Strong fuel smell in cab while filling gas tank. 01 Silverado. Mystery.

[Gasbuggy]

Here's a strange one...my 01 Silverado, 8.1L 2500hd, I left it running while filling up at a gas station. It was late and I was the only one there. While the pump was running, gas fumes coming out of the dash vents was overwhelming. No gas smell under the hood, around the bed, no leaks underneath. But inside, very very strong.

Even on a short top off (7 gallons) you'll get strong fumes in the cab. Nothing when driving or running, you have to be filling up.

No CEL/codes.

 

[TCL]

Don't do that.

 

[Gasbuggy]

Do what? Leave it run? I've been doing that for years, especially if someone is in the car and it's hot or cold out.

 

[97prizm]

Here's a strange one...my 01 Silverado, 8.1L 2500hd, I left it running while filling up at a gas station. It was late and I was the only one there. While the pump was running, gas fumes coming out of the dash vents was overwhelming. No gas smell under the hood, around the bed, no leaks underneath. But inside, very very strong.

Even on a short top off (7 gallons) you'll get strong fumes in the cab. Nothing when driving or running, you have to be filling up.

No CEL/codes.

Sounds like a bad charcoal canister.

 

[Gasbuggy]

Sounds like a bad charcoal canister.

I think that's located under the bed

 

[JimPghPA]

Or bad purge valve. I know our 2001 impala had 2. One in the back, one under the hood.

 

[Glenda W.]

The evap vent valve is mounted on the drivers side between the bed and cab if I remember correctly.

 

[clinebarger]

No guarantee a 49-state '01 2500HD has the EVAP self diagnostic routine enabled.

Edit....I was curious & pulled a stock '01 2500HD 8.1L/Allison 1000 tune file & the only EVAP DTC enabled is the Purge Solenoid Circuit fault P0442 meaning the Purge Solenoid would have to fail electrically or have a wiring/connection issue.

All the highlighted DTC's would be active on a 1500 of the same year.

 

[clinebarger]

I would smoke/flow test the system at the Purge Solenoid vapor line (Purge Solenoid isolated) & the Vent Valve commanded closed via a scan tool.

If that checks out (Zero flow), Unplug the Purge Solenoid....A good/sealing solenoid will not allow vacuum to pass.

Pull the cannister & check for raw/liquid fuel and/or the presence of loose charcoal.

 

[Gasbuggy]

I would smoke/flow test the system at the Purge Solenoid vapor line (Purge Solenoid isolated) & the Vent Valve commanded closed via a scan tool.

If that checks out (Zero flow), Unplug the Purge Solenoid....A good/sealing solenoid will not allow vacuum to pass.

Pull the cannister & check for raw/liquid fuel and/or the presence of loose charcoal.

Cline, you tha man.

 

[Lubener]

Sounds like a bad charcoal canister.

That is a symptom of a problem. They don't just go bad by themselves. I would look for problems with the entire evap system, starting with the operation of the purge valve/system.

 

[Marcozi]

Scan the engine computer for codes.

 

[someonesomewhere]

That is a symptom of a problem. They don't just go bad by themselves. I would look for problems with the entire evap system, starting with the operation of the purge valve/system.

No, they definitely don't...but they sure will fail in a massive way of the vehicle is regularly 'topped off' after the pump kicks off. They don't like being filled with liquid fuel, but people get in the habit, whether to round their purchase up or an attempt to squeeze in every last drop of gas they can for reasons! Lol. Depends on the system design as to how sensitive the canister is to this issue.

I'm wondering though, if he just had the heat on and the vents set to fresh air instead of recirculate. That could be a difference maker going from AC season (usually on recirc) to the cooler months. Would surely suck in whatever gas fumes it could get it's maw on.

 

[Gasbuggy]

No, they definitely don't...but they sure will fail in a massive way of the vehicle is regularly 'topped off' after the pump kicks off. They don't like being filled with liquid fuel, but people get in the habit, whether to round their purchase up or an attempt to squeeze in every last drop of gas they can for reasons! Lol. Depends on the system design as to how sensitive the canister is to this issue.

I'm wondering though, if he just had the heat on and the vents set to fresh air instead of recirculate. That could be a difference maker going from AC season (usually on recirc) to the cooler months. Would surely suck in whatever gas fumes it could get it's maw on.

Yep, heat was on/fresh air. I rarely have it on recirculate. Stupid GM factory setting turns the AC compressor on whenever you set it to recirculate.

 

[someonesomewhere]

Yep, heat was on/fresh air. I rarely have it on recirculate. Stupid GM factory setting turns the AC compressor on whenever you set it to recirculate.

I'd investigate that path before I started throwing parts around willy-nilly. Next time you get gas, make sure that you obey the signs posted all over the pumps and shut your truck off. Make sure the windows are all up. Always start with the free stuff. Repeat 3-4 times and see if it stops doing it. Pretty much all of the EVAP stuff should throw codes, I'm pretty convinced you were just sucking in fumes. Cooler weather makes the fumes collect near the ground since they're heavier than air, and they won't dissipate if there's no significant breeze. Someone could have spilled gas near where your cab wound sitting, and fumes infiltrated via the climate control.

 

[350Rocket]

I have to use that mode

Yep, heat was on/fresh air. I rarely have it on recirculate. Stupid GM factory setting turns the AC compressor on whenever you set it to recirculate.

I have to use that mode whenever I leave the truck idling as the electric fans won't kick on until over 235F if the AC compressor is not on.....another stupid factory setting. Extra wear and tear on the compressor but I'd rather that then purposefully overheating the engine.

 

[Sedin26]

Gas smells really good. Just keep doing what you’re doing and enjoy

 

[Gasbuggy]

I'd investigate that path before I started throwing parts around willy-nilly. Next time you get gas, make sure that you obey the signs posted all over the pumps and shut your truck off. Make sure the windows are all up. Always start with the free stuff. Repeat 3-4 times and see if it stops doing it. Pretty much all of the EVAP stuff should throw codes, I'm pretty convinced you were just sucking in fumes. Cooler weather makes the fumes collect near the ground since they're heavier than air, and they won't dissipate if there's no significant breeze. Someone could have spilled gas near where your cab wound sitting, and fumes infiltrated via the climate control.

I've owned the truck for years, first time did it was this summer. It's something. I'm going to have to bring cardboard next time I fill at an empty station late at night. Poke around