strong fuel smell

[WIFEYSQX4]

2002 qx4 3.5 noticed a strong fuel smell coming from outside of the vehicle on the drivers rear side(that's where it is most noticeable) but it only shows up after I've been driving around with the a/c on. Things recently replaced...fuel tank sending unit including lock ring and o-ring, vacuum bypass valve, and the fuel cap. Not sure where the smell is coming from exactly as I don't see any leaks under the vehicle.

ALSO...have not seen a drop in fuel mileage and no check engine light.

[atraudes]

Kinda strange you're not getting a CEL, but have a look at your fuel filler neck. There was a recall for them years ago but 2002 and up weren't covered. If that's not the problem, start poking around the EVAP hoses nearby and just start looking for moisture in the fuel tank area in general. There's an access hole under the rear seat under the carpeting that will give you access to the rubber fuel hoses and such on the top of the fuel tank. If you end up having to replace any fuel line, make sure you get hose that's meant specifically for EFI. Your fuel filter is also worth looking at and is located just above the rear axle (good time to replace it if it's due).

Good luck and let us know what you find!

[WIFEYSQX4]

ok its been some time and nothing has changed still have that fuel smell, but have narrowed it down to being most prevalent near the charcoal canister and noticed an increase in vapor residue coming out of the little block canister behind the fuel canister(the one for the fresh air flow) haven't changed anything else out yet as I was more focused on getting the car paid off before dropping more money into it, was told it could possibly be the idle air control valve or that I need to clean the maf sensor but there is definitely a noticeable drop in fuel mileage when a/c is running and not running like a 3-4 mpg difference. This is just baffling me and since I live in Las Vegas I wanna do as much as I can before taking it to one of these shady shops for evap diagnostics. Thank you in advance

[Mike W.]

All ears here as I have a pretty strong fuel odor in the same general location, but only when it's hot outside. It's not in the cap/filler area, nor have I had a chance to look for it yet.

[WIFEYSQX4]

yeah I climbed under there after driving it around for a bit and only found the smell in the area around the canister no where else, no wet spots no leaks any where its just in that area and only happens when the freaking ac is on which with the temps we have now is all the time. Even drove it 20 miles no ac in the 110 degree heat and no smell whatsoever. I'm about just ready to replace the entire canister and purge valve on the front of it just to see if that helps. But like I said before any info prior to forking out that money would be much appreciated.

[Mike W.]

yeah I climbed under there after driving it around for a bit and only found the smell in the area around the canister no where else, no wet spots no leaks any where its just in that area and only happens when the freaking ac is on which with the temps we have now is all the time. Even drove it 20 miles no ac in the 110 degree heat and no smell whatsoever. I'm about just ready to replace the entire canister and purge valve on the front of it just to see if that helps. But like I said before any info prior to forking out that money would be much appreciated.

Keep us posted as much for troubleshooting as not to replace unneeded parts. Looking into it a bit, damn, that thing isn't cheap, although Rockauto has them for half the dealer price. Dunno about quality, but...

[WIFEYSQX4]

drove to phoenix last weekend from las vegas and parked it, went to drive it the next day and the check engine light popped on finally with a P1456, small evap leak between manifold and canister, guess i'll be checking all lines and fittings around that thing before I take it to one of these expensive shops out here in vegas and have them throw a smoke machine on it.

[RR425]

I got the same thing on mine. Took it to a shop to check it out, they didnt see anything wrong so I kinda brushed it off. Thought maybe it is evap at cap.

[WIFEYSQX4]

I crawled under the other day after taking the QX to work and noticed no leakage but noticed excessive amounts of fuel vapor collecting at the fuel/water separator right behind the evap canister, I'm assuming the vent valve on the canister is sticking open and not closing when it needs to so I ordered one up(only $43) and will install and see how that goes.

[Kickinwing]

Before you decide to throw any more parts at your car, check your gas tank. These models are notorious for corroding around the fuel pump, allowing fumes to leak out. Nine times out of ten, it's accompanied by a CEL.

Open your driver's rear door and fold your seat bottom down exposing the fuel pump cut out in the carpet. Peel the carpet back and twist the three tabs holding the plate to the floor. They have a cutout for a phillips head screwdriver, but I prefer a nice, wide set of pliers. I always manage to damage the clips with my screw driver. Once you remove the plate from the floor, take a whiff. Also take note of any scab rust or corrosion around the fuel pump locking ring. Let me know what you find.

Keep in mind, the vent control valve is normally open at all times, unless commanded by the ECM. It is my understanding that the valve is commanded closed only during EONV testing (engine off natural vacuum) which occurs after the vehicle has been shut off. This usually happens over night, which is why most evap leak codes and related CEL's occur first thing in the morning.