[xrad]

I thought I solved the gas smell a few months back when I replaced the filler flex hoses. No more gas smell ,,,,(or was it really gone)



Anyway, after filling the tank or taking hard turns, I have a descent smell of gas. Not overwhelming..but you know it's there.



I removed the filler cover again and checked the filler hoses. No smell.



Got under the car, no smell.



Opened the gas fill outside door, no smell.



But smell is definately strongest inside the cabin at right rear.



I think it is coming from the fume recycling system, but that is a jumble of hoses behind the B pillar passenger side. Maybe a bad one way breather valve? This is the weird part, when I first start the car and move forward, there is a groan (eeeerrrrrriiiiiip) that lasts for 1-2 seconds and comes from the b pillar. Vaccuum problem???



Is there a way to eliminate all that spaghetti?



anyone else experince this???



Any ideas?

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[xrad]

ok..so ichecked all the visable lines in the fill tube area. Unhooked the breather and blocked the hose ends(one to charcoal/condenser and the other from filler neck. Still have gas smell. Worse when windows open as this creates negative cabin pressure. With AC on, no smell. Absolutely no smell from engine bay. fuel lines tight up there....



Might be at the filter or fuel pump as I remember hanging the driveshaft off one of these back when I did the trans......

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[flash]

no signs of "sweating" anywhere? - have you tried "dusting" the suspect area? applying flour or something like that will usually show where a leak is



more than likely it is a hose somewhere - they are all very old, and likely aging out - it takes very little for a leak to result in odor



you could try pressurizing the system to see where the leak is - be very careful not to overdo it though - fuel spraying all over the place is no fun

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[moses]

I had that same problem some time ago. Not finding leaks anywhere else, I figured/assumed/guessed it was coming from the large round collar/clamp that holds down the plate with the fuel lines, in other words the seal between the plate and the neck of the gas tank. I did two things and the smell seems to have gone away, at least mostly. Sadly, I'm not driving so much lately so I can't make an unequivocal claim of success but it certainly hasn't been a problem on my occasional outings.



1. Found gasketing of some kind to go under the threaded collar, or maybe it went under the plate, or both, can't remember for sure. Of course you would like to get it under the plate but life being what it is, that's just plain tricky. I think a Viton or Silicone O-ring might have been involved.

2. I used teflon tape to add some sealing to the threads of the tank neck



I recognize that this was a cludge which at best may have just reduced the gas fumes enough, but I do suspect the seal between the plate and the neck is a weak point (It's pretty hard to get much tightening force on the collar and with the coarse thread there isn't much contact force betw. the plate and the neck) and, as far as I can tell, it's worked well enough. My feeling is that there really should have been an O-ring and a groove for it in the tank neck so the plate has something positive to seal to, but, strangely, Porsche didn't seek my advice on that design.



Thanks for having a problem I can contribute something to, I can finally bump up my postings category a notch <img src="/forum/images/smilies/968/happy.gif" class="smilie" alt="" />

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[LES]

I had a severe case of gas fumes. RS Barn, after checking all the obvious items, discovered that the previous owner had driven six screws into the gas tank when installing a CD player and amp. Now, after installing a used gas tank, everything is fine.

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[rxter]

[quote name='Doc' post='58896' date='Sep 3 2008, 05:01 PM']I had a severe case of gas fumes. RS Barn, after checking all the obvious items, discovered that the previous owner had driven six screws into the gas tank when installing a CD player and amp. Now, after installing a used gas tank, everything is fine.[/quote]



Ouch!! "Gimme that nail gun over thare son, let's put on these purformence paarts"

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[xrad]

1) isolated tank fill and vent lines and sealed both. drove around. smell still there.

2) Undid the gas cap and really strong fume pressure release.

3) reconnected the vent lines. one way valve looked OK.

4) unless the car is moving, no smell

5) I looked closely for holes in the trunk sheet metal and did not find any.

6) no sweating or stains.

