Gas Odour when AC is on????

[Hodgey]

Hello Brain Trust!!!

I wonder if anyone can help me understand why I get a strong smell of gas when I drive the car with the AC on? I just had the AC topped up, and had no issue with it until I started to drive it after being in the UK for 2 weeks.

Very strange indeed....any clues?



Thanks in advance

Neil

[Bob Kontak]

The AC air handling is a closed system. Cabin air is sucked into under the passenger wooden floor board and goes up thru the evaporator and is blown into the under dash center vent and side dash vents. It is goes in a circle It is like a newer car when using the recirculate function. No fresh air is mixed with chilled air.

You have a gas or gas vapor leak somewhere. First guess is the gas cap. Second is the white translucent expansion tank inside the front trunk. Third would be the connections between the two expansion tanks - the one mentioned and the bigger one in the driver's inner fender. The hoses are connected by metal piping that are welded into the inner fender under the fuse/relay panel. The small metal pipe is connected to the hose that then travels into the passenger compartment tunnel and eventually ends up in the charcoal canister in the passenger rear wheel well area.

The smugglers box is supposed to be sealed with a big o-ring of sorts so not sure how gas vapor is getting in the evap chamber.

Are you mixing any fresh air when the AC is on by using the dash levers? That would bring the vapor in from the trunk area.

Find the gas problem and it will go away.

[Hodgey]

Bob, thanks for the reply, I will have to examine all the points you identify.

I didn't think that the fresh air could interject with the AC air????

I think I will start in the trunk tomorrow and see if I can deduce anything...I will report on progress.

Thanks again Bob

Neil

[DRACO A5OG]

Check under the car at the fuel pump, the 4" X 3/8" may be cracked or weeping at the connection. If it leaks, the bottom of the smugglers box has a drain off for ice build up when it melts, unfortunately it also takes in outside air and it is about 12-14" away from the fuel pump.

+1 check in the trunk too.

Jim

[dshepp806]

Originally Posted by DRACO A5OG

Check under the car at the fuel pump, the 4" X 3/8" may be cracked or weeping at the connection. If it leaks, the bottom of the smugglers box has a drain off for ice build up when it melts, unfortunately it also takes in outside air and it is about 12-14" away from the fuel pump.

+1 check in the trunk too.

Jim

Bingo! Fuel pump area...4-sure!

Best,

Doyle

[Hodgey]

okay.....problem found.
I pulled off the stone guard and found nothing until I started the engine to pressurise the system and sure enough, the leak appeared from the pressure hose (the one with the banjo fitting on.

I had the suspension pan replaced about 16 months ago and it looks like when the suspension crossmember was refitted, the hose was between the body and the crossmember which is right at where the leak appears to be.

So, the solution is to replace the pressure hose.....any guidance on this one?

Neil

[Bob Kontak]

Originally Posted by DRACO A5OG

Check under the car at the fuel pump, the 4" X 3/8" may be cracked or weeping at the connection. If it leaks, the bottom of the smugglers box has a drain off for ice build up when it melts, unfortunately it also takes in outside air and it is about 12-14" away from the fuel pump.
Jim

Excellent!!! Of course it would suck outside air in since the evap motor sits on top of the evap and sucks air upwards. Every day I learn something here.

Here is the fuel line with the banjo fitting.

Pelican Parts - Product Information: 911-356-066-08-OEM

Rubber grommets:

Pelican Parts - Product Information: 911-356-202-03-OEM

Sealing rings at banjo fitting

Pelican Parts - Product Information: 900-123-005-20-M131

Here is a link to the catalog I used. See fuel section:

http://www.porsche.com/all/media/pdf/originalparts/usa/911_USA_87_89_KATALOG.pdf

[Hodgey]

Thanks to all for the assistance....now I know what I need to do and which pars to buy, I need to muster up the will to get this PIA job done......

Neil