2000 Silverado with the 5.3L
Smell of gas after driving. Throwing no codes, no fuel puddles after sitting for a bit, no wetness on the fuel lines or connections.
I am thinking the vapor canister is bad. What say you?

Check fuel tank and go forward from there. Checking the lines, etc. I once had a fuel injector that had a small enough leak that you could smell it but would not leave a puddle of fuel or any other visible sign it was leaking. If you’re in the rust belt it’s common for the fuel lines to rust through on those trucks, also.

I had a car like that. Found a very small line leak that was hitting the exhaust system. Gas evaporated without leaving a stain. I couldn't find the leak for the longest time. I assume that as soon as the mechanical fuel pump stopped the pressure in the fuel line dropped enough to stop leaking.
I could smell the gas every time I shut off the car and got out.
Sure was glad it never caught fire.

quote:

I am thinking the vapor canister is bad.

I have never seen one of these fail in such a manner that you can smell gas from the outside.
Given the rust issues this has had, I'd look at the steel fuel lines and the top of the fuel pump module.

Already been over all the lines and have located no visible leak.
A google search seems to show this as a common problem but no real fix is ever noted.

Does the vehicle run OK?

I have the same issue with a 2002 F250 Super Duty. Can’t find any leak.

Me three! (Xterra)

quote:

Originally posted by egregore:

quote:

I am thinking the vapor canister is bad.

I have never seen one of these fail in such a manner that you can smell gas from the outside.
Given the rust issues this has had, I'd look at the steel fuel lines and the top of the fuel pump module.

I have. I've had 2 different Toyota 4 Runners (1st Gen) in which the fuel charcoal filter emission canister allowed the smell of fuel. The first one is likely my fault as my typical practice was to fill the gas tank with as much as gas as I could pump into it, not knowing that this might lead to a problem with the canister. No codes.

The second 4 runner was a project vehicle with a completely different make engine and the original project builder either never fabricated a way or just got lazy and never connected the gas tank to the fuel canister and so fuel vapor was vented straight into the air.

I've also had a fuel injector with a tiny bit of gas smell around it, but I think it was still working, or at least partially working.

It could be a canister. But, in the good old days, there was a 'canister purge valve' on the canister. Not sure if yours would have this. The valve directs flow of vapor to the engine so it can be consumed there, when conditions warrant. I would check the lines from the canister to the engine. May be a simple fix.

^^^^^^^^^^^^^^^^
My 1990 C2500 shows the vapor canister with a thermostatic vacuum switch which allows the canister to be vented to the TBI. Maybe your switch is bad.

Did you check the lines on top of the tank, and the seal around the fuel pump opening? Pretty much impossible to inspect without dropping the tank or pulling the bed. Also, check the fill neck where it connects to the tank for dry rot.

My 2006 Trailblazer had the same issue, but I kept getting a check engine light that had a vacuum leak code. If your truck has a plastic gas tank like my Trailblazer, that may be the problem.

I replaced the gas tank and fuel pump and have had no problems since.

Do you round up at the pump after it stops?

quote:

Originally posted by cas:
Me three! (Xterra)

Me four (03 Camry).

look at fuel injectors too-small cracks or bad seals

I had 2 go bad in GMC trucks. Both at approximately 65,000 miles. Easy to replace. The only way I knew they were bad was they threw a code. One was a 2007, and the other a 2010.

There is a leak in your gas line somewhere. Not safe.

I have the same problem on my 1991 Nissan 300ZX, but only in the real hot weather when it has been outside for quite a while. No problems in cooler weather. No leaks, and new fuel injectors.

This gas that we purchase has a real high volatility index, and when it gets hot, the pressure in the FI loop increases. I wish I could find it as it stinks up my garage!!

quote:

Originally posted by jljones:
Do you round up at the pump after it stops?

Never

quote:

Originally posted by GT-40DOC:
I have the same problem on my 1991 Nissan 300ZX, but only in the real hot weather when it has been outside for quite a while. No problems in cooler weather. No leaks, and new fuel injectors.

This gas that we purchase has a real high volatility index, and when it gets hot, the pressure in the FI loop increases. I wish I could find it as it stinks up my garage!!

The problem did not develop until we were in the 90s for a long period straight and no rain.
We finally did not break 90 2 days ago.

Be interesting to see if the cooler weather remedies the issue.

All the lines have been checked and the bed was just off for the rocker repair and there were no signs of leaking but the smell was not there either.

Guess, I’ll pull the bed. Will help with rust mitigation as well.