7) new tank sender and gasket. no smell under the cover.

8) no smell under the filler hose metal cover.

9) no smell up front at all.

10) smell is just a strong full tank as 1/4 tank



Will check fuel pump/filter lines.....hope it's not the tank. Is there is a line that runs to the far side of the tank???



Thanks for the help.

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[Lonestar968]

I had a VERY similar complaint with my 85 944 many years ago. Upon nearly losing my mind looking for the obvious, I went down. Under the car, that is! I carefully illuminated every inch of fuel line and used an inspection mirror to get a visual on the back side of the lines as well. That's how the culprit was finally found. The lines back by the fuel tank were suspect anyway since that seemed to be where the smell was concentrated so that's where I focused my efforts. One of the lines appeared to have been chafing/rubbing the underside of the chassis, by the fuel tank, for some time. I don't know what may have caused this to happen, perhaps thousands of hours of vibrations.



I took the car to a mechanic who said he bled the pressure from the system and removed the line just to confirm or deny it as suspect. With the line removed and on the bench top it was easy to see the rubbed portion and the teeny tiny little imperfection that was the result. There was also some visible corrosion on the lines in the same, tucked away, area. I imagine that under pressure, the damaged line may have shot out vapor or even a small pencil-stream of fuel in very close proximity to the muffler but it dried up quickly when the ignition was switched off. It's a miracle the car didn't catch fire or blow up.



It should be worth a look anyway. Good luck with this frustrating problem I hope you find it soon.

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[xrad]

lonestar: yeah, that's what I'm talking about! will check for it tomorrow...



Thanks.

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[p65356sc]

Thanks for the info...........I can't run my girl with the top up. My wife sighted it first from the passenger seat. I thought I was alone in this. I had my mech. go through the whole fuel system and nothing. It seemed to be worse when the tank is full.......so I only fill to 3/4 now and it isn't so bad. I thought of the charcoal filter. All it takes, from what I have heard, is to over fill your tank once and you pollute the filter. A friend with a 944 told me he never could solve it in his car. Sounds like a winter investigation job for me.

Thanks

Ross

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[rxter]

My daugther says "Dad I love this car, it smells just like the boat." A combo of the fuel, oil, and Cladosporium sphaerospermum (thanks Kim).

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[xrad]

all I know is that you stated 'blah, blah, blah,...spermum' That is a smell I don't want in my car! <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" />

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[xrad]

Guess what??? Problem solved!!



I drive over to my friend's shop and we start checking every fuel line, vapor line, what we could of the tank, form front to rear and NO leak. Man, it sure smelled on the way over, though! Weird. Must be a hole on the top. But I clearly remember checking for mounting holes BEFORE placing the sound deadener and there were only four into the back of the driver side fold down rear seat from an old bazooka sub.



All lines checked again. The tank held 20 psi pressure without ANY smell or leaks. Also started the car and giggled it around to try to get the smell going while on the lift....NOTHING!!



So then I noticed the engine was running kinda rich because with the car on the lift, the tailpipe was right at our face level. Then I rememberd that I had a loose heatshield so I start looking for it. ALL tight, and I mean really tight.



So then I shake the exhaust and there is the rattle, really bad, coming from the center resonator. I noticed three hoseclamps over three holes. Apparently, these holes at one time held screws which held the inner baffle in place. They were rusted out and missing and we could shake the baffle around by shaking the exhaust. And when the car was running, these three holes were leaking exhaust pretty badly....(So why make an all stainless exhaust and use freeking iron screws to hold the baffle in place?????dumb asses...)



So what to do....hmmm. I took down the rear end of the exhaust. Put it under the band saw and bisected the resonator. out fell the cheese grater baffle and some old screw bits.



I made up an angle iron jig and welded the three holes shut and welded the pipe back together (although I was too lazy to go home and get my argon stainless welder and ended up using my friend's brand new Lincoln steel welder...it has autofill/feed which is really nice..adjusts for gap and arc automatically...does not have stitch, though). ground off some slag and used some high temp paint on the seam.



