fuel/gas leakage

[e30hereicome]

so I notice ive been getting terrible gas mileage, i calculated about 14 mpg. now I start to monitor it closely and realized that i started to smell gas. now first thing that came to my head was maybe the fuel injectors need to be tightened. previous owner had just changed the fuel tank and the injectors before he had sold me the car. now what else can it be?

[doucy2]

have you looked under it for obvious spots?

[Mike325]

Where does the smell come from? Front or back? Does it do it at full tank or at any other level in the tank? Have you seen wet spots on the ground?

[e30hereicome]

basically it smells like its coming from the front. po had replaced the fuel tank because the tank had a hole in it and was dripping a river of fuel, thats from the back of the car obviously. but when im inside the car i smelled it. now just after driving the car for a few times today i also realized that its only when the car is being pushed above 4k that i smell it. Ive also come to an idea that it might be the O-rings from the fuel injectors. PO said that wasnt replace when he replaced the fuel injectors. in reference to your questions, no there is no wet spots visible atm. and yes it smell whether the tank is full or not.

[Mike325]

After 4k huh? Did not replace the o-rings eaither huh? Sounds like the o-rings might be shot at the higher rpm. The injector is injecting more fuel so this might be why. Try driving the car, keeping it under 4k for a day. See if the smell stops.

[jlevie]

The odds are that one of the fuel hoses or the pressure regulator is leaking. I don't think that bad injector o-rings are going to cause a fuel smell, but leaks there would result in a rough idle (they are an intake leak). A loose clamp between the fuel rail and injector would be a problem.

[porsche gt1]

4000RPM = higher fuel pressure while driving. You could have a small hole that does not do anything under normal circumstances but when you push it up it leaks through the hole.

[ScottL]

4000RPM = higher fuel pressure while driving.

Sure about that? The speed of the main pump never changes nor does the setting of the pressure regulator at the far end of the rail, does it? To my knowledge, there is no regulator on the inlet side of the rail, so I thought fuel pressure would be more or less constant at the injectors.

The only thing that varies is the volume of fuel that bypasses the rail and gets dumped back to the tank - more at low revs, less at high revs. Am I missing something?

[Mike325]

I think that your right Scott.

[PeaveyBassist]

Scott is correct.

Will