Gasoline smell from a Chevy Express

[CaDreamin]

I have an odd problem with my 2004 Roadtrek Chevy 190P. If you have had a similar problem, please chime in.

When my gas tank is full I can smell gasoline when it sits in the driveway. It is not a strong smell, but it is distinct. It only happens when the tank is full or close to full. Otherwise I get no smell at all.

Weather doesn’t seem to matter. You would think it would only smell when it gets hot, but that’s not the case. It does seem to smell a little more on a hot day but I can get the smell on a cool morning as well.

There is no gasoline on the ground, no drips of any kind. A careful inspection underneath reveals no sign of drips.

I am aware of how dangerous fuel leaks are. I have had two different mechanics inspect the fuel system and assure me that there were no leaks. One mechanic actually removed the gas tank so the inspection was very thorough. I saw the gas tank outside the vehicle and saw no signs of leakage.

It seems that only vapors are escaping.

Have you had anything similar happen on your Chevy RV? Thanks for any insight you can provide.

[booster]

Originally Posted by CaDreamin

I have an odd problem with my 2004 Roadtrek Chevy 190P. If you have had a similar problem, please chime in.

When my gas tank is full I can smell gasoline when it sits in the driveway. It is not a strong smell, but it is distinct. It only happens when the tank is full or close to full. Otherwise I get no smell at all.

Weather doesn’t seem to matter. You would think it would only smell when it gets hot, but that’s not the case. It does seem to smell a little more on a hot day but I can get the smell on a cool morning as well.

There is no gasoline on the ground, no drips of any kind. A careful inspection underneath reveals no sign of drips.

I am aware of how dangerous fuel leaks are. I have had two different mechanics inspect the fuel system and assure me that there were no leaks. One mechanic actually removed the gas tank so the inspection was very thorough. I saw the gas tank outside the vehicle and saw no signs of leakage.

It seems that only vapors are escaping.

Have you had anything similar happen on your Chevy RV? Thanks for any insight you can provide.

There is probably an issue with the vapor canister or the controls around it. Overfilling, parking nose down with a full tank, etc, can also put fuel instead of vapor in the canister and it will smell for quite a while.


Do you have a tendency to overfill the tank, like many of us do?



I would start on a calm day and use your nose to try to find where the smell is coming from. There is probably and access cover in the driver side storage area that would let you get close to the gas tank connections to check there.

[CaDreamin]

Good candidates but I think I have already crossed them off. I had a situation where filling the tank went from merely difficult to almost impossible. I replaced the vapor canister and the solenoid valve. It did improve the fill situation, it got me back to merely difficult.

I use popsicle sticks under the pump handle to get a consistent flow rate that won’t click off the pump. Before I replaced the canister I had to use a flow rate that was so low that the pump wouldn’t click off. Spayed raw gasoline out from around the rubber pump boot. Smelly. Dangerous. So I started short-filling the tank and haven’t stopped.

I’ll try the idea about sniffing it out on a calm day.

[User1213]

Originally Posted by CaDreamin

Good candidates but I think I have already crossed them off. I had a situation where filling the tank went from merely difficult to almost impossible. I replaced the vapor canister and the solenoid valve. It did improve the fill situation, it got me back to merely difficult.

I use popsicle sticks under the pump handle to get a consistent flow rate that won’t click off the pump. Before I replaced the canister I had to use a flow rate that was so low that the pump wouldn’t click off. Spayed raw gasoline out from around the rubber pump boot. Smelly. Dangerous. So I started short-filling the tank and haven’t stopped.

I’ll try the idea about sniffing it out on a calm day.

On my Avalanche there are 2 valves in the EVAP system, one in the engine compartment and the big valve assy under the vehicle in the back. Recently I had a wiring arness that got rubbed through/shorted to the frame, cause all kinds of problems including filling issues.



It sounds like the canister might be full of fuel or blocked or possibly a bad EVAP valve.

[booster]

Originally Posted by CaDreamin

Good candidates but I think I have already crossed them off. I had a situation where filling the tank went from merely difficult to almost impossible. I replaced the vapor canister and the solenoid valve. It did improve the fill situation, it got me back to merely difficult.

I use popsicle sticks under the pump handle to get a consistent flow rate that won’t click off the pump. Before I replaced the canister I had to use a flow rate that was so low that the pump wouldn’t click off. Spayed raw gasoline out from around the rubber pump boot. Smelly. Dangerous. So I started short-filling the tank and haven’t stopped.

I’ll try the idea about sniffing it out on a calm day.

It might be a good time to try to address the filling issue, also. Getting the filling hose with a uniform slope and no low spots in the area of the driver side rear wheelwell has helped a lot of people, as it takes very little of a low spot to cause and issue. Most say the California vapor recovery pumps are the worst for slow filling, but I was pleasantly surprised when we were there this spring and didn't have any issue. I have our fill hose strapped as straight and uniform as I can get it. Being nose down and sloped away from the pump also help slow filling.

[CaDreamin]

Thanks for the tips guys.

I had no idea there could be a second evap valve. I’ll have look into that.

Access into the area above the gas tank would be very helpful, I’ll take a look.

I have considered taking a piece of aluminum angle and strapping the gas line into it with wire ties. I mean it looks pretty darn straight but I could strap it down straighter. I might be able to get the access I need by just removing the tire.

As far as the fill problem goes, if that doesn’t fix it one “crazy town” fix I’ve considered is adding a second evap canister. If the problem is indeed insufficient venting then putting a second canister in parallel with the first by teeing the lines and running them over to the second canister would give it twice as much venting.

If course the emission control computer might get all pissy on me if it saw something it didn’t like, and the state does frown on people who modify the emission control systems.

[booster]

I am not sure if a second evap system would do much good. I think that nearly all the venting when filling the tank comes out the fill tube as the vent hoses are very small. The evap system lets the tank breath with temp changes without putting the fumes in the air but is pretty low volume.


You will get pretty good access to the fuel line with the wheel off.

[User1213]

In order to troubleshoot the system you can disconnect the evap valve vent hose that connects to the fuel tank to see if it will fill.

If it does fill normally then one of the two parts is at fault.

[User1213]

and don’t forget to hook the hose back up after you troubleshoot...

[rhmcbride]

Hello

We have the same problem with the gas smell when our RoadTrek Chevrolet 2004 is full of fuel and parked on our slanted driveway nose uphill.
This makes the fuel filler cap about 12"-18" lower than the engine.

It goes away when we are parked level and the fuel level is lower.

No other evidence of fuel leaks or problems with the evaporative recovery systems.

[CaDreamin]

My driveway is dead level. Fuel has to be pretty close to full to get the smell issue. Temperature or time of day doesn’t seem to matter.

My evap canister and solenoid are recently replaced.

Originally Posted by rhmcbride

Hello

We have the same problem with the gas smell when our RoadTrek Chevrolet 2004 is full of fuel and parked on our slanted driveway nose uphill.
This makes the fuel filler cap about 12"-18" lower than the engine.

It goes away when we are parked level and the fuel level is lower.

No other evidence of fuel leaks or problems with the evaporative recovery systems.

[CaDreamin]

I might try disconnecting the evap hose. I’l be sure to hook it back up

[Sehc]

My Dodge has the strong gasoline smell. I tracked it to the vapor canister, the hose is off. If your cap was causing the problem, you could find that right away.