Gasoline vapor sniffer device

[chaseincats]

Hi all -

I can't seem to track down where my gasoline vapor smell is coming from.  Has anyone used one of those 'combustible gas sniffers' on amazon (like this) to track fuel vapor leaks down?

Edited February 9 by chaseincats

[siteunseen]

There's no fuel in the cabin so if that's where you smell it it's gotta be the weatherstripping. Easy way is to extend the tailpipe, maybe turn it down too. The rear hatch is usually the suspect.

If it's under the hood, most likely the cold start injector if everything else is right. You can make a new gasket out of a cereal box or gasket material. I used Fruity Pebbles or Coco Puffs, can't remember? Stay away from bran.

 

[chaseincats]

1 hour ago, siteunseen said:

There's no fuel in the cabin so if that's where you smell it it's gotta be the weatherstripping. Easy way is to extend the tailpipe, maybe turn it down too. The rear hatch is usually the suspect.

If it's under the hood, most likely the cold start injector if everything else is right. You can make a new gasket out of a cereal box or gasket material. I used Fruity Pebbles or Coco Puffs, can't remember? Stay away from bran.

 

I'm thinking theres a fuel vapor leak and its being pulled into the cabin in the same way as exhaust does with that vortex that forms in the back or via the firewall as my grommets are old.  Either way its definitely a gasoline smell and not exhaust which is why I was curious about the gasoline vapor smell.  My garage also smells like fuel when the car sits in there overnight.

That said, if we're talking about cereal box gaskets, I'm more of a frosted mini-wheat guy and heres why - stick with me here - it's the only cereal where you're not hungry after about 30 minutes.  That cereal has substance, I'm tellin ya, with sugar infused to make it palatable. 

[siteunseen]

#1 at my house way back when.

Now I'm a Frosted mini-wheats guy too, no milk, straight out of the box. No dairy...how bad that sucks, I miss cheese. 

[cgsheen1]

On 2/9/2025 at 3:17 PM, chaseincats said:

...  Either way its definitely a gasoline smell and not exhaust which is why I was curious about the gasoline vapor smell.  My garage also smells like fuel when the car sits in there overnight.

Evap tank? I was getting a slight raw fuel smell in the cabin when I left Goldie in the garage overnight with windows up. Took me awhile but finally discovered a crack in the plastic fitting (nipple, but we're not allowed to say that anymore...) that connected the evap tank hose to the fuel filler neck. Also wondered about the seal of the filler neck to the body under the gas cap fitting. There are a number of hoses and fittings associated with the fuel tank and the evap tank that could be suspect. (And many of them are in the cabin)

I've also seen the solder cracked on the tubing attached to the evap tank (as well as the fuel tank). The metal tubing that the hoses are attached to is all soldered to the body of tank(s) to mount and provide a seal.

[chaseincats]

1 hour ago, cgsheen1 said:

Evap tank? I was getting a slight raw fuel smell in the cabin when I left Goldie in the garage overnight with windows up. Took me awhile but finally discovered a crack in the plastic fitting (nipple, but we're not allowed to say that anymore...) that connected the evap tank hose to the fuel filler neck. Also wondered about the seal of the filler neck to the body under the gas cap fitting. There are a number of hoses and fittings associated with the fuel tank and the evap tank that could be suspect. (And many of them are in the cabin)

I've also seen the solder cracked on the tubing attached to the evap tank (as well as the fuel tank). The metal tubing that the hoses are attached to is all soldered to the body of tank(s) to mount and provide a seal.

I'd have thought so too but I pressure tested the vapor tank and all of the hoses by putting the palm of my hand over the outlets and blowing into them - it was a dreadful experience but it did give me the answer that there aren't any leaks there.

[cgsheen1]

To actually answer your original question: I've seen many technicians successfully use hydrocarbon sniffers to detect leaks on HVAC installs and on natural gas systems (even automotive A/C). (As a journeyman plumber, I just used "soap" type leak detector on pressurized piping)  Most don't use them for gasoline specifically but it should work just as well - a hydrocarbon is a hydrocarbon.

Let us know what you find - mine drove me crazy for months.

[chaseincats]

Just now, cgsheen1 said:

To actually answer your original question: I've seen many technicians successfully use hydrocarbon sniffers to detect leaks on HVAC installs and on natural gas systems (even automotive A/C). (As a journeyman plumber, I just used "soap" type leak detector on pressurized piping)  Most don't use them for gasoline specifically but it should work just as well - a hydrocarbon is a hydrocarbon.

Let us know what you find - mine drove me crazy for months.

Will do - the sniffer should be delivered today

[chaseincats]

Update: So that one I linked definitely worked (on the 'high' sensitivity setting) and taught me that my gas smell is actually coming from the engine bay, not the fuel pump area.

It seems that ALL of my clamps weren't keeping the fuel vapor in the rail when pressurized.  I cranked down all but injector #3's hose clamp almost to the max travel (because the injector #3's clamp screw sits right below the fuel pressure regulator so I'm going to have to think on how to get a screwdriver in there to tighten that one).  It seemed to help somewhat - I don't understand how these clamps aren't holding even this tight - the injectors and hoses are all maybe a year or two old and using the proper injector clamps (not gates belt clamps).  It also seems like all of the clamps slowly un-tightened themselves over the past few years because there's no way I had them this loose when I installed everything...

[Zed Head]

What type of hose are you using?  I had found that the Gates hose I got at O'Reilly's loosened up and need the clamps retightened.  Surprising since the hose is advertised for it's vapor control.  I think that the material "creeps" under pressure.  Probably needs a constant tension clamp to work best.

https://www.gates.com/us/en/fluid-power/engine-hose/fuel-line-hose.p.4219-000000-000003.html

[chaseincats]

1 hour ago, Zed Head said:

What type of hose are you using?  I had found that the Gates hose I got at O'Reilly's loosened up and need the clamps retightened.  Surprising since the hose is advertised for it's vapor control.  I think that the material "creeps" under pressure.  Probably needs a constant tension clamp to work best.

https://www.gates.com/us/en/fluid-power/engine-hose/fuel-line-hose.p.4219-000000-000003.html

The weird thing is this was the hose and clamps used on my remanufactured Bosch injectors:

 

It also applied to my other hoses using the same style of clamps, I don't get it

[chaseincats]

@Zed Head Where do you put your fuel injector's hose clamps on the fuel rail?  Do you keep them closer to the injector near the bump on the rail's piping or at the top?  I have my clamp on the top - since its further away from the bump, could it not be sealing vapors well enough?