Gas Smell in cabin

Recently have developed a strong gas smell in my 2002 Olds Bravada I have checked around getting no where fast I have been told the culprit maybe the fuel pressure regulator but with the engine running and I am under the hood there is no odor there is no odor outside the vehicle at all only inside any help is appreciated.

If the gas smell is inside, not outside, you may have a leak in one of the rubber hoses that carries fumes from the gas tank into the charcoal canister in the engine compartment. Mice sometimes nest above gas tanks and chew on those hoses, causing leaks. A leak like this will cause the cabin to smell strongly of gas.

Have a shop do a smoke test on the gas tank. They will blow smoke into it and the smoke will come out at the leak point.

A leaky o-ring on a injector could cause it too. I would start with the smoke test @jesmed said.

I don’t know the specifics of your car but, from my Porsche 944 experience, things to isolate, likely under the car in the rear :

gas tank location
tank filler location and connection to tank
fuel filter and flanking hoses

then inside the car, above the aforementioned items, sniff around the carpet/etc. looking for where hoses might be attached. is the level sender accessible from the interior?

things to look for: rusted fuel lines/fittings, rubber fuel hose with cracks - squeeze them… but if you are correct, the problem will be inside.

@jesmed 's suggestion is interesting too - the fuel recovery system… is it actual smoke they use?.. but whether the odor is inside or outside, isn’t it safer to assume it could be coming from anywhere? leaks in general - vapor, water leaks in a house - can travel to places you don’t expect. I also think when leaks in a car develop, the leak could very well be intermittent, depending on a number of factors - that is, not very reproducible.

I posted some things about the gas tank a while back if it helps…

+1 for @jesmed .

The regulator is mounted inside the intake manifold. If your regulator were leaking you would experience hard starts from the engine being flooded. I doubt that you would smell fuel from a leaking regulator as all the fuel would be inside the engine, not leaking externally. I would recommend smoke testing the evap system for leaks.

The odor source could still be a gas leak under the hood, even if the odor is only noticed in the cabin. Gasoline vapor in the engine compartment can get pulled into the cabin through the vents under the window, where it will accumulate. When you pop the hood and see if there is any odor there, you are outside and if the wind is blowing even slightly the gasoline vapor dissipates from the area quickly so you don’t smell anything. Gasoline has a strong odor so there may not be any sign of a liquid leak, or at most a little surface dampness somewhere in the engine compartment. A shop that has an emissions probe might can use that to isolate the area of the engine it is coming from.

RE: jesmed’s comments I once drive myself a little nuts looking for the source of fumes in my cabin. It was, indeed an evaporative emissions line - it had come off of its clip, fallen against the EGR feeder and melted in half. The fresh air intake had no trouble drawing in the fumes.

@JuniorMint, yes, they use actual smoke, though I haven’t seen the machine so don’t know how it’s generated. But it’s one of those tests that works well and gives immediate results. Smoke don’t lie when it’s pouring out of a leaking evaporative emissions hose.

Just for interest, I Googled and found this informative article about smoke testing:

Some people use a fancy smoke machine. Your casual weekenders are more likely to use a cigar:

It may be time to check the cabin area for rust through holes. Not that the smell should be disregarded, but if it does infiltrate, exhaust gases could be too.

I saw a new use for a smoke machine (new to me at least) on “Wheeler Dealers”. A car had a water leak into the interior, so the put a smoke machine inside, closed the doors, and looked for where the smoke came out - turned out to be a bad side window seal. Pretty neat.

Yeah, that’s very clever. Lots of people could use that trick.

I clearly remember guys at the Benz dealership lighting up and blowing smoke to find leaks in the central locking vacuum system . . .

You guys that worked for Saab, VW, Audi, etc. probably have similar memories

Ok, I see how they do it with the cigar, just take a big puff and blow the smoke into a tube of the system you are testing. Thanks for posting the vdo @cigroller; not having a smoke machine, that’s a trick I might could actually use some day.

I’m fixing to do it on our caravan. I’m thinking it has to have a tiny little vacuum leak someplace. Haven’t found it with stethoscope or butane yet though. If I get around to it, I’ll let you know how it worked out for me.

@jesmed I would think charcoal would absorb some percentage of genuine smoke that goes into it, and thus contribute to the wear of the absorbing material. just saying.