pcar928fan

Guys,

My S4 and '92 GTS are both smelling of gas. Had the '92 up on the lift yesterday and it was diagnosed as "over burdened" and "used up" carbon canisters. My guess is that there is actually more like a slight blockage in the return line causing a bit of a back up. Only smells when it is running and mostly smells at the back of the car.

So, my question (for both cars...I think it is a broken "Y" pipe on the S4, but have not confirmed that yet) is can the Carbon Canisters be eliminated and the in line and out line just be tied together to delete them???

SeanR

Just replace the Y and you will be good.

fraggle

I'll bet on cracked fittings - replace the Y and the smell will go away. Nicole has one made of metal or you can made your own out of brass plumbing parts. I wouldn't remove them in case your state ends up with some crazy overzealous emissions inspector.

SeanR

+1 on the steel Y that nicole carries. Never have to worry about the plastic one breaking.

fbarnhill

Hi guys,
A smell of gas in the cabin was what started me on my journey that ended in my engine fire. It was the smell of old gas. So I replaced all fuel lines, dampers etc... I had started the car and it ran great, I turned it off and noticed something running down from the passenger side under the engine, The next thing I knew, I was surrounded by fire. At first I thought I left the line loose on the retulator on that side but I have checked and all fittings are tight. The lines are gone but the fittings are tight. There was a big scourch mark on the floor directly under the charcole canister. My only theory was that when the regulator and dampers went bad, gas was somehow sucked into the canister. I had checked the Y on mine and it was not broken so I didn't replace it. Now I wish I had replaced the whole thing.

Best of luck and please, don't take any chances with that gas smell. It only took a nanosecond for this thing to go.

Thanks,

BPG_Austin

Porken deleted his canisters and vented the line. There's a thread on it somewhere in the archives.

SanDiego928

FYI - My recent gas smell in the cabin and when opening the windows was from 2 gas leaks - 1 at fuel pump and other at top of tank, old hose and 1 copper washer gone bad. I was thinking of checking and will check the canister after reading this thread. Thanks. For now, I have just a fresh smell of old leather, carpet and God only knows what else is under those seats making some of those strange odors.

SeanR

Here's one thing to consider when thinking of pulling out some of the equipment.

Greg B made a comment about the tank ventilation system, and how if it's not operating right, the tank can actually get sucked flat, which would lead to a number of issues. One of the most important things is to ensure the fuel system (that's everything from the supply/return to the vent system) is 100%.

dr bob

The carbon in the canister never "wears out". It's a sponge for fuel vapors only, never sees liquid at all. It only needs to sponge when the car is not under load. Plus it's a closed system, with the only vent to the intake and that's only open when there's enough engine load to open the vent vacuum solenoid. There is nothing to be gained as far as performance by disconnecting the carbon canister. There is a lot to lose. First off, the vapor that escapes comes from somewhere, and that's liquid fuel that's slowly flashing off. The vapor concentration in the canister and vent lines is 100% saturated, so it certainly has a potential for causing a fire or explosion. Raw fuel or even saturated vapor will flash as soon as it contacts a hot exhaust manifold-- it doesn't need a spark! Parked in the garage, the vapor is relatively heavy, so it hugs the floor and finds an ignition source that might look like a gas water heater, furnace or clothes dryer.

The factory Y piece is under $10 from our regular 928 parts suppliers. Installed correctly with the hoses all supported, it should last the life of the car. The original installation allows the hoses to move and stress the connector, sometimes causing it to break. Nicole's metal replacement is a good option, in that it removes all possibility of another fracture.
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The 928 project here last week was intake and cam cover refresh, with Rob Edwards' help and guidance. Part of his procedure includes jumpering the fuel pump relay before the air cleaner housing goes on. Full pressure in the system let us identify a very slight leak at a connection to the rear fuel damper. So slight was the leak that I may not not have noticed the fragrance in the garage, and certainly not while driving. The only way I found it on the car was by feeling all the connections and then sniffing the probing fingers. That one wasn't really wet, but the hint of gas smell on my fingers was enough to get our attention. It was a bomb waiting to go off. I subsequently fixed the leaking connection, and all is well once again.

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Got original fuel hoses? Like living on the edge? Park the car in the attached garage, under the kids' bedrooms? Fire insurance paid up? Just checking your sanity. There's no such thing as a small fuel leak, and there's no such thing as a small gasoline-supported house fire.

worf928

+ 928 x 10^928

I always, always, always, do the above. And, I too, have caught small leaks. Regardless of whether you've got new fuel lines, always do the pressurized leak test with the FP relay bypassed. The injector o-rings can leak if you've just put in the rails and/or you might not have tightened-down one of the line couplings enough.

Fuel leaks are no joke.

vsalvato

Guys, I suspect that my S4/MY88 carbon canister was removed by the former owner (I own the car since three years but admittedly I never checked if the carbon canister is still there. I smell gas vapour when the car is running and the windows and/or the sun roof open and this led me to believe that the carbon canister is not there any more. Assuming that this is the case how expensive and difficult is to restore the whole vapors recycle circuit and the carbon canister?

pcar928fan

Probably just cracked lines to the carbon canister...that is the common problem. My lines were not cracked so we replaced the canisters in the GTS, but I suspect the lines in the S4. Doubt anyone would remove the canisters and just taking them out and connecting the lines would not cause a gas smell anyway.

NC928S4

A couple of threads back many of us were talking about Y-Connector issues. I had a faint gas smell and had changed fuels line 9 months prior so I heeded all advice and triple checked the fuel lines which were all okay but did find cracked Y-Connector. I made the repair but, sadly the fumes continued so I checked fuel lines again and tweaked hose clamps slightly just to be sure.

My faint fumes continued and this thread had me check fumes near the rear rear end. A simple sniff test around gas cap has a strong gas smell with fuel door closed. Based on the pictures posted so far my cap looks fine(no cracks), both rubber gaskets in place and yet odor is strong right at the door. The gasket/ring around filler tube is definitely not very pliable(seems to have hardened with age).

Is a less than pliable filler tube gasket/ring the culprit?

Asiandude

A slightly different cause of this on my car ('87 S4) turned out to be a cracked fuel vapour "compensating" tank located up inside the right rear wheel well. It's a long plastic tank and had cracked in a few places - old age I guess. I made a replacement out of an aluminium water bottle as a temporary repair.

vsalvato

Guys, is the carbon canister located above the rear right wheel arch? I suppose that it is detectable only by removing the wheel? I know I should search related threads but maybe that I can get a quick confirmation by this. Any picture showing the exact location of the canister?