Gas puked out of filler cap and major vapor pressure

[socalmtbiker]

Well I didn't get much action from Lexus headquarters as much of their attention is to customer service and not vehicle repair/issues.

And since the dealership could not replicate the issue nothing was done.

I can't accept this as Normal operation so I filled a safety issue to:

File a Vehicle Safety Complaint | Safercar.gov | NHTSA

I encourage anyone who has experienced this issue to file a complaint and make it more well known that it's more wide spread than just me. I truly think it's a design issue that needs to be addressed. For me to overland with my kids I need to know that I've address this.

 

[mp_cude]

98 LC, same issue at altitude...the tank vented high pressure for 15 minutes with the cap off. The paint on mine is also now pealing near the fuel filler door.

 

[TeacherMan]

I had a shocking problem with the 100 this Father's day weekend out in Colorado. When climbing Hayden Pass I started to smell terrible gas fumes at about 10,000' and assumed it was the side-by-side ahead of me. Then fuel puked out of the sealed gas cap, yes it was properly secured. You can see the route the gas took to escape here:

I stopped at the top of this pass, a mere 10,700', and could see fuel vapor roaring out of my fuel cap. I cracked open the cap and noticed an immense pressure release. After 15 minutes of pressure relief, I went ahead and pulled the cap and it continued vent for another 5 minutes or so. The charcoal canister under the hood was also making a popping or groaning noise. I had filled the tank to the first click then drove 35 miles to the trailhead, so it had to be down a couple of gallons.

It was hot this past weekend. 100 degrees. Yes, it was 100 degrees above 10,000'. I had the AC running full blast and the transmission was locked in 1st crawling up in Lo. The motor never heated up and there was not much stress on the drivetrain. I have no doubt heat and air pressure were contributors to the problem, but there must be an underlying problem that allowed the heat and altitude to have such an effect. The day before I drove up as far as I could on Mount Antero, about 12,500' before the snow stopped me. It was in the 80's and I had no issues.

I will disclose that during the drive to Colorado, my CEL illuminated between Goodland, KS and Limon, CO then turn itself off. The drive home was uneventful. No CEL and gas stayed in the tank. I pulled the codes when I returned home and had 4 active faults. To my surprise, nothing related to the Evap system was stored.
P0100: Mass or Volume Air Flow Circuit
P0101: Mass or Volume Air Flow Circuit Range/Performance Problem
P0110: Intake Air Temperature Circuit
P1121: [Toyota] Accelerator Pedal Position Sensor Range/Performance Problem.

The codes are pretty straightforward and should be easy to remedy with exception of the cost for the APPS

I've searched for help but have come up mostly empty handed in regards to the fuel puking out the filler. I haven't found any report of someone actually losing fuel out of a closed cap or having the amount of vapor build up that I had. I did see a few people have had excessive vapor build up and said it could be the charcoal canister but dismissed the problem as rare and not a concern. The charcoal canister was also mentioned as the cause for the slight pressure released when removing the fuel cap most 100's experience. I'd like to do some more research on this as the charcoal canister is $$$.

What could be wrong? This is a stock 100 series. I've never has this happen with any vehicle before, so I don't even know where to start. Am I on the right track looking towards the Charcoal Canister?

The EXACT same thing happened to me last week on Engineer. It really freaked me out. Some guys at the top said it was probably fine and should decrease as I descended, which it did. However, I'm with some others on this thread: that is not cool at all! I'll also be emailing Lexus today. Thanks for bringing this up!

 

[gatormark91]

The EXACT same thing happened to me last week on Engineer. It really freaked me out. Some guys at the top said it was probably fine and should decrease as I descended, which it did. However, I'm with some others on this thread: that is not cool at all! I'll also be emailing Lexus today. Thanks for bringing this up!

Don't bother emailing Lexus, you will get zero attention from it. The problem is almost certainly that your charcoal canister is worn out. Lots of threads here, easy to search for. You can test the purge valves through Techstream, even do a smoke test on the evap system. But at the end of that, it's still most likely the canister. It needs to be replaced, they don't last forever.

 

[socalmtbiker]

The EXACT same thing happened to me last week on Engineer. It really freaked me out. Some guys at the top said it was probably fine and should decrease as I descended, which it did. However, I'm with some others on this thread: that is not cool at all! I'll also be emailing Lexus today. Thanks for bringing this up!

https://www-odi.nhtsa.dot.gov/VehicleComplaint/

 

[gatormark91]

New vehicle emissions warranty is 50K miles. Not even sure what it was 20 years ago. This is not a design defect, it's what happens when a charcoal canister wears out. These get replaced all the time on lots of cars... You are on your own.

 

[Kabanstva]

How sure are you that replacing the charcoal canister solves this problem? I remember reading a few threads where a bunch of guys changed their canisters but the problem remained.

