Strong Fuel Smell Coming From Gas Tank...

[j.hardstyle]

I have a strong gas smell coming from my gas tank...not exactly sure where it is coming from.

The past few days, I have only been keeping about 1/4 tank or so...and at the beginning of the week, I had found one hard line that wasn't connected properly so I screwed the fitting on and thought that was the problem.

Fast forward to today, and once again I smell the strong gas smell inside the cabin. I fille my tank completely just an hour ago and that is when the smell started. Let me remind you, there was no smell when it was 1/4 tank but now with a FULL tank, it smells strong.

I did notice on the fuel pump cap, there are supposed to be 6 bolts, but there are only 4 holding it down. I was thinking maybe the gasket isn't sealing properly causing the smell....but wouldn't it do this at all times, even with 1/4 tank?

I can't see any visible leak anywhere, so I am kind of at a loss.....I do hear the fuel pump humming a bit, but then again my rear deck is removed and everything. I haven't had any drivability issues at all so I don't think the pump is bad. I just don't understand this strong smell when the tank is full.

Any ideas??

[Oatmealman]

sounds like you may have a flooded charcoal canister.

[j.hardstyle]

How would that make the smell come from the gas tank itself and into the cabin?

[Encryptshun]

Well, it's possible that with 1/4 tank, most of the vapor was kept inside the tank (if it's escaping into the cabin) and when you filled the tank completely, the vapors were pushed out through the path of least resistance (your cabin) instead of out the fuel tank vent.

Regardless, there is something wrong, and I advise you to have it towed to a certified mechanic. Don't screw around with gasoline vapors -- best case it makes you woozy -- worst case you turn into a roman candle. I'm overly-cautious that way (even if you do drive with the windows down).

[Q451990]

Typically we see this when the o-ring isn't replaced after removing the fuel pump sending unit - or the bolts are stripped out during reassembly.

Once you get the problem fixed, many members find that putting a bag of charcoal in the trunk absorbs the gas smell quickly.

Heath

[Bubba1]

Well, it's possible that with 1/4 tank, most of the vapor was kept inside the tank (if it's escaping into the cabin) and when you filled the tank completely, the vapors were pushed out through the path of least resistance (your cabin) instead of out the fuel tank vent.

Regardless, there is something wrong, and I advise you to have it towed to a certified mechanic. Don't screw around with gasoline vapors -- best case it makes you woozy -- worst case you turn into a roman candle. I'm overly-cautious that way (even if you do drive with the windows down).

Could be many things. For example, my wife's ' (new at the time) Mercury had developed a strong smell of gas after about 6 months. It turned out to be a small leak in the gas line located above the catalytic converter. It left no puddle as it burned as soon as it dripped. My mechanic said we were very lucky it didn't catch fire. It could be a crack in the filler pipe, if it's only bad when the tank is full.

I agree with Encryptshun about having it checked by a professional, and not to take chances when it comes to fumes. I also recommend towing it, but if you do drive it, drive it as if you just ate at Taco Bell. That is, window open, and no lit cigarettes. Both are potentially explosive gases.

[Rex]

Have you noticed no "pressure release" when opening the cap?

I'm guessing when pressure would normally build up in the tank it "escapes" around the loose fitting o-ring and more gas creates more pressure.

[300ZXttZMAN]

Fill out your location!

A problem on Z32's that happens everynow and then (especially with the old style injectors) Is that when the weather changes the clamps loosen up slightly and fuel leaks start..

I suggest you tighten all the clamps up and see if that changes anything. Even if you don't see it leaking still try and tighten it..

Hope that helps

[j.hardstyle]

Thanks for the replies....it is a 92 Q45...like I said there are two bolts missing from the top of the fuel tank where the fuel pump is. Instead of 6, there are 4. It could possibly be the gasket that sits around there....is there a part number?

Also, when I open the gas cap, there is pressure escaping, even when only 1/4 tank or even empty.

[Victor]

Many shops have something called a smoke machine that injects smoke into the fuel tank so they can find out where a fuel vapor leak is coming from. Its expensive to have it done but might be your only choice if you can't find the leak yourself.

[qship96]

2 bolts missing could cause the smell. Replace missing bolts and install new o ring.....or do the lazyman way by silicone caulking along the perimeter of top,but dont expect it to be a lifetime fix as the vapors could degrade the caulk,would last awhile though,maybe even outlast the remaining life in the ole Q.

[j.hardstyle]

I guess my only option for the moment is to try and get a new o-ring for the fuel pump and get the two bolts that are missing on mine....if that doesn't work then I guess it will have to be done at a shop.

