GeorgeCo

Continuing to learn about my new (to me) 996 C2. Latest issue involves fuel smell, stumble, and loud fuel pump. When I first start the car in the morning I notice that the fuel pump is quite loud. Not wake-the-neighbors loud and not ticking, but it's a noticeable whine that goes away after about 5 minutes. I was getting a slight fuel smell in the cabin so I checked the filler cap. The o-ring was cracked so I replaced the cap but I'm still getting a slight smell of fuel. Once the car is good and warmed up (like 45 minutes into my 60 minute commute), I start to lose power around 3500 RPMs. I'm wondering if all this could be related? Do these fuel pumps tend to die a slow, tortured death, or go suddenly with little warning? Anything else I should be checking for the source of the fuel smell like a breather off the tank some place?

Byprodriver

Don't know what year you have but may not matter there have been alot of fuel pumps dieing on the forums lately & they seem to go slowly making more noise & reducing fuel volume & pressure. The fuel cools the pump submerged in the tank so don't run the tank down low below 1/8th.

When I bought my 2000 in 2003 it had gas smell that seemed to come from passenger side HVAC vent. Under warranty dealer replaced evap valve with no change. Next time dealer replaced fuel level sending unit that mounts on top of tank to replace the o-ring. This eliminated the smell & it has not returned. So you should sniff around the fuel tank top (under battery tray) when you smell gas, if you think it's coming from there it is probably the upper o-ring & I would replace the fuelpump also (while you are in there) I think you can only buy the o-ring attached to a new fuel level sender & if replaced must be calibrated with PS2 to be accurate.

Ahsai

Is yours a '99? Have you replaced the fuel filter and spark plugs? Also, you didn't mean it takes 45 min to warm up the car completely, right? Usually a few miles of city speed (10-15 min0 will do unless your thermostat is stuck open.

5CHN3LL

Are you sure the whine you hear at startup is the fuel pump? That sounds a lot like the secondary air injection (smog) pump doing its thing.

The fuel smell could be a rotted vent line, a cracked evap canister, or a number of other things. If you expand your Googling to include Boxsters, you may get some additional traction.

Ultimately, smelling fuel/exhaust in the cabin might be hazardous... might be worth a diagnostic fee for your favorite grease monkey.

GeorgeCo

Thanks for all the replies. It's a 2000 C2. I recently did replace the spark plugs, coilpacks, and fuel filter. No it doesn't take 45 minutes to warm up, it just takes that long before I notice the fuel smell and start to loose power at 3500 RPM. That whine may very well be the SAI pump. If I open the hood when I hear that sound, where should that sound be coming from? I actually had to take the car to the dealer to get a new key programmed and they couldn't find the gas smell source. Never fails, the car knows when it's going to the doctor and they symptoms stop. I'll take a look under the battery tray. Does the 996 have any relevant hoses accessible from the right fender well that I should check?

GeorgeCo

Bad seal on the fuel sender unit (which had to be replaced with the seal) and a broken bracket holding the fuel pump. Ouch. This i$ going to hurt.... Get the car back tomorrow afternoon.

Hurdigurdiman

let us know how much it cost so us DIY guys can pat each others backs..

Hardback

Brutal... Finally starting to get you

Scoob, welcome to RL. Plenty of jokers and intensely accurate and experienced members here. I havnt experienced what your describing. keep in mind your car is over 10 yrs and will require some work. Heck, I've replaced many many many parts on my 02. This post reminds me of that.

We each do a lot of preventative maintenance. I don't have a solution but I can and will say that each of us should be willing and prepared to repair/replace/rebuild these 996s, cuz they are truly awesome machines and deserve to be driven and preserved.

GeorgeCo

arm+leg...

GeorgeCo

Actually wasn't as bad as I was expecting. I thought about doing it myself, but I don't like messing with anything related to the fuel tank or the instructions include "make sure you have good ventilation" and "make sure your fire extinguisher is charged and close by..." Good thing I didn't try to do it myself: I would have only ordered the sender and seal and had a big D'Oh moment when I got it out only to find the pump was bad too.

Hardback

Wise move. I replaced the fuel pump in one of our 996 race cars. This is a very tedious procedure in my opinion and not a task you want to perform without experience. the pump is very difficult to line up once inside the tank. Hardly enough room for your hand to fit through the tank opening. No matter how much light you have focused you have to install it blind and by feel. Then you must be careful that you don't damage the float or the gauge will not operate. Ask me how I know...