hi, i have an imported FD3S, just got it not so long ago, the gas mileage is TERRIBLE, i only get bout 180km on a full tank of gas, the car is stock cept for the hks piping. anyways i just noticed in my garage where i park my fd theres some black stuff on the floor where my exhaust it, what it is? running rich maybe? could it be why the car is so bad on gas? i know i shouldnt complain bout gas mileage since its a sports car, just puttin it out there to let u guys know. thanks for the help!

 

here are some pictures
http://www.flickr.com/photos/35405397@N04/

 

I have seen that with my FC. I believe it's related to a pig rich fuel/air mixture. My speculation is that the rich mixture causes a buildup of unburned carbon (fuel/oil) deposits in the exhaust system over time and when you start the engine cold, the moisture in the exhaust system condenses, picks up some of the "soot" and spits it out the tail pipe. So, if the black stuff is kind of sooty and not very oily, I wouldn't worry about it.

 

It looks like water and soot.

Better tuning will help with the soot and smoke, but there isn't much stopping the water. The water forms when the exhaust system cools and it will spatter out when it warms up again.

 

so this is completely normal for an FD? also the strong smell of gas is always there when im driving, is that normal as well?

 

No. You should not smell gas when driving.

I recommend you do not start the car until you get it absolutely checked out for fuel leaks. FPD and injector leaks will lead to a very fast and intense fire.

Dave

 

I had a similiar thing with my saab. I had just run some injector cleaner through with the gas and the black stuff coming out the back was carbon buildup i had inside. Have you ever considered seafoaming your car?

 

ya looks like i have to get my car checked...
smell of gas when driving
very bad gas mileage, 180km to a tank wtf..?
loud back fire

what kinda problem am i lookin at?

 

i had the same probs with my 88vert. plus bad waterseals. cpet my fuel prob as FAR worse. i went 12 miles on a quarter tank. NOT good at all , my vert is in overhaul land or conversion land. tryin to locate an engien lol of some sort

 

If the car is stock, with a stock EMS and all stock fuel system, then running this rich is likely due to a failed injector. Have the injectors serviced by an injection shop and I bet you'll find one that was locking open.

By pulling the spark plugs, you can determine which rotor is running with the bad injector. The bad rotor will show horrid black and oily carbon deposits on the plug. The good rotor should be much cleaner.