Mechanics

FUEL VAPOR COMING FROM CANISTER AREA

2002 Ford Taurus • 162,000 miles

Whenever we get gas on the 2002 Taurus, and put the car in the garage, an unbelievable stench of gas fills the garage and the floors above. I did a pressure test and found no smells or leaks from the fuel rail on down to the tank. But there is an odor of gas coming from the canister mounted under the spare tire.

What could be causing fuel to get into the canister, or is it the canister itself or one of the purge valves? I really would hate to do the filler neck if it's something simple. I have no engine management issues, car runs fine, and no SES light comes on that I am aware of.
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Bravestar1
November 12, 2013.




Is it possible that you are overfilling the fuel tank? Also, have you checked tank vents to make sure they are clear?


Actually took this one to a garage today, and with a high powered light, they looked and determined the seal on the gas tank is corroded, and wet with gas. So every time you fill the tank and leaks a very little amount, over half a gallon. Garage wants $500 to replace the tank. I reckon I can do it for about $100-200. I did the one on the Mercury Sable, without blowing myself up, so just have to run the tank down so it's not so heavy, and get another one installed.


Tiny
Bravestar1
Nov 13, 2013.
Is it the tank that is bad or the rubber gasket that is leaking?


I'm not sure, I haven't crawled under there yet. I would assume though, there isn't a rubber gasket around where the seal is, as my mercury didn't have one either. Its just a welded/crimped edge that runs along the entire tank. I suppose I can slide under there and check.

On another note, while I've got you. I assumed incorrectly that the valve that controls the charcoal canister was bad (under the trunk), and wasn't closing when it was supposed to, to draw extra vapor into the engine. I get a strange gas problem, whenever I turn my car at a T either left or right, and it "pops" inside the engine. Also does it whenever I go up steep hills. I can jam the pedal and it takes a few seconds, but eventually I'll climb that hill at 4000 rpm and 55mph. I've replaced the gas pump, replaced the fuel pressure regulator, was going to replace the above mentioned item. Car drives for the most part fine (except at low speeds, where it tends to chug), but its hard to start when it warms up, takes 2-3 key turns to get it going again. Seems to be getting worse. Blew out the lines, replaced the lines, new spark plugs.I'm at a loss at this point. It's the 1998 Mercury Sable DOHC, but basically has the system as the forementioned Taurus.


Tiny
Bravestar1
Nov 15, 2013.
When you say it pops, do you mean backfire? Also, has the check engine light ever come on?


Yeah it backfires, a lot. It's not like my old Buick which made a backfire like fire coming out of the exhaust that sent the catylitic converter to hell, its more like popping in the engine. Once your not on a hill it settles down. And yes I have an SES light that mainly says, engine backfire and vacuum leak. But its insane how many gaskets I've tried to replace only to have the same codes and same problem over and over again.


Tiny
Bravestar1
Nov 15, 2013.
The odd thing about all of this is, if I take the battery off and clear the codes, the whole thing will run fine, especially in colder weather. Its not until that SES light comes back on after 40-50 miles of driving, that it will act up. I actually drove all the way up to NH on the highway and had no problems for 3 days. But the second I got out onto secondary roads and drove around from stop lights and stop signs it started to backfire and misfire like crazy. Its the craziest thing to fix.


Tiny
Bravestar1
Nov 15, 2013.
What gaskets have you replaced? Not to sound stupid, but is the throttle body tight? Have you checked for vacuum leaks using carb cleaner or something similar? If it keeps saying there is a vacuum leak, chances are there is. However, by disconnecting the battery shouldn't fix that kind of a problem. This is a tough one.

Let me know what you have done so far.
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I know, I've been dealing with it in various forms for 5 years now. It always lacked power backing up. My old car I could drive backwards at 40-50 mph, this one, can barely handle 5-10. Now you may ask yourself why some idiot wants to drive backwards at stupid speeds, but if you get stuck in the mud and try to hit reverse, the engine just ends up backfiring like crazy.

I've had the transmission replaced and that sorta helped it, but then the problem creeped back up. Replacing the fuel pressure regulator helped to decrease the intermittent RPM at idle problem. Replaced the fuel pump, notably because when I went to test it, caused it to run dry and then HAD to replace it. Along with the fuel lines which broke. There's no smell of gas, and I noted on the charcoal canister that there is NO gas smell, and wonder if a malfunctioning Canister Purge Valve. This would be that thing up front near the firewall that sends gas fumes to the engine. Course it wouldn't explain no gas smell, but then maybe Fords Run differently than every other car out there.

I was looking at the above technical bulletin, and after downloading all the codes I get, going to take the engine manifold off and check the plugs and see what looks bad.


Tiny
Bravestar1
Nov 16, 2013.
I went to Autozone and downloaded the following codes.

PO442 I've had this code since forever.

And PO420 also the usual code, even after replacing the O2 sensors in that bank (there's 2 of em)

But I also had a new code, for PO306, Cylinder misfire in #6. So we're gonna play with that today. And that could be anything I reckon, my guess is coil pack, since that's the most expensive, and that's usually what happens to me.


Tiny
Bravestar1
Nov 16, 2013.

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