Fuel odor

[gmcman]

I noticed this a couple days ago, this morning the odor was rather strong but no drips, nothing wet, FPR is dry, fuel filter is dry.

I filled it up tonight and nothing changed but the fact I can smell the fuel outside and inside has me concerned. I crawled under it tonight and the tank is dry, filler neck is dry, but the odor was noticeable towards the rear of the tank I couldn't smell anything when I was near the filter.

Could this be the seal where the pump/lines enter the tank?

 

[The_Roadie]

Or maybe a saturated charcoal canister?

 

[gmcman]

So that involves a fuel tank drop correct? Figures I just filled it up.

While I was under there the bottom of the TC case is weeping, and the LH side front diff seal is weeping.......

 

[The_Roadie]

The canister is back by the spare tire, not on top of the tank.

 

[gmcman]

The canister is back by the spare tire, not on top of the tank.

That was a welcomed sight this am........thanks.

 

[gmcman]

I will check it out tonight hopefully. Buddy of mine said it could also be a "vent valve" which apparently are a common item to fail over time.

 

[gmcman]

So what is the black box just in front of the fuel fiilter secured to the frame rail? Measures about 5x5?

 

[meerschm]

Hate to say this, but the fuel smell is just what I noticed just before my fuel pump corrosion resulted in failure and significant spill of fuel while operating. I too had just filled tank when it failed. I had a week or so between the smell and total failure.

http://gmtnation.com/f24/fuel-leak-top-tank-4063/

and asking the dealer for any relief did not do me much good in VA.

 

[meerschm]

So what is the black box just in front of the fuel fiilter secured to the frame rail? Measures about 5x5?

2002 GMC Envoy 4WD - TS0322701 Vapor Canister Lines, & Canister

Vapor canister, I think.

 

[gmcman]

Well i have my fingers crossed then for time being. Also the odor is continuous , doesnt matter how long it sits....if you are near it, then it stinks....even overnight.

 

[The_Roadie]

I see I misremembered that things moved between 2003 and my 2004. Sorry.

 

[Wooluf1952]

So what is the black box just in front of the fuel fiilter secured to the frame rail? Measures about 5x5?

I believe that is the Electronic Brake Control Module (EBCM), or ABS controller.

 

[gmcman]

I see I misremembered that things moved between 2003 and my 2004. Sorry.

No worries, haven't been under there but I should be able to run the tank out this weekend.

I believe that is the Electronic Brake Control Module (EBCM), or ABS controller.

I thought that at first except for the tubing entering the box, looks like it's definitely the vapor canister.

After reading about the recall it makes sense that the fuel could be puddling at the seal. Looks like a beast of a pump/sending unit, with a beast price tag.
Nice thing with having the fuel filter outside I can pull a line and pump the remaining into a can and the rest into the wifeys car.

 

[CaptainXL]

With the tank low you could pressurize it at the filler neck and see if it leaks air. The next step would be to block off the hose from the tank to the evap cansister and retest.

 

[meerschm]

the long duration of the smell does match having a liquid leak ( call it seepage)

really sucks that you have to drop the tank to see for sure. (if only they had included a service door over the pump!)

(non-GMT content below)
[video=youtube;ggcfn8MZhEo]http://www.youtube.com/watch?v=ggcfn8MZhEo[/video]


when I had the dealer change my fuel pump (happened just before heading to the outer banks for a week, did not have time for a DIY), they ordered a set of fuel lines with the new pump, might want to do that if you are ordering the part. you could always return the lines if you do not need them.

 

[CaptainXL]

Does it smell of fuel all the time? If it only happens when filling up the tank it could be a cracked filler neck.

 

[The_Roadie]

(if only they had included a service door over the pump!)

I'm just over 100K miles, and I swore long ago that if I ever needed a new pump, I'd slice in such a door to get at it. With my gas tank skid plate, it would triple the time to drop the tank.

