damage that tube.
 

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You want to get 'fuel injection hose' not just 'fuel hose' to handle the higher pressures.

It is sometimes harder to find 5/16 fuel injection hose at the local places which is probably why ended up just ordering the 8mm stuff.
 
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