Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?

[2001LC]

I had basically everything fuel-related replaced and still had issues...

Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?

I can not duplicate mine. Some hot days at sea level, some low elevation mountain driving, some regular driving on the highway on a 70° day. The worst was an 85° - 90° day on I-85 in north GA headed south. Could hear it at the gas station. Had an eighth of a tank or so left and it vented like an...

forum.ih8mud.com

Can you post up a list of parts?

 

[nikoli]

Heat shielding is helpful and can reduce or even prevent fuel boil. Installing heat shields and fuel line coolers, is not new. They treat the symptoms.

But it is not the same as solving the issue.

Agreed there is nuance between treating symptoms and curing the virus. I was responding to a poster's bold claim that the cause (ie the virus) is heat transferring from engine bay into fuel rails.

Earlier in the thread it seemed that ethanol was cited as the virus, but I didn't see much good evidence of that.

So far in this thread I've seen a poster cure his symptoms and form a pretty solid hypothesis that the symptoms are largely related to the proximity of the gas tank and heat sources. This is much more productive and scientific imo.

 

[nissanh]

I am going to go ahead with the fuel rail insulation. Just did 20 mile freeway and noticed the fuel rail reached 67 C

 

[nikoli]

Can you post up a list of parts?

Just reading down the shop invoice... this is in addition to the LRA 40 gallon fuel tank replacement kit...

Fuel Pump Tank Seal - LO218

Fuel Pump - E16127

OEM TOYOTA Fuel Shut-Off Solenoid - 7738026010

OEM TOYOTA Fuel Tank Vent Hose - 7701860110

OEM TOYOTA Canister Assembly - 7774060440

Quick Connect Hose Clamps

(As of this morning the LRA has been swapped into my "new" 2005 LX470... which I plan to mod as J1000 has recommended in this thread)

 

[J1000]

Heat shielding is helpful and can reduce or even prevent fuel boil. Installing heat shields and fuel line coolers, is not new. They treat the symptoms.

But it is not the same as solving the issue.

When is the last time you took your LX offroad up to 12,000ft?

 

[OEMGUY0720]

Is getting a new gas cap gonna help with this issue?

Theoretically no. The gas cap vents in atmospheric pressure for sub zero conditions to equalize pressure inside of the tank. Issue is more on effectively insulating the gas tank to mitigate high temperature and pressure inside and minimize the chances of the gas boiling. Fwiw, the gas cap vents out pressure from the tank when it’s hot but not as fast as it was designed when the OAT is cooler. Any gurus and experts please correct me if im wrong.

 

[DTC72]

No I didn't do anything to the fuel rails. Didn't seem worth it to me.

The #1 thing I did was to insulate the rear passenger corner of the gas tank itself. The factory heat shielding is missing from that location and it is also very close to the exhaust.

I followed @J1000 advice from this post several years ago starting with the corner of the gas tank and then wrapping all fuel lines from tank to engine bay. Haven’t had an issue since in Las Vegas heat or at high altitude in Silverton, CO. Wish I had done that before in the preceding years before replacing gas cap, fuel filter, evap canister, and a few other things that didn’t work. Someday when I meet @J1000 I am going to buy him dinner!!

 

[Reshala]

As an update:

1. Holy cow this is a quiet vehicle. I'm floored at how just how nice this is with an operational muffler. I had only heard it with the muffler holes and assumed that it's just a noisy old V8. It's quieter than even my current Gen Rav and Mustang. It's quieter than the 2003 Escalade that we loved. I'm in love.

2. With the new muffler I filled the tank and did 30 miles. Kentucky wasn't very hot today so it's not the torture test yet. There was no evidence of fuel boil or heat issues. The next few days will give better insight but I'm very hopeful that the groundbreaking idea of a functional exhaust system will have corrected the issue.

3. Did I mention that it's quiet?

 

[GVegasG]

I just experienced this with 04 going to Big Bear 100F.
What was used to wrap fuel lines ?

 

[J1000]

I like this heat shield tube: https://www.amazon.com/dp/B000CEO5T6?tag=ihco-20

I used this adhesive backed shielding for the gas tank itself: https://www.amazon.com/dp/B0844NGHS6?tag=ihco-20

 

[White Stripe]

Interestingly I found this chevy has a fuel line cooler.

 

[OEMGUY0720]

I like this heat shield tube: https://www.amazon.com/dp/B000CEO5T6?tag=ihco-20

I used this adhesive backed shielding for the gas tank itself: https://www.amazon.com/dp/B0844NGHS6?tag=ihco-20

From your previous post, this is what I got and about to put it on today:

 

[nikoli]

I like this heat shield tube: https://www.amazon.com/dp/B000CEO5T6?tag=ihco-20

I used this adhesive backed shielding for the gas tank itself: https://www.amazon.com/dp/B0844NGHS6?tag=ihco-20

I stuck the shielding onto my LRA tank yesterday. The LRA tank has a lot of odd contours that made it a little tricky, especially the rear corner. I decided not to cover the straps... which may or may not have been a bad choice lol, idk.

Haven't added any additional shielding for muffler or y-pipe yet, but will do so.

 

[OEMGUY0720]

Total of 6 pads used:

Complete side of the gas tank from the exhaust piping is now fully insulated as well as the fuel line between the tank and the evap.

Considered wrapping the Y pipe area and elbow pipe above the diff housing with thermal exhaust wrap, but I think that’s overkill and removing/installing 2 of the 3 the dissent skid panels is a major pita, it aint light at all.

 

[LARRYG36]

After last weekend's club meet and the tails we did, I'm thinking just shielding the fuel lines and cutting the Damn CATs off.

 

[Patron100LC]

I'm in FL so no altitude issues, but since replacing my cats with aftermarkets I saw a degradation in the rubber coating of the fuel lines that are really close to the exhaust system, the cats have a very little shield on top, so I fabricated a bigger shield, and wrapped the hoses. While there I did the gas tank and engine bay hoses. If my mileage improves, it's for @J1000

 

[DTC72]

@Patron100LC I did all that but didn’t think to wrap the fuel filter. Makes sense.

 

[Patron100LC]

I think it might help some.
I didn’t wrap the fuel line going to the passenger side rail, might use a different style shield since this one is a bit of a pain to use on hoses that bend in tight radiuses.

 

[OwnerCS]

I bought the insulation material to wrap the fuel lines and tank. Would it be possible to use an IR thermostat to locate hotspots in the fuel system compared to others to possibly isolate the problem areas? Also, maybe not optimal, I've driven all around the San Juan Mtns without the plastic engine cover. I wonder if the engine cover helps to hold heat around the fuel rails and engine. I wish I could test this before installation. Unfortunately, I have the fuel tank out as part of a larger fuel system reconditioning exercise.

 

[abuck99]

Craig

Engine cover doesn’t trap enough heat to make the problem worse.


Preface slow moving operation up-hill under load- The DS header and cat heat the fuel lines, the Y pipe heats the front side of the tank, and the muffler and exhaust heats the side of the tank. Those are the major contributors to heat sink and build up of vapor pressure.

The passenger side header and cat is right next to the Transmission lines- this heats the fluid- heats the radiator- engine runs hotter- and the cycle continues.

My 02- The evap can’t keep up with excessive vapor pressure with higher content of ethanol compared to original design- insulating fuel lines and tank skid (front and side) has shown to reduce the boil condition. I’d also consider wrapping the transmission hard lines by the header and cat.