Weird Fuel Leak... Somewhere...

[FastWoman]

Yeah, I know the problem didn't go away!  But at least I have an extinguisher now.  Hopefully the clamp tightening does the trick.

 

I, too, was thinking of the carbon canister.  However, that wasn't the area where I smelled the fuel ,with the car sitting in the garage.  Also the tank was less than half full, and I wasn't doing any spirited driving.  I'm starting to entertain rossiz's theory!

 

Rossiz, I did wiggle hoses, but the hoses between the rail and injectors didn't really have much room for wiggle.  They're pretty much barb-to-barb.

 

I'll be back on the road again, once I bring my jack and stands back over from another house.  I'll be snugging up fuel clamps everywhere (and replacing my prefilter while I'm at it).

[FastWoman]

Well, another night of sitting, and again rock-solid stability in fuel pressure.  I started up again, watched, wiggled hoses, sniffed, watched, tweaked the idle, cleaned some dust, waited, sniffed, wiggled.... NADA!

 

So I tightened all the hose clamps.  They felt pretty snug already, except for one.  The clamp at the top of my fuel filter was a bit looser than the others.  I saw no residues on top of the filter, and that wasn't where I was smelling gas anyway.

 

Anyway, I've got some basic tools, a flashlight, and an extinguisher loaded up.  I'm off to the grocery store.  Wish me luck! 

[FastWoman]

I'm back.  Car didn't catch on fire.  No drips.  No gas fumes.  I drove the car pretty hard.  [shrug]

 

I guess it's fixed, but I'm still carrying the extinguisher.

[Zed Head]

When my old injector hoses failed they cracked lengthwise internally.  I smelled gas, stopped and opened the hood, and a very thin stream of fuel squirted out on to the sidewalk.  A tightening with a screwdriver got me home, but that fuel traveled quite a way from its origin.

[FastWoman]

Thanks, Zed.  But you're talking about old, dry-rotted hoses, right?  Mine are new'ish and supple.  Or can new'ish hoses split under the right conditions?

[Zed Head]

More likely that the inner lining would get damaged during installation.  They're multilayer.  But you already knew that.  I was just pointing out the possibility of the leak starting in a not obvious location.

 

Another thought is one of the fittings on your fuel rail.  Brass fittings in aluminum might loosen a little over many heat cycles.

 

Just brainstorming...

[FastWoman]

Hmmmmm....  I did use some of that blue rubber-lined FI hose at some point, but I concluded it was pretty fragile and didn't hold up well to repeated removal and reinstallation of hoses (e.g. for the fuel filter).  So I switched to the solid black kind (no blue rubber lining), which seems to be sturdier.  I'm pretty sure I used that type for connecting my injectors.  But yes, I'll have a closer look to see whether I have any of that blue-walled stuff still in the engine compartment.  I could see it delaminating (as it has done before on me) and leaking.  Good thought!

 

I'm skeptical about the leak being from any hard parts, as I would think that would result in a consistent leak, not an intermittent one.  I could be wrong, though.  From what you write, it appears you remember my having an extruded aluminum fuel rail with brass nipples; however, I have the stock brazed, 1-piece "trumpet."   The only dissimilar metals would be in the injectors themselves.

[Zed Head]

Actually, I was almost remembering the wrapped rail.  That's what it was.  Wrong "not stock" memory.

 

Maybe your FPR got stuck and overpressurized the rail for a moment.  Although, having taken an FPR apart, I'm not sure how that could happen.

 

Good luck.  I hate the smell of raw gas.

[Captain Obvious]

Even if the FPR got completely stuck shut on the outlet, the pressure in the system should have only gone up to the dead head pressure of the fuel pump and the system still shouldn't leak even at that pressure.

 

So keep the fire extinguisher handy, keep a keen nose, and good luck with the hunt. You know it'll be back.

 

Most likely you'll be dressed nice, it'll be raining, and you'll already be late. My friend Murphy works on these kinds of problems all the time.

[rossiz]

yes, and you'll more than likely have a teenager in the car who will roll their eyes and shrink below the window sill, mortified that one of their friends might recognize them in a (gasp!) "old car"...

 

but we'll be here for ya!

[FastWoman]

Well, I've traditionally taken the longer road trips in the Z, but I think this holiday season my car of choice will be the Saturn.  I figure I'll keep the Z to just stop-and-go traffic for a while, the reason being that I can only smell the leak when at a dead halt.

 

Fortunately I don't suffer from any family members with mortified teenager syndrome anymore.  My kids are in their mid 20's now, and they appreciate the old classics.  That wasn't true back when I bought my (very cool) '66 Mustang.  (It was noisy, and the exhaust stank.)

 

Thanks for all your help, guys!

 

Sarah