I have a 89 RS 305 TBI. When my car sits overnite or just for an hour or so, there is a pretty strong gas odor and I'm having a hard time finding it. Also when I remove the fuel cap there is a hiss from the vacuum pressure, My 88 V-6 does not do this. I changed the filter[or whatever it's called] on the fuel line under the side of the tank. Have no Idea what it could be.. Not leaking a drip of gas that I can see???

 

My gas tank hisses too when i open it. And I smell gas sometimes too but I think its *probably* just excess from inside the lines or the throttle body. Ever sniff that thing? I just put on an open element air filter and i think thats where its coming from.

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1992 Pontiac Firebird (stock)
- 305ci V8 TBI / Automatic Trans / Every option, excluding leather
- Killer car audio system:

• Aiwa CDC-MP3 head unit
• Rockford Fosgate 360a2 amp
• pair of 12" MTX Thunder 5000s in a custom box
• Pioneer 3-way 6x9s, soon to add more more more!

 

sounds like bad leaky injectors, check your tbi, a peice of wood under your injectors and let it sit over night, if in the morning you have wet peice of wood, you know whats leaking, there are other ways of doing that, but just dont use plastic cups, gas eats em.

 

sounds like bad leaky injectors, check your tbi, a peice of wood under your injectors and let it sit over night, if in the morning you have wet peice of wood, you know whats leaking, there are other ways of doing that, but just dont use plastic cups, gas eats em.

 

Checked the injectors and they're not leaking a drip neither is the throttle body. My original thought was the fuel tank top may have came loose and is letting fumes out but when the gas cap is removed it hisses so that means the tank is sealed. after it runs and sits for a while theres a gas odor anybody seen this??????????

 

Where do you smell gas? Did you check around your charcoal canister? Maybe a line came off of that or something...

Steve

 

Doesn't seem to be coming from the canister, All lines are in tact. It may be coming from the tank area. Does anybody know what the little filter on the 4th fuel line is for, it's mounted on dr. side just above rear axle???

 

EFI cars have pressurized gas tanks. Its not vaccume sucking air in the tank, its pressure blowing air out of the tank. The pressure sends the gas through the fuel lines with the help of the fuel pump.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

what pressurizes the tank, I thought they had a vacuum in them from the engine. Also what is the ventilator specifically for[it's the filter type unit above the rear axle on the end of fuel line 4?

 

think I found the problem. Somebody decided to mount an amp above the fuel tank and put holes right into it,being that it sits 1/8" below the rear dash....NICE!!!!!!!!!

 

lol good thing you don't smoke, ay?

 

Actually I do smoke in the car .And I'm thanking my lucky stars that I'm not cinged from a minor explosion that could of caused!!!