Fuel leak

Hi,

That could be many things. I attached a pic of the fuel tank below and highlighted areas that could be leaking. Note that the fuel filler tube, vent tube, steel fuel lines, fuel tank, and so on could be rusted and leaking.

I guess where we should start is by trying to identify where the smell is strongest. Is it in the front of the vehicle (engine compartment), does it seem to come from under the vehicle (center), or in the rear where the fuel tank is located?

Try to pinpoint a location so I can tell you what to look for. Also, take a look at the pic below. I highlighted several hoses, lines, and so on that can cause it. So, craw under the rear of the vehicle and inspect as much as you can. If fuel leaked, there should be a stain or something indicating where it came from.

One other thought. If it was related to the fuel supply line to the engine, it would be spraying out under pressure from the pump. Also, chances are you would notice a drivability issue. So, I'm suspecting it is the tank itself (likely on top), the filler tube, or the vent. Something that is preventing pressure to build naturally in the tank.

Let me know.

Take care,

Joe

See pic below.

Smells more toward center to rear on driver side. Plastic fuel tank. Also vehicle when stopped at light, idling, few times, it has almost shut off, like total loss of power. I just had battery and alternator checked 5 days ago.

Hi,

Based on that location, I suspect it is near or at the top of the fuel tank. If you safely lift and support the left rear wheel, it will help you gain access to see what is happening. What to do is this. With the engine off, have a helper turn the key to the run position while you check for anything near the tank or along the frame rail (where the line runs) that is leaking. When you turn the key from off to on (engine off), the pump will run a second or two to build pressure. At that point, you should be able to see if there is a leak.

If you are uncomfortable doing that, you can check fuel pressure and pressure drop off. With a fuel pressure gauge, simply connect it to the fuel system, start the engine, and then turn the engine off to see how quickly the fuel pressure drops. It should hold pressure for a good bit of time. If it drops off right away, we know there is an issue.

Here is a link that explains how to check fuel pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Most parts stores will lend you the pressure sensor.

Also, I circled a section of the tank where the fuel pump module is located. There are several points in that area that can leak. If you do remove the tire to gain access, make sure it is secured with safety jack stands.

Let me know what you find.

Joe

See pic below.

I removed the fuel tank today.
Its Arizona 107, hot, took lots of breaks.
Wasn't too bad.
So, the top of tank had lots of dirt on top.
I smelled the dirt and had fuel odor.
I removed the clamp and removed gasket.
Under the gasket, it was real dirty.
It's still off vehicle, just deciding if I should go ahead and replace fuel pump while I'm in this far.
We have lots of days over 110 here, and I'm sure that's hard on fuel pumps.
I'm just not surec100%"its gasket.
Could be other 2 top connections, but they were tight and looked okay.
My thought is; it leaked and the sand and dirt absorbed it before it ran down.
When I overfill it couple days ago, that's when I noticed more smell and used 6 gallons in 39 miles.
Almost twice as usual.
What are your thoughts?

Hi,

Wow, that is a lot of fuel you lost. Looking at the amount of dirt and considering you got about 6 mpg, does it appear that there is enough dirt to absorb about 4 gallons of fuel? That's a lot of gas. (basing it on getting approximately 20 MPG)

With the tank lowered and still hooked up, turn the key to the run position to see if there are any visible leaks.

Let me know.

Joe

20 might.
Obviously you never owned an Xterra. LOL
With oversized tires, if I get 12 to 13, i'm doing good.
So probably 2.5 gallons maybe.
Well, it's hot and very dry here, so possibly, some of it could have flew off while driving.
Its just weird.
But, that's super good idea, I will run it before I strap it in, check for leaks.
I mean the sand was damp and smelled like gas, so has to be leak up there from somewhere.
I checked under the entire vehicle and no leaks or smell.
More smell with full tank.
I'll see what happens tomorrow.
Thanks.

Make sure it isn't an EVAP component that you aren't getting a smell from. But that wouldn't explain the loss of fuel. Regardless, since the tank is out, make sure there are no disconnected hoses or damaged parts, specifically the charcoal canister.. See pic below.

Let me know how things turn out for you. I'm interested in knowing.

Take care,

Joe