possible fuel leak

68GTcarrie · 10-12-2009, 12:47 AM

Hey guys..

I've got some kind of fuel problem and not sure what the possibilities are, so heres whats goin on and maybe I can get suggestions:

Ive got a 302 4bbl carb, i used to get about 12 mpg but now its down to about 6. I dont see any obvious leaks, no puddles etc. but the smell of fuel is SO strong.

What are some things I can check so I dont sound dumb when I take it to a shop?

Thanks!

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tjsulli1 · 10-12-2009, 01:02 AM

Check your fuel sender unit on the gas tank. I just replaced mine last week..

Stepman · 10-12-2009, 01:08 AM

Sounds like you have a float issue....it in the carb. Does it keep stalling if you don't constantly clear it by hitting the gas pedal?

uibalnme · 10-12-2009, 01:15 AM

I don't see how a bad fuel sending unit could decrease MPGs. Maybe a bad fuel level reading, but nothing more than that. 1st, and easiest thing to do is to check your tire pressure. Alot of people forget about that. Also, your carb may have gone out of adjustment toward the rich side or a float problem as stated above. Readjust your carb if needed, check your plugs, air filter, ignition timing, PCV valve, all of the usual easy tune-up stuff.

68GTcarrie · 10-12-2009, 11:02 AM

Quote:

Originally Posted by Stepman

Sounds like you have a float issue....it in the carb. Does it keep stalling if you don't constantly clear it by hitting the gas pedal?

Yes it does stall! I'll check on that..

Thanks to all the replies!

kalli · 10-12-2009, 11:29 AM

things to check:
check the floats (what carb is it exactly? autolite 4100, holley, edelbrock ... )

remove the air cleaner:
- when the car is warm the choke butterfly must be fully open (the top flap in the primaries that you see without looking down the carb)
- when the car is warm and idling look down the carb, you shouldn't see any fuel being delivered. If it spills out your boosters then the butterflies are too far open, or the float level wrong. fuel pressure could be too high
- when you say it smells like fuel check around the carb for any leaks. it might drop on manifold where it evaporates, so it's not that obvious

Oxnard Montalvo · 10-12-2009, 12:17 PM

You have to determine if the gas is disappearing or being wasted. How does the car run? Black smoke? Stalling?
Does it smell while it's running, after it's shut off or all the time? Overnight?

As kalli and others have said check the float level and the carb/intake area for leaks. Do it while it's running and look for wetness. Scout around the fuel pump and gas lines all the way back to the tank. Check the tank itself and make sure the fill tube isn't split or loose.

Cutting your mileage in half indicates a significant problem so I wouldn't dick around.

68GTcarrie · 10-21-2009, 06:48 PM

Sorry for the late reply, just got back in town.

Its an edelbrock carb, I'll try what kalli suggested and see what that tells me about the floaters.

THanks

68GTcarrie · 10-23-2009, 06:49 PM

Ok I checked the floats and doesnt look like a problem there...

I did find that one of the gaskets under the carb was soaked with oil though, so I replaced that, adjusted my idle (needed it anyway), and will keep an eye on the fuel usage/smell.

Does anyone know why oil would even come close to the bottom gasket under the carb?

EDIT: Its not oil.. just really dirty fuel that looks n feels like oil. Hopefully the dry-rotted gasket replacement fixed the problem