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Gas Smell

Cartrax

Well-known member
Joined
Sep 9, 2009
Messages
66
Location
Dundee, IL
Corvette
1984 Red Coupe
Trouble shooting gas odor - getting gas odor under heavy acceleration (more noticeable when tank above 1/2 full), will also get gas odor from rear as sun heats back of car area and slight odor noticed in garage as car sits overnight. Checked under hood, odor does not appear to be coming from engine compartment including canister area. Can't find any leaks under car. Pulled tank boot, inspected filler area, no evidence of leaks and cap is new feels like it's sealing properly. What else should I look for?

Also, how long should FP hold with only ignition on? Mine jumps up to about 29psi, needle shakes then immediately starts falling, within 10 seconds it's down around 3psi, sits there a while before it drops to 0. (1984 Corvette - High Output Fuel Pump - Vacuum Reference FP Regulator - FP gauge attached to VRFPR) That normal or an indication of a fuel line problem?

Thanks.
 

DonB

Well-known member
Joined
Mar 25, 2015
Messages
339
Location
Chicago
Corvette
2019 ZO6 in Elkhart Lake Blue
On my '90 C4 I had to replace the tank and the fuel lines due to rusting out. Fuel lines are along the inside of the right side frame rail. They make some wicked bends around the rear suspension. and the frame.
Also check the 1/4" vent line that goes from the top left of the tank and up along the inside of the left frame rail(bundled with the brake lines), up to the canister. That vent/vapor line can be porous from corrosion and be venting fumes.
In our climate, these cars trap moisture on top of the tank and the frame tank saddle area(not to mention road debris and SALT.) The outer sides of my old fuel tank were so bad I could practically push my finger through it. The lines almost crumble in your hand too. Should you need new lines, I bought new pre-bent lines from Classic Tube. They fit perfect.
Note that if the grommet around the gas filler is bad or it's drain is/was clogged, it will hold water on top of the tank. Check the sender assembly on the top of the tank. The fuel lines coming out of it are known to corrode too. Removing the rear license plate also gives you more visibility too.
All in all, you said it isn't holding fuel pressure. Even though you have an older/different fuel system than I; It's got to be going somewhere! Lotta variables here. Get her up in the air, check the tank and follow the lines.
Let me know what you find. Good Luck!
 

Cartrax

Well-known member
Joined
Sep 9, 2009
Messages
66
Location
Dundee, IL
Corvette
1984 Red Coupe
Thanks for the comprehensive reply. I found a leak in the rubber hose (evap line) near tank neck. Also found evap solenoid defective and decided to replace the canister just cause it looks original (=34 yrs old). Repaired lines they now hold a vacuum and waiting on parts. Hope that does it. Fingers crossed...
 

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