SMELL OF GAS AFTER DRIVING 2005 4.2L 6

[Petnatcar]

Hi Guys,
After 7 years of ownership I recently noticed the smell of gas when I shut down the engine on my 2005 4.2 Trailblazer.

I don't see any leaks and the engine runs fine with good acceleration and excellent idle.
I have a new OEM Gas Cap and Filler Neck and Gas Tank and Fuel Pump assembly.

The Fuel Pump Regulator appears to be in the gas tank with the pump so I don't think the smell is coming from that.

Has anybody else experienced this unsettling phenomenon ?

Thanks,
Peter Carbone

 

[Mooseman]

Three times for me. Once it was the fuel rail that cracked at the test port, the other was the fuel pump was rusted on top of the tank, and then the fuel line was rusted.

Yours is a returnless system so no pressure regulator on the engine, it's in the tank. I wouldn't suspect the fuel pump since it is new.

 

[Petnatcar]

Thanks Moose,
Did you have a visible leak from the Fuel Rail ?
Pete

 

[Mooseman]

It was a very small leak that was evident only up close. Had to use my nose to find it.

 

[mrrsm]

For others in "The Rust Belt" Regions... Why Oh Why couldn't "The Feds" --require-- the Major Vehicle Manufacturers to use Stainless Steel in ALL Fuel Pump Assemblies...Since they are always so concerned with Conserving Every Last Drop Of Fuel that does NOT get BURNED???



Source:

trailblazer rusted fuel pump tubes at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

 

[Petnatcar]

For others in "The Rust Belt" Regions... Why Oh Why couldn't "The Feds" force the Major Vehicle Manufacturers to use Stainless Steel in ALL Fuel Pump Assemblies...Since they are always so concerned with Every Last Drop Of Fuel that does NOT get BURNED???

View attachment 114226

Source:

trailblazer rusted fuel pump tubes at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

I would bet the Almighty Dollar has something to do with that and it probably correlates to the Profit margin ???
Stainless is always more expensive but you have a valid point.
I had to get a new gas tank because the giant lock ring rusted /welded itself to the Fuel Pump and they couldn't separate them to install a new pump.
They could at least use Stainless on that friggin" lock ring...but we know that will never happen,
this is how they keep the parts supply line flowing, by using cheap crappy parts.

Remember when cars were actually made with steel ?

 

[Petnatcar]

It was a very small leak that was evident only up close. Had to use my nose to find it.

I can't see anything but the aroma is still there and there are no drips on the ground ?

Could the smell come back through my fancy K&N Filter and Intake Tube ???

 

[mrrsm]

This might sound crazy... and without the justification for using it in OTHER Automotive Diagnostic Applications... like identifying HOT Coil Over Plugs based on their Infra Red Signature on a Running Engine with a Suspected Lean Misfire Condition... Such a Tool might seem to be very frivolous. But in situations like this one, they are also useful for identifying COLD AIR LEAKS in HVAC Ducting, etc. In any case... I got mine last year and it has worked out great:

In THIS Particular situation... Due to the Danger caused by the release of Carbon Monoxide (CO) as Gasoline is Evaporating... the other phenomena is that Evaporation in and of itself is a COOLING Process... **** ... and so it might be easier to spot a small Gas Leak against the local warmer background --Safely-- and so by using this type of IR Camera... it could make it MUCH easier to find the Evaporating Cold Spots around the location(s) and hidden sources of Fuel Leaks.

THIS Handy Klein Unit was on sale back then and from the general search on the Quality IR Cameras, they all seem to run about *Three Benjamins* in Price and if you decide to use it and it finds your Mysterious (and very dangerous) Gas Fume Source... then it would be Worth Every Penny!:

Amazon.com

**** The Physics of WHY this Cooling Effect occurs are Simple:

In order for a Liquid to convert from that *State of Matter*... into a Gas...It requires ENERGY to excite the Molecules in the Liquid Fuel enough to separate and float away... and so it takes up the Energy of HEAT from its most immediate surroundings in order to Drive this Phenomena... by Scavenging that Energy and LOWERING THE SURROUNDING TEMPERATURE.

You can demonstrate this yourself by smearing a Drop of Water on your Forearm and while blowing air over that location, you will feel just how Cold it becomes as the Water enters a Phase Change and converts from a Liquid State into Water Vapor. Evaporating Liquids with such a High Volatility (VOC) Level like Gasoline should create quite a distinctive *COLD SPOT* Signature on a decent IR Camera Screen:

klein tools ti250 ir camera at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

 

[mrrsm]

THIS "Industrial Grade CO Specific Diagnostic Tool" IS Very Pricey... @ ($400.00) But again... If this CO developing via Gas Leak VOC Breakdown producing detection becomes intractable... the vehicle could become unsafe to occupy or drive.. .especially on long distance trips with the windows rolled up:

https://www.amazon.com/dp/B08B114PGK/?tag=gmtnation-20

It might also be possible to do the same Job with THIS ($13.00) "Basic CO Detector" ordinarily used inside the Home and Garage... and just walk it around until the alarm sounds around any particular engine spot or under the body and around the Fuel Tank:

https://www.amazon.com/dp/B08TRKL94H/?tag=gmtnation-20

 

[Mooseman]

I can't see anything but the aroma is still there and there are no drips on the ground ?

Could the smell come back through my fancy K&N Filter and Intake Tube ???

Sorry I didn't reply. Had a life event.

I doubt it came back out through the intake unless possibly you have a leaky injector. Best detector would be your nose and sniffing at the throttle body after shutdown. It shouldn't smell while running.

I'll bet it's a leaky rusted line. Might not be leaking enough yet to produce a heavy enough drip to be seen. I'd check the fuel pressure to see if it holds after it first primes without cranking the engine. It should hold between 50-60 PSI for a while without dropping. If it drops, I would jump the fuel pump relay and use the same olfactory (nose) and optic (eye) sensors under the truck along the fuel line. It might be a very slight crack in the line where it just sweats out.