[j.hardstyle]

2 bolts missing could cause the smell. Replace missing bolts and install new o ring.....or do the lazyman way by silicone caulking along the perimeter of top,but dont expect it to be a lifetime fix as the vapors could degrade the caulk,would last awhile though,maybe even outlast the remaining life in the ole Q.

Do you know if the o-ring can be found at auto parts stores or is it a dealer only part?

[qship96]

Amazon sells it,doubt the local autozone,etc carries it. Bosch #68203 $15 is the part to search for on amazon.

[j.hardstyle]

Thanks for the part number...O'Reilley's didn't have it so I went down and checked Napa. They had it for $15.69....going to change it out when my fuel level gets to about 1/4 tank, along with putting the 2 extra bolts in.

one thing though...when I took two of the bolts out, they were very very short. I'm not sure if they are just that way or if they had broken off when someone did the fuel pump before. The bolts have just a few threads on them, and I assumed since two were that way then they mustve all been that way...didn't take them out to check though.

[Infinitiguy19]

They are supposed to very short. DO NOT USE LONGER ONES!!!

[j.hardstyle]

I will probably have a hard time finnding that length bolt at the hardware store...any ideas on the part number? Actually, I may just pull them from the junk yard because there are two 90 Q's at the local pull a part.

[goody90q45]

Don't be surprised to find out that the two bolts are missing because the female threads in the gas tank top are stripped. Soft metal....overtightened bolts ....stripped threads.

You'll be able to find the metric bolts at an Ace hardware if you have one where you live.

[j.hardstyle]

Don't be surprised to find out that the two bolts are missing because the female threads in the gas tank top are stripped. Soft metal....overtightened bolts ....stripped threads.

You'll be able to find the metric bolts at an Ace hardware if you have one where you live.

Alright, I will check Ace Hardware...there are two close by. If the threads are stripped in the gas tank, what do I do from there?

[j.hardstyle]

Update....i just changed out the o-ring and got 6 new bolts/washers from Ace. There were no stripped threads in the tank...the bolts tightened up snug. The o-ring that was in there to begin with was really soft and flimsy, but the new o-ring was firmer, so that in combination with the missing bolts could have caused the smell.

I have charcoal in the back to help with the gas that leaked out of the fuel lines and will have to wait a couple days or whatever until i fill up again.

One thing though....when i was putting the pump back in, it seemed to have been stuck on something when it was almost all the way in. I moved the pump around and it finally sat down in there all the way....my concern is if the fuel pickup tube didnt sit at the bottom of the tank or what. If the pump sits like its supposed to, should i just assume the rubber pickup line and the float are sitting like they are supposed to?

[Q451990]

I'd be more concerned about the float binding on something... You'll know when you fill up and see where the fuel gauge level shows. I can't really imagine a way that the pickup tube could get misdirected...

Heath

[j.hardstyle]

I just filled up completely a few minutes ago and lo and behold, the strong odor is back. It was fine while I was filling up and it was fine for the first couple minutes of driving...then the smell became very strong. There are no visible leaks anywhere, all fuel lines are tightened properly, fuel pump sealed good....not sure where to go from here.

[j.hardstyle]

Just came out to the car after letting it sit a while...took a flashlight to the trunk to see if i could find anything and i did notice a wet spot at the grommet where the 3 fuel lines run at the bottom of the fuel tank. There was a bit of gas pooled right in one of the grooves on the grommet. But i didnt see any fuel leaking from the tank itself, which is odd.

This strong smell only happens when the tank is full, so im not sure whats going on here. Once the tank goes down to 3/4 or less then there is no smell.

[Q451990]

Just a thought...

Is it possible that your leak is coming in when you're filling the tank? Maybe the drain tube that sits at the bottom of the collar where the fuel nozzle goes that drains overfill spills to under the car is being fed to the trunk?

Heath

[j.hardstyle]

Well the thing is, if I put gas in and its only half tank or so, it never smells...so I dont think the fill tube leaks. Im not sure why the grommet has fuel...its where the 3 hard lines go into the floor, i see that grommet pooled with a bit of gas and it ran a bit on the floor. When i fill the gas, I stop when the gas pump clicks. I never overfill.

[j.hardstyle]

I took the car to a friends shop to get his opinion on the matter. He said he thinks it may be coming from the hard line to the right of the fuel pump. I think this is the gas tank vent tube....

At the fitting on the gas tank side, there is a bit of a "ring" around the bottom...kind of like a trench, for lack of a better word. It seems a bit "wet"...its not wet to the touch, but seems there is some moisture or something going on there. Its not leaking from the hard line, I dont believe because its tightened down good....but seems there may be something going on at the bottom of the fitting right at the gas tank.