Tracking the fuel smell

[deschodt]

Is there a smart way of tracking a fuel leak? For instance for oil you can spray foot powder on a clean motor and have fairly quick evidence of an oil leak...But I can't track the damn fuel smell...

I have a new fuel pump in the trunk, all new hoses there, it's all bone dry and smell free... The tank came out to do fender repairs, I can't recall such smells then, but since we went fuel injection with higher pressure, phew !!! The trunk smells strongly but there is zero trace of liquid gas anywhere. I've observed the gas being pumped and no leak from the rubber connector either. The vent goes to the gas filler...

I've had a mechanic look at it, he put a bigger charcoal canister, but nothing doing... Are there tricks I am not aware of (besides the flame of a lighter!!! it's a joke!!!) ? Thanks!

PS: the trunk seal is less than perfect... can it really suck in fuel smells from the exhaust ?

[jimk]

Of all the cases of fuel smell in the trunk, I haven't seen a positive solution on this board. You will get all the suggestions that you have already tried. I tried them too and I have the fuel odor. Done all the things you have. I even made sure the filler boot clamp is as close to the end of the fuel tank nozzle as possible to eliminate liquid fuel laying the space above the clamp.

I have come to suspect that the fuel today permeates thru the elastomer used in the boot material. If there is someone who accesses this board that is learned on that topic, how about a look at it. Gasket materials with the oxygenated fuels absorbed the fuel if the wrong stuff and the boot may do the same.

[BillWilliams]

I have tried all the solutions for a Euro vented car and still have trace smells in both cars. It kinda grows on you after a while and even expect it.

Getting the sending unit and the fuel pick-up unit sealed just right is also important, that helped some.

[esty]

another source of fuel vapor as i discovered is around the sending unit...a bad seal will allow vapor to escape but not liquid

just a suggestion that i discovered and repaired

[dubois]

that seal around the sending unit is really small, if it is not centered or installed correctly you get the smells.

I discovered the end of the return fuel hose to the tank being a little wet - it didn't even have a clamp! You may not see a wet spot, but just a bit of fuel vapor is enough to drive you crazy.

I think I have either solved my fume problem or became inmune to it!

Good luck

[akfjord]

This may be common knowledge many, but thought i'd share just in case... I recently conquered the strong fuel/exhaust smell in my car. Smell was most noticeable when the windows or sunroof were opened. I checked many of the recommended spots (rubber fuel neck, gas lines, pedal box foam cover, leaking tank, bad trunk gasket) and eventually just gave-in and got "used to" the slight buzz and minor headaches...

As it turns out, a brand new trunk gasket doesn't do squat if the rear sheet metal (where it glues down) is bent. On others recommendations I had tried sliding a business card along the seal from the outside to check for proper gasket/trunk alignment and it seemed to be sealing properly. However, after climbing into the trunk and having someone close it, light could be seen shining through 2 long gaps on either side of the trunk latch. So, when the windows or sunroof were opened, the cabin was pressurized, recirculating the stinky trunk air back into the cabin through the holes in the parcel shelf.

I guess the years of people leaning on that area, while getting things in and out of the trunk, had bent it. Very easily re-aligned with a few tugs on that panel.

So, get in your trunk peoples... just make sure you bring a screw driver, in case your helper decides not to let you back out.

[gracer]

When you had the tank out, did you look at the underside where it rests on the sheetmetal? When my TII was rearended I thought that the tank had ruptured at the seam. Turns out that there was a hidden rust spot between the support and the tank. I had been trying to find that smell source for the last 8 years. Not enough to show up as a leak untill the tank was hit. G

[vintage_car]

take few pics of the trunk area, around the pump, and the tank... I did this and within minutes someone gave me some advice on proper venting which helped out with my really bad fuel smell. Do you notice different potency of the fuel smell depending on the amoutn of fuel in the tank?

[02for2]

... Do you notice different potency of the fuel smell depending on the amoutn of fuel in the tank?

That's a really good point!

The fuller the tank, the less air there is to displace/occupy with vapors. Keeping the tank fuller will likely cutdown on the smell.

Cheers!

[Guest Anonymous]

Thanks for the replies !

No, the fuel level does not seem to make much difference (though I understand why it could). I will use some liquid gasket here and there to seal off sender and other places... I'll glue the trunk seal properly, too...

I'm leaning towards a slightly leaky tank just because I've almost ruled out everything else. Good news is no smells in the car itself, just the trunk (and my garage if the trunk stays open)

I did not realize it was a widespread 2002 mystery ;-) I feel better about it now... it's bad enough that food from the supermarket placed in the trunk for 5 minutes smells of fuel, not that I use this car for shopping much, but ugh, smelly...

[vintage_car]

Por-15 makes a tank sealant kit. It is a process, but anyone who can read instructions can do it. You might want to give that a whirl. You're lucky that the fuel smell is contained within the trunk...most have the vapors seep into the cabin. Open one window and it sucks it into the cabin and you begin to feel light headed quickly! It's fun!

[jimk]

So, just as I posted above, the suggestions were the things you already did. The worst one was the trunk gasket, like give up on the trunk full of vapors and seal the trunk lid (How about keeping the vapors in the tank). You will never talk your wife into setting bags of groceries in the trunk on that one.

Yes with the side windows open, the cockpit is under negative draft and draws vapors in from the trunk (talk to someone living on a dirt road, there you can see the dust creep in from the rear)

Being a bit sarcastic here, but I never heard a solution to the problem. However, I have another suggestion (that also didn't work) and that is to pull the tank and do a POR tank cleaning and sealing. I did it twice thinking the seam didn't get sealed the first time.

Also in all cases of factory build, the fuel line to the engine is under negative pressure in the trunk (Tii or carb). I have a 325 pump in the tank for the EFI and that also can have traces of leakage. I have installed double hose clamps there also. I am thinking of going back to the uder the car, in-line pump for a while like the Tii pumping system is which pulls fuel from the tank.

[im3crazy]

There is a gas smell FAQ going I think Bill Williams started it some time ago that's helpful. Also, here are two other:

(1) I had a seam leak (hardly noticeable) at gas tank where well documented gasket had failed, and

(2) I noticed that with a FULL tank gas sloshes up into the filler neck and runs down into the space between rubber boot and metal filler neck. It's not much, but it is more than enough to cause an odor. I now plug the top of the filler pipe with a rubber bulb from a gas siphon hose. It prevents this splash from leaking down and has totally eliminated my last remaining odor.

Other option: my sense of smell for gas has been destroyed over the last year!!

[TJF]

If you put the rubber bulb in hte filler neck, where is your tank vent? If it is in the rubber filler neck piece then you've essentially blocked the vent from the tank - it seems like you would end up drawing a vacuum in the tankl and eventually have fuel starvation problems.

Do you have another way to vent the tank?

[im3crazy]

Good observation. I was initially going to use a rubber ball. The vent tube is connected in the upper rubber boot area and the tank vent path is provided straight thru the siphon bulb. The vent goes out the floor of the car (euro venting).