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I have just discovered that my 90 C2 has a fuel leak around the neck of the fuel filler.I have read a few posts relating to this problem.Was it unique to 964's or to all 911's ? Will the fix be covered by Porsche ? and how common is the problem ?
Had same thing. Not covered by porsche. New neck solves problem. Lots of people had this same problem. It is because when you fill car with gas, the weight of filler handle starts to warp filler neck. When filling with gas, hold handle entire time and do not put pressure on filler neck.
The filler neck in my car was replaced in May, by the dealer. I had been experiencing problems with the gas pump shutting off during fill--I sometimes had to reset the pump 5-6 times to get a full tank of gas. I also thought I could smell a faint trace of gas in the trunk.
Since I had the filler neck replaced--about 4 full tanks ago--I haven't had any problems with the gas pump shutting off during fill.
The new (updated) filler neck was $121.11, labor $42.50. While there is a tech bulletin on the filler neck, I don't think Porsche has any plans to replace them free of charge.
Fuel smells in 964s seem to have multiple sources. The number one source, as the two previous posts have indicated is the filler pipe. On my car, the gas cap won't seat properly, so if I fill the car up with gas and then take it out on a twisty road, I can open up the filler flap and gasoline will be laying all over the area. This then leaks down into the trunk area.
I have developed a temporary fix for mine which was to kludge together a gas cap that would stop the leaking at the cap itself. This worked, no more leaking, and the smell of gasoline in the trunk is reduced by about 75%. Another owner stated that his y-pipe (the very filler pipe the others are talking about) also cracked. A kludge cap like mine is NOT a real solution, so I'm not even going to provide anyone with the details of it. My car clearly needs the new filler pipe, so I'll get one and install it.
Will it fix the problem? Hopefully, but I've heard of others having problems with other sources (rotting hoses, pinched gaskets on the underside feed to the fuel pump, etc). I need to trouble shoot this one step at a time.
Odds are it's the filler pipe. The propper procedure for checking this is to pressurize the the tank and then use an HC sniffer to try and find the actual source of the fumes.
Guys,
Here is the text from the relevant TSB from Porsche. It clearly identifies the fuel filler pipe as a source of fuel smells and what you need to do. I would check that you received the correct part number filler pipe if the problem persists. Take it back and make them carry out the Porsche Test as per the TSB.
Porsche does not provide warranty once the auto has passed its warranty period, normally!! (they have been persuaded in the past on some issues). These TSBs must be carried out whilst the auto or model range is still in production and or under its own warranty. If these TSBs had been carried out in 1994 they would have been under warranty. This was not the practice of the USA Porsche dealers as we have already learned. This is the practice here in Switzerland.
Ciao,
Adrian
911C4
Fuel Filler Pipe
Group2
Number
9401
Model
6 Cyl.
Part Identifier2007
March 10, 1994
Subject:
Fuel Filler Pipe
ATTENTION: Service Manager / Service Technician
Models Affected:
911 C2/C4 all
911 Turbo 1991-on
Concern:
If a customer complaint of fuel odor is reported, first check all connections on the fuel tank, filler pipe and cap for tightness and proper sealing.
Pressurizing the fuel tank with approximately 3 PSI and using an electronic hydrocarbon detector will find very small leaks which may be possible on the top of the filler neck or on the hose connections. If the fuel filler pipe shows signs of leakage in these areas, it must be replaced.
General Information:
If the fuel filler pipe is found to be leaking, only the fuel filler pipe with a metal band at the top should be used for repairs.
Parts Information:
Description Part Number
Fuel Filler Pipe 964 201 043 03
Not to argue with you, but not everyone with the fuel smell will be addressed by following the TSB. Most will, but not all. If I recall correctly the TSB says to pressurize the tank and use an HC tester to detect the actual source(s) of the odors.
Our cars are getting old. The pipe is clearly the source of the majority of odors being created in my car, and after having "kludged" a fix, I can safely tell you that although the odors are greatly reduced, they are not 100% solved. I doubt that replacing the y-pipe will do it all. Rubber likes to rot, and even though my car has low mileage, I seriously question the integrity of some of the hoses coming into and out of the system.
This is a problem that needs to be trouble-shot properly...by pressuring the system and tracing the source of the fumes, if possible.
Just my opinions.
Bill Wagner
'91 C4, now at 21K miles....I SAW it turn over on Saturday I've driven this car more in 6 months than the previous owner did in 5 years!
