Gasoline smell at times the smell of gasoline is very strong while driving.I don't see any gasoline under the car, i onder is it the fuel tank vapor relief valve.how does it get in the cab?

Strong smell of gasoline fumes means that there may be other issues involved than the O2 Sensor.
If it is enough of a smell that you believe gasoline is leaking in the engine compartment, I would not drive the car. The catalytic converter goes up to over a thousand degrees under the car after it is stopped. If vapors accumulate in that area. You could have a fire. NOT SAFE !!.
I would have the car towed to the nearest reliable service facility if you suspect a leak.
If you are working on the car yourself. Open the hood, pull the air cleaner and look for leaks in the fuel injection system. Along the fuel rails and where the injectors go into the manifold.
If it is just flooded then that could have something to do with the O2 Sensors. Please, use caution.
Hope this helps,
Mark

look under the back seat ,cover ,under the cover the sender unit ,one of the pipes has perished

If it is running fine, the busted bolt isn't the source of the gasoline smell. The intake manifold has vacuum, so the smell wouldn't be getting out, air would be going in, and a vacuum leak would give you poor idling. The exhaust manifold wouldn't have much raw gasoline smell. But it would have loud noise if the broken bolt were causing an exhaust leak.

Check that the vapor recovery line is not broken or disconnected. The hose connectors get cracked. If that were broken, it would cause a gasoline smell after the car has been sitting, especially if it has been sitting in the sun, heat driving gasoline vapor out of the tank. It is supposed to condense in the vapor canister, but some escapes if the line is broken. If it is broken, driving would **** out the gasoline from the line and the wind would dissipate the smell.

Or it could be a leaking injector. With the injector cover off, engine idling and cool, you can visually look for raw gas around the injectors and injector rail connections.

Hope this helps.

The problem is that your gas tank "pushes back" like it's full even when it isn't and makes the fuel valve click off. Tom and Ray on Car Talk covered this in a 2007 show and I pasted some of their response below:

"RAY: This condition is probably caused by either a blockage in your gasoline vapor recovery lines or a bad refueling control valve.

TOM: Gasoline vaporizes. How do we know that? Well, when gasoline is spilled, you can smell it, right? What you're smelling is vaporized gasoline.

RAY: And in the old days, when you filled up your tank, all the air inside the tank -- the air filled with gasoline vapors -- came whooshing out through the filler hole or through a vent at the top of the gas tank.

TOM: But then people in places like Los Angeles realized they couldn't see the person standing next to them due to smog. And since gasoline vapors contribute to smog, car makers were forced to install devices to capture those vapors.

RAY: So now each car has a vapor recovery unit that collects the gasoline vapors from the tank and then, the next time the car is started, sends them to the engine, where they're combusted. Your vapor recovery system isn't working, Lottie. One possibility is that one of the rubber hoses is blocked or collapsed."

The charcoal filter is used to filter fumes from the fuel tank. There is a vent line, that comes from your fuel tank to this filter. (Charcoal canister)

Now since the charcoal filter has been completely soaked with gasoline, it will no longer function as it should. Even with vapors from the fuel tank vent line, the canister only has a working 'life' of so far.
You will smell gasoline in strong amounts until it is replaced.

Can't comment whether it is safe or not. (In my thinking, you are driving around with a charcoal canister, that has a charcoal filter soaked with gasoline. I wouldn't use it this way, but that is just my thoughts)

Don't know this car but from the age, I'd start looking for damaged fuel or vapor recovery hoses

do u have a check engine light on? do u overfill the tank? which is to say when the filler nozzle clicks off do u still try to put more fuel in? in any event u most likely have a overloaded carbon canister, pull the canister out and check it for gasoline saturation, the carbon canister is located under the car in a tray near the fuel tank.

your brand new 1972 VW beetle may have as simple hole in the fuel line..when the car is not running you will not see any gas leaks becuase there is no call for gas to be fed to the motor.

have someone, or yourself crawl under the vehicle and look fort a small dripping or small stream of fuel.....REMEMBER!!!!!!!!!...gas is HIGHLY explosive and flammable...no smoking while checking/working on the rpoblem...and fuel's smell comes from Naptha, a chemical added to oil to make gasoline, it is a very strong ordor..a small amount can smell like a gallon.
hope this helps you

for sure there is fuel leafing but you have to locate from where, usualy this can happen from a leaking fuel pressure regulator and this can drip on the hot manifold and cause it to boil and smell the whole car secondly the vapor canister could be damaged and cause the same problem

Oh yes there is and there is a charcol canister up under the hood that captures the vapors if the canister is full you could smell fuel.
You will need a shop that has a SMOKE MACHINE to find the leak in the evaporative emissions plumbing from the tank to the engine compartment.

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