Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen? (1 Viewer)

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I would contend 85 is probably ethanol free at many/most pumps even if not advertised. As Pshkaat alluded to, base fuel @ 85 (87 depending on market) does not have the additives (including ethanol) that many suppliers use to boost the octane rating.
 
I've been dealing with this problem for years now. I have an 07'. This is the first time I've been able to find any info on it. I've been to a handful of mechanics and nobody can diagnose the problem. Once the fuel starts boiling I can't shut the rig off or I won't be able to start it back up until the fuel cool. I live in Vegas and as soon as the summer temps get rolling I start having issues. I wasn't out long at all yesterday and I had to get a LYFT home from lunch because my rig wouldn't start. Right now it's 115 degrees out and I can't even run a couple errands without worrying about it. I've changed the fuel cap and charcoal canister without any improvement. I'm going to give my mechanic this thread and see if he can run a few tests with some more focus this time. I love my rig, but this is so frustrating.
 
I've been dealing with this problem for years now. I have an 07'. This is the first time I've been able to find any info on it. I've been to a handful of mechanics and nobody can diagnose the problem.

The pain and fear is real. A lot of us have these issues. Seems like it was a huge miss by Toyota somehow. Same issues in the FZJ80 but they never seemed to lock up. I'm curious what the evap if any system is like in the Middle East-spec 100s?
 
The pain and fear is real. A lot of us have these issues. Seems like it was a huge miss by Toyota somehow. Same issues in the FZJ80 but they never seemed to lock up. I'm curious what the evap if any system is like in the Middle East-spec 100s?
That's a good question.
 
So I just looked over all my vacuum hoses in the engine bay and all of them are in great shape except for the two that were under the engine cover (another reason to remove it) It's these two:

Screen Shot 2020-07-13 at 12.53.03 PM.png

Above: I believe this is part number 2382950070 anyone confirm?

Screen Shot 2020-07-13 at 12.54.17 PM.png

Above: Can't find this part? Anyone know?
 
I think it would be helpful for someone who's experiencing this to take some footage with a FLIR camera. Temperature seems to be a major contributing factor and I suspect areas of the system are overheating. The exhaust is an obvious source of heat, but I think we could learn a LOT with some thorough FLIR footage of the fuel lines and tank. I bet we'll see some unexpected hot/cold areas. Perhaps that could help ID the issue parts.


So I just looked over all my vacuum hoses in the engine bay and all of them are in great shape except for the two that were under the engine cover (another reason to remove it) It's these two:

View attachment 2370792
Above: I believe this is part number 2382950070 anyone confirm?

View attachment 2370793
Above: Can't find this part? Anyone know?

Yes, I show that as correct. The part number for the other hose assembly is this, I think: 17341-50110
1594671542645.png
 
The pain and fear is real. A lot of us have these issues. Seems like it was a huge miss by Toyota somehow. Same issues in the FZJ80 but they never seemed to lock up. I'm curious what the evap if any system is like in the Middle East-spec 100s?
I've searched around on PS before and I don't believe the M.E. spec 100's have the emissions systems, at least similar to North America.
 
I've been keeping track of temps all over the fuel circuit for the past few weeks with IR gun. Granted IR gun won't tell me how hot it is inside the pipe/hose but it does indicate to me heat soak hotspots along the way. It would seem that there's some heat soak to the return line cross the back side of the engine- I dont think its enough to warrant moving the line-possibly wrapping it with silicone tape or reflective wrap like you have there might make a small difference. But in my checking so far, the temps on that line and fittings haven't been substantially different form other sections of the fuel circuit as it makes its way from one side of the engine to the other. Ive been checking temps at inlet fitting at fuel filter, base of pulsation damper, banjo bolt at front DS crossover, banjo bolt and PS cross over terminus, FPR inlet, FPR outlet, PS where rear crossover turns to steel pipe, DS where it turns back to rubber and last where rubber meets the steel return line on the fenderwell. I haven't seen more than a few degrees difference between inlet and return through out the entire circuit. All temps being in the 135 F range (+/- 4). This is testing in +90F (intake temps 110F +/-) ambient temps city driving for 1hr.