 

[Wooluf1952]

Originally Posted by Wooluf1952
I believe that is the Electronic Brake Control Module (EBCM), or ABS controller.

I thought that at first except for the tubing entering the box, looks like it's definitely the vapor canister.


You're right. The EBCM is closer to the front.

 

[meerschm]

I'm just over 100K miles, and I swore long ago that if I ever needed a new pump, I'd slice in such a door to get at it. With my gas tank skid plate, it would triple the time to drop the tank.

don't suppose you have scoped out where such a door would go, and how to cut it out without damaging the tank, wiring or fuel lines?

Air Nibbler - Save on this 16 Gauge Air Nibbler

think this would work?

 

[The_Roadie]

Definitely a nibbler or air cutoff tool. Drill a 1/2" exploration hole first and use a Harbor freight borescope inspection camera gadget. If I do it I will post measurements up the wazoo.

 

[gmcman]

Does it smell of fuel all the time? If it only happens when filling up the tank it could be a cracked filler neck.

Actually wreaks of fuel most of the time, mainly during driving and if I walk near it after it has been sitting there is a faint fuel smell.


I went to the dealer today and picked up a seal and a vent valve in hopes one of them may be bad. Naturally I wont open them until I can confirm but since they are closed on Sunday I wanted to have them just in case.

What type of sealant could I use on the tank that's impervious to fuel if I need a small bead somewhere?

 

[meerschm]

does it smell under the hood?

 

[gmcman]

No odor under hood, centralized around rear axle.

 

[gmcman]

Sorry for the earlier post, I hit submit by accident.

So I dropped the tank which was actually relatively easy to do, just run as much fuel out as possible. Seems to some corporate folks, VA doesn't get much road salt....

Looks like meerschm was correct, about a week until it hits the fan. I can say for certain if you smell fuel don't wait it out, find the cause right now. I was lucky, that's a decent size hole in that elbow.

 

[gmcman]

Any opinions on pumps? I want to stick with OEM but not sure if Delphi, Denso, or even the AC is OE. I assume AC is but I only want to buy this once.

 

[djthumper]

Any opinions on pumps? I want to stick with OEM but not sure if Delphi, Denso, or even the AC is OE. I assume AC is but I only want to buy this once.

Here is slightly better price on the AC Delco ACDelco MU1837 Fuel Tank and Pump Module Kit : Amazon.com : Automotive

 

[meerschm]

Glad you found the leak before it really went.

 

[gmcman]

Here is slightly better price on the AC Delco ACDelco MU1837 Fuel Tank and Pump Module Kit : Amazon.com : Automotive

That's the one I'm going with, thanks.

Glad you found the leak before it really went.

No doubt, especially hauling the kids around. I'm ok with it for the most part, 11 years with a lot of fuel through it, having a fresh pump is good. I'm just glad it got me through the work week with no ill-effects.

 

[djthumper]

That's the one I'm going with, thanks.





No doubt, especially hauling the kids around. I'm ok with it for the most part, 11 years with a lot of fuel through it, having a fresh pump is good. I'm just glad it got me through the work week with no ill-effects.

There are times that I find parts cheaper on Amazon than anywhere else, most of their shipping I get in a couple of days.

 

[Real McCoy]

Just wanted to say thanks for the info posted in this thread. I started noticing a faint gas odor a week ago or so, at first I attributed it to the environment (gas station, fuel for lawn mower, etc) Then I checked around the engine and looked underneath and didn't see any evidence of a leak. Took my daughter back to school on Friday and over the 3 hr trip the smell got worse and stronger. Also noticed my fuel mileage was not up to normal. When I got home I did a search and found a couple threads about the fuel pump. Great knowing what to look for before I even get dirty. Pump was rusted like the pic GMCMAN posted. A long afternoon and this problem is behind me. Now just have to deal with the shift cable bushing and the liftgate module. Seems to be all falling apart at once here!!

Thanks again
Doug