 

[87warrior]

I have done nothing to fix my initial problem since I am not comfortable throwing a $300-600 charcoal canister at it and simply hoping for the best. Awhile back there was a post here on mud about using a cheap replacement charcoal canister in the 100. It seemed promising, but I never got around to trying it. What I have changed is that I always buy ethanol free gasoline, or at the very least, premium. With that said, I have not had the problem happen again and I still fill up until the filling station pump clicks off.

 

[Kabanstva]

I have done nothing to fix my initial problem since I am not comfortable throwing a $300-600 charcoal canister at it and simply hoping for the best. Awhile back there was a post here on mud about using a cheap replacement charcoal canister in the 100. It seemed promising, but I never got around to trying it. What I have changed is that I always buy ethanol free gasoline, or at the very least, premium. With that said, I have not had the problem happen again and I still fill up until the filling station pump clicks off.

How do you monitor the ethanol content? I know around here in IL it's somewhere around 10% (one of my brother's cars is setup with Flex Fuel and a ProEFI display that tells you exactly how much ethanol you're running), but I have heard in other states that content is higher. What do you do on road trips if you have to stop for gas and the only gas station in sight has high ethanol fuel?

 

[87warrior]

How do you monitor the ethanol content? I know around here in IL it's somewhere around 10% (one of my brother's cars is setup with Flex Fuel and a ProEFI display that tells you exactly how much ethanol you're running), but I have heard in other states that content is higher. What do you do on road trips if you have to stop for gas and the only gas station in sight has high ethanol fuel?

Ethanol-free gas stations in the U.S. and Canada

I just trust the pumps when they advertise alcohol/ethanol free fuel. If it is not available, I run premium in hopes the higher flashpoint in the higher octane fuel will reduce the chance of gasoline boiling. It's not science and I cannot provide a fact sheet, but it has worked for me the last 2 years.

 

[8lifgr8]

Resurrecting a dead thread. Happened to me today in San Rafael Swell, not exactly high 4300-6k feet. But I have Imogene on my radar in a few days. I'll probably cancel. The vapors make the passengers sick and if you don't vent it manually, you can literally watch the vapor cloud bleed off. Talk about a huge fire danger.

It sounds like the canister is easy access, so I guess I'll call Toyota in Grand junction or Montrose and hope they have one in stock.

 

[87warrior]

@8lifgr8 OP here...and I feel your frustration. My Jeeps (MJ, XJ, TJ, WK) have never had a problem like this. I haven't found a fix to the problem yet, but I have been able to reduce the amount of boiling gas pressure by running at least 91 octane fuel and/or ethanol free fuel.

Just a couple of weeks ago my brother-in-law and I did a week long trip in the mountains. He in his 04 LX and me in my 99 LC. After one particularly slow and rough section of trail at about 8,000', he reported gas fumes and passengers feeling sick. We stopped and shut the rig off in an open area so the fumes wouldn't collect around us. Some fuel escaped the gas cap and the vapor cloud was big. We could hear fuel boiling in the tank and let it cool for 1/2 a hour. He was running 87/85 octane fuel at this point, but started using 91 afterwards. We did not have a problem the rest of the trip which took us towards Silverton, CO and over almost 13,000'. Coincidence, dumb luck or a possible fix? I have no idea.

 

[saucebox]

Resurrecting a dead thread. Happened to me today in San Rafael Swell, not exactly high 4300-6k feet. But I have Imogene on my radar in a few days. I'll probably cancel. The vapors make the passengers sick and if you don't vent it manually, you can literally watch the vapor cloud bleed off. Talk about a huge fire danger.

It sounds like the canister is easy access, so I guess I'll call Toyota in Grand junction or Montrose and hope they have one in stock.

Replace the CC, replace the gas cap with OEM. And @87warrior has a good short-term fix—don't fill up the tank all the way at elevation. And try not to keep pumping gas after the pump clicks off.

A gas cap solved it for me last year about this time, and I was able to run Imogene with a full tank and no problems. I'd previously seen the boiling/venting just going up American Fork Canyon.

I'll have a CC on order shortly—I'm still venting some at elevation, noticed on a trip last week to Colorado Springs.

Lots more info here: 100 Caught fire & gas tank venting concerns.

 

[suprarx7nut]

FYI, I ran into this problem for the first time ever a couple weeks back. I was at the top of Chinn's Lake near Idaho Springs, CO.

Elevation: 11,000 feet.
Temp: ~70F
Gas: Premium (91) from Costco
Tank level: around 50-70% full.

Solution: Do nothing. We just let it vent as we drove ~5 mph at the top and it went away on it's own.

Naturally, this is right before HIH and I'm planning on running lots of high elevation trails. I'll probably buy a new OEM gas cap and just keep the tank low. I'll also pack my fire extinguisher.