I revert to my belief that the health of the fuel pump & FPR have more impact on heat soak than fuel lines across the engine. Not saying the proximity to the cat doesn't have a contributing effect, or where the Y-pipe joint meets the muffler pipe ( an area prone to exhaust leak and heating the front side of the tank). Just have to make sure the pump is strong and moving the fuel as it heats up. Old pumps get weak, more affected by heat and pump pressure and delivery drops-fuel heats up more.

1. Your IR temp gun is ok for gathering data but unless you can use it many times per drive per day as well as watch it change as you drive, then it's not really telling you anything. This problem's #1 cause is time, #2 is time spent at low RPM/idle. Because it's heatsoak over time of course all of the points you measure will be within a few degrees at any given time.

2. I have a new fuel pump, new FPR, new fuel damper, new filter, replaced tons of lines, rebuilt my charcoal canister, new radiator, new thermostat, new coolant hoses, new COPs, new plugs, new exhaust, etc etc.

I have done the heat shield mod.

I have used all types of fuel.

I can tell you right now that moving my return line up on to the firewall is the only thing that I did that had a measurable effect on the fuel temperature.


mmPyJyl.jpg


OEM fuel pressure regulator: Amazon.com: Genuine Toyota Parts - Regulator Assy, Fuel (23280-50050): Automotive
OEM fuel pump: Amazon.com: Denso 951-0003 Fuel Pump: Automotive
OEM fuel filter: Amazon.com: WIX Filters - 33875 Fuel (Complete In-Line) Filter, Pack of 1: Automotive
OEM fuel pulse damper: Amazon.com: Toyota 23270-50011 Fuel Pressure Pulsation Damper Assembly: Automotive


Replaced the heatshield with black slightly larger so it fits over without cutting and looks a lil better: https://amzn.to/3iYSgfg

vy5qrJq.jpg


Just got back from wheeling this weekend again over 10k feet and fuel temperature was noticeably lower on the highway up and it took longer to heat up than I was expecting. Maximum temperature was about 5-10F lower than I expected based on conditions. The highest I saw was 120F during the hottest part of the day (88F) and it was 110-113F for most of the day before that (70-80F ambient).

2g9J8Vm.jpg
 
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I assure your 189 to 205f indicates something not to factory specs. 205F should only be seen in the most demanding, hot OAT and loaded condition. Even then something is not right. 205F and your CAT will be very hot. I'll take a look at your rig, anytime you'd like to stop by. Please wear a mask (covid BS) here, I will also.

We're thinking along the same lines. That damage is cause by the condition over time. That the fuel shut off valve on vapor return line, may be getting stuck. But looking at parts diagrams in PQ. I do not see this shutoff valve after 02-. Those have CC in back and we may need to approach differently. But first all things under hood need to be at spec regardless of year..


I was just driving my 00LX w/350K+ miles (Emerald) in stop and go gridlock.:
I've never notice fuel smell, before. But on this day I did, at end of 3 hours stop and go driving around and in Denver at 99F OAT. Traffic is worst than ever these days, with people avoid public transportation. So this was worst case driving. I open the gas cap and got ~3 seconds of hiss, then put cap back on. I then heard CC humming. Went back and released cap again, and got 1 second of hiss. So gas must have been boiling somewhat. The system did it's job. This coolant system is spot on, except old fan clutch, which seems okay (aged). BTW; It's my understanding, CC vents to atmosphere when engine off. That fuel vapor is sucked into intake when running.

I did not get temps and FT while driving that day. Bluedriver had given me a bata driver to test, and it failed. Darn!

I do have two things on Emerald, I've been wanting to do. That is have fuel injectors serviced by Chuck (FIS) and replace the old factory fuel pressure regulator.

Note: I have extensive service history on Emerald. I don't have first 100K mile out of canada Dealerships, but most all for last 250K miles. It is the longer/thickest service history I've seen. Never any mention of fuel issue of this topic, that can I recall. I take another look. But it spent time in many parts of North America, and last few year in Ft Collins foothills at about 6,500 feet. It was a good climb on slow road too, where it lived. All back top and no shade. So it had, hot, long slow drive daily in the summer.
Would be happy to let you check out my rig. I'm in C Springs area. Just drove back today from denver car temp outside read 91 to 99 degrees. I hit 203 on my engine coolant temp per bluedriver but this was with car full of family/gear and was in 4th gear going up that hill just south of lone tree, once we created hill the 203 temp dropped within 10 seconds to 190 so I assume the system did something to correct. Again 87 octane and no ethanol fuel and was full tank. Normally would have at least been venting when got home and hearing that sound of pressure against gas cap but was silent and no gas fumes expelling either. Attaching screenshots at end of drive from bluedriver and the record it saved too. Fuel trim/O2 sensor data should be in there.

