marky522

I have a similar issue, I know for a fact my carbon canister is bad because i am getting fumes out the vent on the drivers side (smoked entire system) so i will be removing that to see if it helps. I plan on using a check valve on the vent line that comes off the tank and used to run to the charcoal cansiter to allow air in, but not allow fumes out.

Mark

KLR

FWIW, try removing the fuel vapor purge valve and blowing through or sucking on the vacuum port. Mine was bad and it caused a variety of funky symptoms, including an occasional fuel smell in the cockpit when the car was driven aggressively. Other symptoms were gurgling noises in the vent lines near the tank and pressure equalization in the gas tank when the cap was removed immediately after driving the car hard.

T_Glass_27

LOOK AT YOUR GAS CAP! I delt with this forever and couldnt figure it out. My gas cap wasnt sealing good so after I filled up and made a hard left turn gas would come out the gas cap and go down the overfill drain making the car smell like gas. I finally figured it out on a track day because after so many right turns gas was literally dripping down my paint from the gas door. I have a locking gas cap on it so I am gonna go back to the original gas cap.

Joliett

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FWIW, try removing the fuel vapor purge valve and blowing through or sucking on the vacuum port. Mine was bad and it caused a variety of funky symptoms, including an occasional fuel smell in the cockpit when the car was driven aggressively. Other symptoms were gurgling noises in the vent lines near the tank and pressure equalization in the gas tank when the cap was removed immediately after driving the car hard.
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I agree - this fixed my 83 YEARS AGO - and never had the problem again...untill my 1987 started doing the same gas smell thing. BUT, no pressure buildup in the gas tank this time. Catalytic converter is about to get changed anyway...see what happens....

River

Also (And I think that charcoal canisters and cracked fuel lines, and tanks are good picks too)

Check first:

Rear hatch seal (Does it touch end to end? If not, replace...reseal with 3m)
Upper hatch seal (cracked, bad, leak, replace)

Still smell?

Check all your door rubber and sunroof

Still smell?

Pull your hatch area carpet and check your fuel sender and cap for leaks

Still smell?

Plug wire. Hell, prolly time for a good tune up (this cured my smell by 70%) especially with the plug wire part

Still smell?

Injectors. My cure all. Do the rebuilt thing yourself, or send them into your fav place and have them cleaned with all new caps and rings. (make sure you use oil or atf before you shove everything back in).
(this was the finale of my fuel smell).

If you did do the above, make sure to check for a gas smell in the oil cap. If you do, flush your system. (cheap oil, and a can of seafoam). Shove it all in there to make it 7 quarts, and go drive the whizz outta that car for 50-100 miles. Come back, do a full service change (filter and oil).

Also check fuel lines too, fpr, vacuum lines. (run seafoam through vac lines too).

Took me awhile, but it was worth it. Zero gas smells! Yay!

ABCar

I pulled the cap over the fuel sender unit and smelled strong gas but saw no liquid on the top or garage floor. Could it still be the seal on the top of the tank or is it more likely one of the hoses coming from the cap at the top of gas tank? No smell in vents or engine bay so it seems like something in close proximity to the tank in rear. It also doesn't matter if the tank is full or not, driving style either. I want to start with the simpliest things first...

fittrjoe

New gas cap solved my gas smell... not the locking type either ... i think the one i ended up using is for a 911 , the o-ring is real stout... I also agree to never fill more than 3/4. I tried everything and it was the stinking original locking style gas cap the whole time... bad seal

1990 944 s2

Taimyshu

The gas smell in my car was due to a bad seal on the fuel sender unit and some worn out hoses and loose clamps that went to the fuel sender unit.

mytrplseven

Good stuff to tuck away for the "eventuality" when it does happen to me.

Tedro951

Agree with all of the above, but add taillights, as crazy as that sounds. When I reinstalled them with new sealer the smell went away.

River

Dude, totally not crazy. Can't believe I left that one out too! LOL!

I think 944online has the new seals now too...

I just scraped what was left from mine and used black silicone and shoved the damn light in. I was more worried about leaks then the smell at the time. Maybe I got a two fer?

Tedro951

Yeah, I went nuts with the ribbon sealer....the next owner will probably have to replace the rear clip to change out those lenses!

944geek

Hi all, this, as you have figured out, is a problem common to early 944s caused by cracking in the top of the tank, it is a design flaw.

I have removed my tank and sanded back the metal and fibreglassed the damaged area which seemed to do the job.

If you don't want to go to the hassle of removing your transmission to fix the tank this way, I have a workaround solution.

I have connected a T piece into the tank vent line where it comes up along the firewall (LHS of the engine bay) and run it to the intake cold air snorkel.

It is just 10mm (3/8) radiator overflow hose connected to a small brass right angle fitting (thin walled brass plumbing connector) which is connected to the intake air snorkel. It does permanently what the Idle Aux Air valve does when your engine is cold. It draws off the fumes into the intake system.

If you are concerned about letting air enter the tank as the fumes are drawn off while you are driving, you can drill a 1.5-2mm hole in the underside of the vented fuel cap.

The other thing to remember is not to fill your car past 3/4 or the fuel will leak out of the top of the tank and run down by the muffler and then you are smelling raw fuel not just fumes that are venting!

If you want more specific instructions, just email me at 944geek@gmail.com

Cheers
David
Brisbane Australia.

Tiger03447

If you have to do a tank repair, I used a hand vacuum pump and brought the pressure down inside the tank..Took a while to get a reading, because it's a pretty good sized tank to pull down. Mine held the vacuum quite well, and after several minutes, I released the vacuum. You can do the same with an air compressor too, just watch a pretty sensitive gauge for awhile after pressurizing the tank to check for leakdown..and pressure drop.

black944 turbo

I am dealing with a similar issue, when my tank is very low it does not smell or if it sits for a week or two no smell. But it stinks after a drive both inside and in the garage. I have not seen any visual evidence of a leak anywhere. Any suggestions of where to start? I am going to pull the sender this weekend to check the seal. It is definitely coming from the back of the car.