 

[8lifgr8]

I never "top off" but I did do a test run up skyline. I did fill up full, but my symptoms did not show up until 3/4 tank. Then it vented while driving, the passing side by sides all gagged from the vapor plume as they passed me (10k feet). At lunch we dropped to 9500 ft and had the "boiling" sound, but there was no venting or smell. An hour into lunch it equalized and no pressure in the tank (I could open my cap).

I ordered a cannisters and cap for pickup at delta Colorado Toyota ($500). I hope it fixes it ..my symptoms aren't as bad as some on this thread, but it's crazy rediculous for 137k miles.

@suprarx7nut, it's getting progressively worse. Doing nothing is not an option, passing vehicles are literally driving through a cloud of gas, and there is enough that I'm probably wafting gallons into the atmosphere.

Attached is the photo of mine at 10k feet, the dust shows the path of the gas. I'd hate to imagine what it would look like at 13k..

 

[nnnnnate]

@8lifgr8 has your rig shut off yet while venting fuel out the cap? Thats the next feature to experience. For me its always come hand in hand. Last thursday I was ripping up i80 to Evanston WY from SLC and took the Coalville exit and my LX shut off while coasting down the ramp. I pulled into a gas station and sat for 20 minutes before it'd start back up. Time before that I was towing a car hauler to WVC from Erda with 1000 sqft of sod on it and it shut off on me on 201 at a light. Its always inconvenient but always "resolves" itself after sitting for a bit. I'm here now looking for the thread I saw last summer about adding a heat shield to the fuel line that runs up the frame close to the exhaust to followup and see if that helped that user. Still looking for that thread though.

 

[saucebox]

@8lifgr8 has your rig shut off yet while venting fuel out the cap? Thats the next feature to experience. For me its always come hand in hand. Last thursday I was ripping up i80 to Evanston WY from SLC and took the Coalville exit and my LX shut off while coasting down the ramp. I pulled into a gas station and sat for 20 minutes before it'd start back up. Time before that I was towing a car hauler to WVC from Erda with 1000 sqft of sod on it and it shut off on me on 201 at a light. Its always inconvenient but always "resolves" itself after sitting for a bit. I'm here now looking for the thread I saw last summer about adding a heat shield to the fuel line that runs up the frame close to the exhaust to followup and see if that helped that user. Still looking for that thread though.

Same thread, this should be the post: 100 Caught fire & gas tank venting concerns

 

[8lifgr8]

Wow, haven't had it shut off yet. Does swapping the cannister fix it??? Nobody seems to post what they did to resolve it?

Vehicle runs great, no CEL, not rough running, just a huge vapor plume of gas. I worried mainly of fire....and my paint!

 

[gatormark91]

Wow, haven't had it shut off yet. Does swapping the cannister fix it??? Nobody seems to post what they did to resolve it?

Vehicle runs great, no CEL, not rough running, just a huge vapor plume of gas. I worried mainly of fire....and my paint!

These things need to be in correct working condition:
1. VSV on the intake (the one thing most people don't check)
2. Evap pressure sensor (comes with a new canister if you buy one) - same for the evap VSV.
3. Evap canister
4. Gas cap
5. Check for exhaust leaks. If your muffler is the tiniest bit noisy, you could have exhaust heating up the gas tank. This was the eventual cause of my fuel boiling. New muffler, no more boiling. Heat is the enemy in a recirculating fuel setup - if the heat won't get dissipated, you'll never get the fuel boiling to stop. Since increased pressure causes heat, evap issues will cause the fuel to heat up, too, adding heat to the loop.
6. Check for a rich condition in your O2 sensor readings in Techstream. If your O2 sensors are working but not giving good readings (ie - no CEL), the extra fuel the ECU will dump in to correct will seriously heat up your catalytic converters, which will boil the fuel in the lines that run next to the driver's side cat. Same goes for vacuum leaks, they can cause a rich-running condition.
7. Stop using gas containing ethanol when traveling at elevation. Ethanol has a much lower boiling point than straight gas (175 degrees vs. 200). AND, if you do get fuel boiling off, the hot ethanol is what trashes the paint next to the fuel filler. And running higher octane means you have more alcohol in the tank, which boils at a lower temp than gas - higher octane is NOT a good thing because of that.

For heat issues - drive the truck for a while, get it up to highway speed, good and warm. Then touch the metal part of your shifter, and the floor mount for your passenger rear seat. If they are more than just a bit warm, hot to the touch you probably have an issue with too much heat under the truck contributing to your fuel issues.

 

[8lifgr8]

How much is the intake vsv? I probably should just get that too.

Is there a way to get techstream for under a mortgage payment that isn't Chinese virus laden?