2005 Impala 3.4 occasional gas smell.

[cousincletus]

My neighbor has an '05 Impala with the 3.4 engine and 95K miles on it. She is intermittently smelling a strong gas smell on startups, but no one can see any external leaks around the injectors. Does anyone know about this specific problem and where to start? Maybe there is a GM tech here that has experienced this specific issue before. Would taking an oil sample help to detect dilution from a bad injector. or would this be strictly an external leak?

 

[SAATR]

Sounds like he may have a leak in the vapor recirculation system causing the car to vent fuel fumes. Check the hoses and valves in the system for leaks.

 

[eljefino]

I figure a leak in the EVAP system or tank should light the CEL. An leak without a code would more likely be from the pressurized fuel system as there's no way for the computer to diagnose it.

My 97 silhouette with same motor leaked at a quick connect down by the subframe (to aid in assembly when they lift the powertrain in) due to rust but an 05 would have to be parked in a salt mine to have that issue already.

 

[cousincletus]

Corrosion shouldn't be the problem, as the car has lived its entire life in VA. No codes, either. I'm stumped, but will give a good look over before I suggest her to take it to the Chevy garage. It's probably a minor problem, but diagnostic time can be a killer.

 

[Bill in Utah]

Is the gas smell only when its in a garage or closed area?

Replace/swap out the gas cap. I had the same with my 2000 Silverado on start up. Did NOT throw any codes but replacing the cap did fix the smell...

Bill

 

[Schmoe]

Is GM having another intake gasket manifold problem?????

 

[cousincletus]

Schmoe, I was thinking about the manifold, but supposedly that problem was corrected sometime in 2003. It's weird, because it's intermittent. Bill, I'll tell her about the cap. That would be a cheap fix if that's the problem.

 

[Schmoe]

Maybe check where the vent pipes that run into the collection canister. Intake manifolds have been a problem for GM, especially the 3.X series engines.

 

[The_Eric]

An intake leak won't cause gas smell.

 

[SteveSRT8]

wow, some real bonehead diagnostics here.

Check the EVAP system as posted previously.

 

[The Critic]

This may sound a bit reckless, but as long as she doesn't see a large external leak, I wouldn't worry about it.

 

[mechanicx]

You might also want to check the fuel pressure regulator for leakage. It was still on the rail for that year.

 

[mechtech2]

All the "could be's" won't count if it is something else.
To check it yourself, open the hood in a closed area and have her turn the key to 'ON', but not start it. Look, listen, and SMELL.
Then try starting it and do the same.
Maybe after a try or two you will have this narrowed down.

 

[mechanicx]

And better yet hook a fuel pressure gauge up and check leak down rate and a scanner to check sensor values lol.

 

[MrCritical]

Be sure when fueling the car that you stop when the nozzle clicks off. Otherwise you will fill up the canister under the hood, and smell gasoline.

 

[sciphi]

The fuel rail quick-connects WILL leak given enough time and miles. It's possible one is intermittently leaking. One of the quick-connects on my car leaked a little when turned a certain way it would only see when servicing. Turning it back made the leak disappear.

And, it's not unheard of to have older GM's smell very faintly of gas for years with nothing the matter. Just unnerving is all.

Depending on the location of the charcoal canister, you can fill the whole filler neck without dumping gas into it. My Buick is set up like that, and an Impala may be similar.