On the drive home, while enjoying the slightly richer exhaust note, I took some hard turns. Hmmmm , no more gas smell......WHOOHOO!!!



We did not realize at the time that we had solved the problem of the gas smell in the cabin by welding up the exhaust!!!



Now to find out why she is running rich.....O2, mass air sensor... etc.....for another day...



in the pic below, you can see two of the three holes and my new seam. Oh , by the way, this adds 2.3 horse power and she feels SO MUCH faster....just kiddn..

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[Lonestar968]

Amazing. Who woulda' thunk??? Glad you found the pesky problem! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[xrad]

THANKS.



yep..who woulda! Took her out for a 30 min drive last night just to be sure...NO smell!!! <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[flash]

is the factory cat still in there? removing it will make it run rich - aftermarket ones can too - i'm sorting this out right now myself, and am just about to put the factory one back in - the aftermarket ones flow too well and aren't staying hot enough to keep the O2 sensor hot, and between the two of them, i run richer than i want, and fail emissions



p.s. - don't laugh, but you may actually be pretty close on the hp increase - it takes very little backpressure change to see changes in power output

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[xrad]

still has the cat...a big stainless looking thing with about 2.75 inch inner diameter of the rear flange.....





as for my recent thing about running rich:



I cleaned the air mass sensor wire and inner housing and put in a new O2 sensor. that did the trick. For those of you with some basic mechanical skills, it is an easy job. Now, you could spend up to 129$ for the Porsche Bosch O2 sensor (correct length and connector) OR, you could spend 40$ for a 1992 Ford F 250 Bosch 3 wire O2 sensor (#13953...fits a hundred other vehicles from the early 1990's, too) which has the same output and resistance but costs much less. You just have to cut and solder the upper connector to the new O2 sensor. Be careful how you run the wire so that it does not lie over the exhaust. Looked like someone else put another O2 sensor in, but they used a Walker brand. Different end on the sensor, and IMHO, not as well made as the Bosch units. Porsche says every 60,000miles, change out the O2 sensor.



O2 sensors are notorious for not working correctly AND NOT causing a computer fault.....



I put in a 3 wire sensor. This means that one is 12v +, one is signal , and one is ground. 3 wire unit heat the sensor for a faster response. You could use a one wire sensor, but what the hell, go for three. Some sites say that you can switch white wires, and this makes sense since they are resistance based. But when I wired it up, I connected the labeled 1,2,3 from the Porsche connector to respective 1,2,3 locations on the new O2 sensor(meaning that it would be like holding both the connector and the the O2 sensor in your hands with the back ends facing you, and you can see where the wires go, like a triangle with the black wire on top(#1))



Started right up and no warning light. No more rich gas smell either! NO more hesitation on acceleration when cold.



I am very happy to have this baby running nicely!!!

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[ds968]

Looks like it's my turn to figure out a similar probelm ; there's a bit of fuel smell in the cabin when I first get into the car after it's been sitting for a while. The smell goes away in a minute, soon as I start the car and take off. No smell at all in the engine bay, near the fuel lines or anywhere else for that matter. No smell inside of the hatchback area..it stays pretty much to the front of the cabin. No smell outside underneath near the gas tank, under the engine or elsewhere alongside the car in between. No smell whatseover while driving or after turning it off and then waiting to see if the cabin starts to smell up..nothing. Only in the first instance when getting in the car, while it's cold and has been like that for a while... WTF ?! Where do I start looking [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img]

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[prj24149]

DS968 it's been several years now, did you ever solve the smell problem? I now have the same problem. Last week I had my baby in the shop and had them change all the rubber tubings on the gas tank. As well as replace the shift linkage and put in Stuttgart shift block. The shifting is fabulous but the smell is still there in the morning.

Any idea what it is? I was thinking the next thing to look at is the charcoal canister.

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