Screenshot_20200713-131548_BlueDriver.jpg
 

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The heat shield works. if you have an 06-7 get a new pump denso 950-0210, just because, and make a shield. ASsuming all your other intake/fuel/plumbing/exhaust systems are top notch.
I had mine out recently for exhaust work.

here's decent pics

the middle east 100 has cats in some places and not in others from what I've looked at. Most I've seen look exactly like NA units. I'm sure way less stringent on regs though.

shield1.jpg


shield2.jpg


shield3.jpg
 
Has anyone tried replacing the evap valve I posted to solve this?

95 degrees and fluctuating elevation from 5k to 11k on and off all weekend. Popped the gas cap a few times and not even a hiss of pressure being released.

I even "topped up" the tank to see if I could duplicate others issues.
 
Has anyone tried replacing the evap valve I posted to solve this?

95 degrees and fluctuating elevation from 5k to 11k on and off all weekend. Popped the gas cap a few times and not even a hiss of pressure being released.

I even "topped up" the tank to see if I could duplicate others issues.
I checked that part seems to be valid part of convo for 99-02...which leaves me out here with an 03. My part here is part of the CC that moved to rear of vehicle near spare whereas I think your CC and valve in question here are in engine bay?
 
I checked that part seems to be valid part of convo for 99-02...which leaves me out here with an 03. My part here is part of the CC that moved to rear of vehicle near spare whereas I think your CC and valve in question here are in engine bay?

There is a valve for both eras, the earlier models is in the engine bay, later models on top of canister in my understanding.

To me the gas temps are a contributing factor sure, but the fact the system isn't releasing pressure is why it's boiling out if the tank.

Im curious on if anyone with the earlier models has had success with the valve like I have.
 
There is a valve for both eras, the earlier models is in the engine bay, later models on top of canister in my understanding.

To me the gas temps are a contributing factor sure, but the fact the system isn't releasing pressure is why it's boiling out if the tank.

Im curious on if anyone with the earlier models has had success with the valve like I have.
By any chance, do you have the part number for the valve you're talking about? I'm currently searching your posts for it, but since you're online maybe you'd help a brother out? 😃
 
By any chance, do you have the part number for the valve you're talking about? I'm currently searching your posts for it, but since you're online maybe you'd help a brother out? 😃
Nevermind. I found your post. Thank you!
 
Has anyone tried replacing the evap valve I posted to solve this?

95 degrees and fluctuating elevation from 5k to 11k on and off all weekend. Popped the gas cap a few times and not even a hiss of pressure being released.

I even "topped up" the tank to see if I could duplicate others issues.
Here is the part that was replaced at 152k on my cruiser. Dealership noted a PO441 code in their memo line. I have to imagine sometimes the computer catches this and sometimes it doesn't.

Vapor Canister Purge Solenoid. Dealership called it the "Evaporative Emissions System Vent Valve"

#9091012268


It looks like a fairly easy part to verify serviceability on. The question is, what is the trigger for the PO441 CIL code?

Nice, i searched threads on p0441 and not many out there when i was first getting it as a new owner of this 100 and most just said new gas cap or evap canister. p0441 appears to be a common code used in many vehicles and many hits in google for this.

So after googling some more i just settled in tighting gas cap really good and it hardly comes on now. Probably been like 6 months.

The gas smell only happened a few times while in desert and altitude change off roading.

I always get the p0441 every couple of months randomly.

Here are some sites on p0441 just googling notice how a symptom is strong fuel odor.


 
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The valve being faulty is the only thing that makes sense. Getting the fuel cooler is just a bandaid fix. These things are designed to run in a broad range of outdoor conditions and should be able to handle hot fuel. Has to be a problem with valve or problem with what controls valve to purge pressure.
 

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