Dear Bill,
I agree with you. Not everyone has the same fault. However the TSB tells you to test first and seek the leak before changing parts.
I recommend this course of action where possible.
The TSB also identifies the main problem which should be fixed regardless.
My point of posting the whole TSB was to provide the required part numbers and to assist, not to solve everyones problems.
Many people in many areas end up with the wrong parts installed for a fix.
At least if people are armed withthe info they can attempt to get what they should have. I also addressed the question of warranty. Something I know from experience but I know that Porsche here are much more accomodating than they are in the USA,
Ciao,
Adrian
911C4
PS: Life would be so boring if everyone had the same problems solved with the same solutions. I would be out of a job for one.
After replacing a bunch of parts the smell is apparently gone....as tested in 90+ degree weather with the windows down and checking the trunk. Unfortunately I did everything in REVERSE order and may have spent more on this repair than necessary (ended up replacing all the parts shaded in yellow below). Per the technical service bulletin I replaced the fuel filler neck with the updated part with the metal collar ($550). I also replaced the gas cap seal with a new one and the two short hoses from the gas tank to the expansion tank (Porsche graciously only sells this hose by the meter). This did not fix the issue.
FINALLY I inspected the stop valve and found significant "rust and gunk" on the bottom outlet (see left pic below), which also spread to the hose going to the expansion tank.
I smoke tested the gas tank and the expansion tank and both were sound. I replaced the Stop valve on top of the expansion tank with the updated version (note the plastic top connecter that holds the hose better) along with the hose (again, Porsche sells only by the meter) from the valve to the underside of the expansion tank. I was concerned about "rust and gunk" having spread to the expansion tank and since it was inexpensive ($70) I went ahead and replaced that too. Lastly, I replaced the hose clamp on the hose going from the main tank to the stop valve, as the original appeared to be stripped.
Having completed that last batch of replacement part, the issue is resolved (fingers crossed). My best guess is the stop valve was the culprit, but who knows, maybe the stripped clamp (#5 in the diagram below) contributed. I highly recommend you inspect the stop valve FIRST when conducting your investigation.
I’ve chased that ghost for years. The gas smell first showed up in the late 90’’s. I replaced pretty much ALL the fuel tank parts including the tank. I had a new fuel tank on order from Germany and the Indy sold me a “used tank” instead. I should have proceeded with the new tank that cost at the time around $1,000 and was 4 part supersedes Just like the filler neck they kept updating the part. My last “replaced”part in the past 5 years was the charcoal canister. The small has mostly gone away but it’s still “there”. Maybe it’s baked into the interior or just part owning a 33 year old car. My 993 has never had a hint of fuel smell. Some people say it “smells like a Porsche”. Hope you caught the white whale…. It continues to allude me.
I had that faint fuel smell in the frunk for years........even after replacing the filler neck. When I 'refreshed' my AC (fuel tank removal required) I discovered the 'O' ring on the fuel sender unit was kinked. Replaced it and no more fuel smell!
See here: https://rennlist.com/forums/964-foru...-c-thread.html
Post #2.
I had that faint fuel smell in the frunk for years........even after replacing the filler neck. When I 'refreshed' my AC (fuel tank removal required) I discovered the 'O' ring on the fuel sender unit was kinked. Replaced it and no more fuel smell!
See here: https://rennlist.com/forums/964-foru...-c-thread.html
Post #2.
i had to replace my sender as well and was hoping I discovered the source. It seems to be an early 964 issue. (Mines a 1990). That’s why I’ve wondered if the fuel tank revisions made the difference. I’ll never know as they are now NLA and the 993 replacement part is over $2K. I’ve resigned to the realization “this is the way it is….”
Mines a ‘90 and I’m hoping that updated fuel filler neck and stop valve, both slightly redesigned. I was getting strong fuel smell that almost made my eyes water when driving, especially with the windows down, I hope the 964 fairies continue to now keep that smell at bay!
Mines a ‘90 and I’m hoping that updated fuel filler neck and stop valve, both slightly redesigned. I was getting strong fuel smell that almost made my eyes water when driving, especially with the windows down, I hope the 964 fairies continue to now keep that smell at bay!
FWIW it was the filler neck in my 1990 that solved it. But as mentioned above, it isn't the ONLY source of potential smells, it's just usually the most likely.
07-08-2001, 12:43 PM
Fuel filler neck leak
I've driven this car more in 6 months than the previous owner did in 5 years! 
