Sebastian

So I had bought a 2007 JKU earlier this year. When I test drove it, the tank was 50% full and everything seemed alright. However it became apparent pretty quickly that this JK had some kind of a gas leakage because after every fill up I could smell a strong fresh gas odor from between the rear doors and the rear wheels. This odor disappears every time the tank is less than 80% full.

I took it to the dealership and without further looking at it they replaced the filler neck under warranty because this is a common design flaw leading to spilled gas when you topped off the tank. But this was actually not the problem with my model. So lets call it a waste of time but it will be helpful to know that Chrysler has replaced a part for me under warranty on a six year old vehicle because this is going to be trial an error mission...

Two weeks later I was pretty sure that nothing had changed because the odor was still present with an 80% to 100% full tank. So I took it to the dealership again and this time they actually looked at it and told me the roll over valve of the tank was leaking and they would have to replace the tank for $540. Since they had taken their time to diagnose it, I thought that this must be money well spent. However even a new tank didn't help anything.

Since I don't have the time and money to have the dealership fix my problem on a trial and error basis, what else can cause a strong and constant odor of fresh gas while the tank is 80% to 100% full? The filler neck and gas tank are brand new and have been replaced by a Jeep dealership in the past few weeks. Would the EVAP canister be the next suspect?

jk.bushwacker

if you think there is a leak, fill it up and spend some quality time under the jeep checking all the lines etc. if you do not see any gas, find the leak or are unable to narrow it down by smell, then its time to test weather or not you are actually losing gas. if the gas leak is not noticeable at fill up time than the leak is small or nonexistent. make sure you do not overfill, top off or spill any fuel as this will add to the odor affect. also wear gloves while filling up and then store them outside the jeep. this will ensure the fuel smell is not coming from your hands after filling up. hope this helps and good luck!

Sebastian

I did that and my nose was unable to locate a single leak.

Also my eyes are not finding any apparent signs like dripping gas. I don't believe that I have a reduced gas mileage while the tank is between 100% and 80% but if so I am not able to tell the difference.

I agree that the leak must be small and maybe there are only fumes leaking which makes it even harder to find the leak.

Like I said, I think I didn't have an issue with overfilling and spilling gas before but especially after they had replaced the filler neck I can't imagine that the whole thing is just about some spilled gas. I have a 10 mile commute and if I don't go any place else, it takes days until the tank is below 80% and stops smelling. I can agree that not topping off would reduce the problem because the odor is not present once there is 80% of gas or less in the tank. However that would not fight the problem but just the symptom.

Living in New Jersey I am legally not even allowed to pump my own gas. So I am pretty sure that this odor comes from underneath the vehicle and is most noticeable between the rear doors and rear wheels on both driver and passenger side.

Sebastian

*bump*

Sebastian

I think I am gonna continue the trial and error mission myself and replace the EVAP canister next.

Any other ideas about what to look at will be appreciated!

Jeep1

Hi Sebastian, I have the exact same problem right now with my JK 08... I think It might be a vent on the top of the tank...
Have you ever found what th problem was?

CombatDiver

I'm familiar with states that prohibit you from filling your own gas tank, but it's ironic they will let you actually work on the gas tank considering such laws. There are a couple issues with the stock tank as indicated, you could get a larger after market gas tank that has resolved them or continue dealing with them as they come up. The gas smell sounds like the filler neck or valves on top of the tank. Having replaced both (a new tank should have come with the valves) I would imagine it's not. But there's always a chance they used the same valves on the new tank. Good luck!

Sebastian

In the meantime I have moved to Germany and I took my JK with me. A local shop here has successfully diagnosed and fixed the issue. It turned out that the New Jersey stealership, which had replaced my tank and the fillerneck, had reused the fuel pump. The cover of the fuel pump was cracked, and that's where the odor was coming from. I have a feeling that the New Jersey shop was planning to replace this only after everything else would have been done in order to take as much money from me as possible.

Anyway the German shop got me a refurbished fuel pump and this has completely stopped the fuel odor after fill up. However I still get CEL codes P0456 and P0457 which state loose fuel cap and small gas leak. After just ignoring these codes for some months now I have ordered a new gas cap recently which should be here within the next few days. I hope it is goning to be as simple as that.

Bottom line is, like CombatDriver said, even if the tank and filler neck get replaced, there can be still some old components in the system which get reused. In my case the service manager of the New Jersey shop had told me that the tank had to get replaced because the roll over valve in the tank was broken.

Yamaha90

I wish i had seen this thread months ago, i could have saved you all this time. The hairline fuel pump cracks were my problem as well. This also caused a lot of dirt ontop of the tank to become saturated with fuel, i was driving an explosion waiting to happen. I replaced the fuel pump with a new one and cleaned everything out and the issue was fixed.

Lynne Bridges

I have a 2008 Jeep Wrangler Unlimited and have gas fumes inside my Jeep. Took to dealership and they did a smoke test and also checked all lines and said no broken lines. Think they just assumed must be the fuel tank so after spending close to 2,000 was replaced. Well, problem still exist so have written down all the above suggestions and will be taking back to the dealership. I am a 68 year old female who loves her Jeep but am not knowledgeable about servicing it
myself. I am planning my yearly trip cross country in a few months so really want this issue resolved. Travel alone and the roads in Wyoming into Jackson hole can be pretty isolated. Really appreciate any suggestion you can give me when talking with the mechanic. Live in Columbia, SC