2.8 twin plug gas smell
 

I have a 2.8 twin plug motor with MFI and RSR type cams. The car runs great, but runs a little rich. Every time I get out of the car I smell like gas. Is this normal and is there anything I can do to correct the problem. Can this smell be coming from the gas tank or is it a motor smell? The smell takes the pleasure out of driving the car.

Track it down...or carry a BIG fire extinguisher with you!
The fuel line runs through the tunnel....maybe it has a small hole in it....in any case...dangerous to leave it.
Bob

I don't see any leaks on the ground. I was thinking it was more of a venting issue or the smell of the motor coming inside the car. I stink after driving the car for a few minutes. My wife wont drive in the car with me.(maybe a good thing)

As Bob said, maybe a leak in the tunnel. A leak in the tunnel will not show drips on the ground. Gas vapors will end up in the cabin. You will have to remove your gear shift assembly and also the rear cover over the trans coupler, then you will be able to get a good look inside.

If the smell is from the exhaust pipe then your fuel system is likely out of tune and too rich.

Thanks for the input. I will check the tunnel out and have the pump adjusted. I am also looking into putting a check valve in for the gas vent. My gas tank gasket was saturated with gas. Do you think the smell could be coming from that as well. Are there any other areas around the motor that gas vapors could be escaping.

You haven't mentioned what chassis this engine is in or what air filtration system you're running. On most Porsches, there is a charcoal system to filter a lot of the fumes from the engines air filtration system as well as the fuel tank. In high performance cars it is not uncommon to see these systems removed or at least disconnected.

The chassis is a 72 911 converted to a 73. The emission equipment is removed from the motor and the gas tank is vented via 3/8 tube into the front fender well. I don't believe there is any other air filtration on the car. I smell like a gas station after driving the car. Your input is appreciated.

That doesn't sound right and could certainly make it's way into the cabin. You've got all kinds of wiring poking through down by your feet, some ventilation routed from there into the cabin, etc.

Todd

Yeah... the "gasket" around the gas tank is to keep weather from coming in around the tank into the bonnet area. Its not a fuel seal. If you have fuel saturation on that gasket then your tank is leaking.

I forgot to mention that I drove the car one time with the vent on top of the tank disconnected. The gas leaked out into the trunk and saturated the seal.

I would not worry about the lines in the tunnel. Just venting the tank to the atmosphere seems to be the problem. You need to install the evaporative emissions systems. In no way does it reduce performance. It can increase mileage by eliminating evaporation, vents the fuel tank to prevent vacuum of excess pressure, and will stop the dangerous fumes you are getting. If you search charcoal cannister and evaporative system you will find a lot of threads.

http://forums.pelicanparts.com/uploa...1373384819.jpg

Sully,
Do you think a check valve at the end of the gas tak vent will do the trick or do you think I need to get the whole set up. If so, do you have any recomendations where i can get the parts. Preferably used and cheap:)

The parts come up for sale. I've found parts I needed for mine. You could try an ad or do a search in the Used Parts Forum. If you're not looking for originality you can get parts from mid year cars.Porsche 911 Used Parts For Sale & Wanted - Pelican Parts Technical BBS
I don't think a check valve will be enough. It may let pressure build up at times, and I don't think the fuel system was designed for it and would still vent some fumes.

Thanks. I will look into it.

Doesn't take much of a leak to produce a gas smell (good thing you can smell as opposed to CO). Most are of the result of an occasional drip or vapor-leak type, more difficult to isolate.

Depending on your MY, the tunnel contains flex fuel lines. In the trunk, inspect item no. 1, the tank inlet hose. It's fabric and can/will eventually deteriorate and leak, more obvious when topping off. Liquid fuel observed at the tank-to-chassis gasket indicates a more serious leak. Try to follow any fuel leak path from above that location. Yes, there might be a pinhole or larger leak from the tank itself. There might be tell-tale signs of rust in your fuel filter that could indicate a self-destructing tank.

Sherwood

Thanks Sherwood,
I have all new gas lines running through the car. I am looking into a fuel vapor separator and charcoal canister. Hopefully this will solve my problem. I was thinking of putting in a check valve on the vent line, but someone thought I would run into fuel pressure issues.

Seams rust out. If the smell happens only some of the time... try running less than half a tank for a while. If the smell goes away doing this... could be the seam.

Here's a a rusting seam but not the one that was leaking.

http://forums.pelicanparts.com/uploa...1373543560.jpg

I am at a 1/4 full and it still smells. I am using a larger late model tank. I dont think that is an issue.
Thanks