Gas smell ONLY in cold weather.. 2002 Envoy 4.2

[leinhit]

Gas smell ONLY in cold weather.. ? very noticable
2002 Envoy. 4.2 6 cylinder 130,000 miles

This is my 3 rd winter w/ the vehicle. And when the weather turns cold (30 degrees or less I'm guessing), I constantly smell a heavy odor of gas .

Its driving me nuts ! I m not allowed to park in the heated garage at work anymore because of the smell.

No drips, no puddles, I've been under (not safe) while running with a flashlight looking for gas leaks / spray. Nothing .

The only time I found gas, was about a year ago I had trouble with a coil, I took the large black air intake baffle off to reach the coil. When I did, I found wet raw gas in there. Not a huge amount, but it was wet. I assumed it had something to do with the cylinder not firing due to the bad coil. Thinking it wasn't burning the gas, but doesn't really explain why it was in the intake baffle.

Again, this smell is ONLY in cold weather...

So, what are your thoughts Might explain the 17 mpg it goes down to in the winter months from 18-19 mpg.

I saw on another site something about top of fuel tank / pump leak? Is this a recall that won't cost me anything? I assume test by putting my hand up there (if fits, haven't tried yet).



Thanks all in advance..

 

[barron03]

Sounds like the fuel regulator.
View attachment 25556

 

[leinhit]

I think your right..

Just took the baffle off, and while running, the vacuum hose from the regulator to the baffle was dripping gas .. not at first, but after I put my thumb over it to feel for pressure/vacuum, then it started dripping, and dripping regular and large drops..

and in the baffle was wet gas, just enough to move around while tilting it.

** I assume it shouldn't be dripping that often? Whats the function of the vacuum line going to it.. for fumes or occasional over pressure relief? Why not just circulate it back to the tank?

Do I need any special tools.. like fuel line release tool?

$80 bucks for that little part ! At Napa.. $86 at auto zone

Or anyone have a better source?

Thanks for the reply.. appreciate it.

 

[The_Roadie]

Welcome! Saw your post over on the old site. That's a fuel pressure regulator with a leaky diaphragm. When the intake resonator vacuum drops after you stomp on the pedal, it controls the fuel pressure to the injectors to make sure more gas is available. It does use the quick-release fittings on the fuel return line.

 

[leinhit]

Cool.. came to the same conclusion..

I found the part at rock auto for $55, $30 less than auto zone.

and order the quick release tool kit.. 5 sizes for $5 bucks..


So looks like I have a project when they come in.. thanks for the confirmation..

 

[leinhit]

Looks like it was the pressure regulator ..

It starts much better and runs better.. always seem to run good, but the difference is now noticeable..

Still have some gas smell, I figure its still drying out or sucking out the oily gas residue from inside that baffle..

Oddly I was hoping my MPG would go up... down to 16.7 right now. but could be the winter blend fuel is bringing it down some.


BTW, you do NOT need a quick release fuel line tool as I purchased thinking I did... (auto zone repair diagram is wrong) the fuel lines come off very easily from the unit once you have the unit unbolted, / unsecured.. They just pulled off and the O ring makes the seal.

Thanks all for the input and the suggestions..

 

[Shdwdrgn]

Resurrecting a 3-year-old thread... I've been seeing a similar problem this weekend and wanted to follow up. Yesterday the temps were in the single digits (F) when we took a trip across town to my folks house (less then 3 miles). In that short trip we both smelled gas heavily in the cabin, and again when we got out. It also looked like my gas gauge went down a couple notches. When I got home I pulled into the garage and let it continue to run, but there was no dripping of fuel anywhere on the floor.

This morning the temps were below zero, but there was no smell of gas in the garage. I drove to work and the gas gauge only dropped the normal amount for my 25-mile trip, however I did faintly smell gas in the cab.

After finding this thread, I went out and looked under the hood. The pressure regulator mentioned was easy enough to find, although I don't see any gas pooled around it. Is there anything else I can check to see if this part is causing the problem?

Also Roadie, you mention that this controls the pressure when you stomp on the gas. This brings up another problem I've had since I bought the vehicle 6 years ago -- when I'm sitting at a stop, no matter how slowly I push the gas pedal there is always a short hesitation before taking off. Sometimes that hesitation causes me to practically rocket off the line when the engine does start revving. It has always been very annoying to me. I've even tried playing with the computer parameters in HPtuners and never been able to get rid of this problem. So could it be related?

[EDIT] Yeah no doubt about it, this is the part that is bad. I checked it when I got home last night and it was wet. Dried it off and checked it again this morning while starting the truck... Within about 20 seconds it started leaking fuel around the seams. Picking up a new one tonight, but prices haven't changed in the last few years. $86 from O'Reilly, I just can't wait for something cheaper to come in through the mail.

 

[Wooluf1952]

When I got home I pulled into the garage and let it continue to run, but there was no dripping of fuel anywhere on the floor.

When the FPR on my '03 Envoy went bad, I got a lot of gas smell. The FPRs usually don't leak outside the regulator. They leak thru the vacuum line into the intake resonator on the top of the engine. Pull the vacuum line off and check for gas in the line.