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

[Captramrod01]

I had this happen once and have since replaced fpr and the vsv for charcoal canister in engine bay on my 06. Seems most think it's truck running hot and keeping coolant Temps in line and heat shield is the "fix"

I take it you have not had a boiling issue since? I replaced my vsv valve not too long ago but have never touched my fpr.

 

[jerryb]

Before you buy a pump.
Observe the fuel pressure gauge while the engine runs and after shutting off the engine. Fuel pressure should hold to specs, while the engine is running, and after turning off the engine.
That's a 5 minute test in the FSM

no, the return line is not pressurized unless the open end in the tank already has pressure, and or if your fuel boiled in the return line at location X, then yes it will build back to the FPR. If the stock venting measures are overcome then yes there will be a rise in pressure in that line, and the tank.
(depending on how deep the level of fuel is and it's density and at what psig it overcomes that)=negligible.

This would be also (probably) why the rubber dispersion nipple blows off the end of return fuel dump line at the bottom of the tank/fuel pump.

antique cars have their own web boards also. They get in depth with carbs and todays fuel and coolling measures. There is great advice out there. search packard I think +fuel boiling and maybe ethanol.
if you want physics read below.

Ideal gas law, charles, dalton, gay lussac, boyle.

 

[2001LC]

I only had my front asfir skid on all my others were off at the time of hisssssssing.

Would you please restate; ECT temp and OAT, sun, night, overcast, smoke . Along with the before and after work you just stated to me in a PM.

 

[NearJetties]

Thought I’d provide additional anecdotal evidence.

I have a 98 and have been chasing an intermittent P0446 code (Evap control system vent malfunction). It’s been coming back on more frequently given recently—I assume because of the 90-95 degree heat for days on end. Most people seem to get a set of 3 codes.

Over time I’ve replaced all the vacuum lines, the gas cap, and the purge valve on the manifold (25860-50100) but the light keep coming back. Not immediately but eventually.

I replaced VSV (90910-12268) on top of the charcoal canister on Thursday. Left for a road trip the next day and put it through conditions that had been triggering it. Prolonged high temps, idling in a parking lot for extended periods to keep the pets cool. So far so good #fingerscrossed

Also, I don’t live and haven’t traveled to high altitude with the truck (yet) but we have traversed a mountain road 5 times with near empty and near full tanks since Thursday. It’s 5 miles with a quick up and down in the Adirondacks. It will make your ears pop a few times. That had set off the CEL once before.

I’ve only had a bit of tank pressure and no fuel smell except for a little bit when first opening the cap. After changing the last item and running through 3 tanks there seemed to be almost zero pressure. It was significantly cooler out though.

2.5 weeks ago I’m pretty sure I experienced the fuel boiling issue. maybe it was vapor lock but that’s not common on these.

It was 95+ and had been driving for 4 hours. Near or at sea level. Made a pitstop and kept the car idling in the parking space to keep the pets cool. Maybe for 15-20 mins tops. When pulling out of the spot the truck died. Fired up after a few seconds. Idled across the lot to get fuel and it died again. Again fired up after a few seconds. Both times it restarted but hesitated. Both times the wheel was turned almost all the way— maybe a coincidence but also could have been the additional power steering pump load. Once at the pump it kept kicking off the pump and had to be filled slowly. Hasn’t done it before or since. The CEL was already on with P0446 which had come one earlier in our trip. Pulled into a spot, popped the hood, let the truck cool, and cleared the code. Fired right up. Hopefully it doesn’t do it again since the P0446 problem seems to be solved but the two may also be unrelated. I didn’t think at the time to look at the ECT as the needle never moved.

-‘98 LC, 237k miles
-recent timing belt/water pump and cooling system service with the red Toyota juice by OTRAMM
-the truck is stock
-always get premium but with ethanol

I was surprised an hour long trail that I did recently didn’t set off the CEL. Nothing too extreme but definitely lots of fuel slosh. This was before replacing the purge vent and VSV. Temperature was around 90.

View attachment 2390953View attachment 2390954

Even though I haven’t had the fuel boiling issue again p0446 did come back so I ended up replacing the whole evap canister. As a result I have a few related parts for sale. Canister is free if you pay the ride.

For Sale - 100 series Evap Parts

 

[silver02accord]

I am going through the 100 series that caught fire thread but wanted to post this asap. I havent had the chance to read this thread it it's entirety but I will in the morning . One more update when on the fwy at 65 plus mph engine coolant temp was between 185 and 196, the outside temp was mostly over 100 deg up to about 113. We stopped for some lunch and shut off truck for 15 minutes. Fired up truck and waited at a drive through I noticed the temp when stopped climbed up to 213 deg. I am thinking to replace fan clutch asap as well. Recently replaced t Stat, new oem rad installed by lexus 2 years ago and new oem rad cap within last month. I should add I run 91 the po had ran 87(it sounds like) and I just had ran through a tank full of chevron injector cleaner which would have been diluted by this time due to 2 fuel tank refills on this trip. Please see my post below from other 100 series catching fire thread sorry for double post:

I am in page 5 of this thread but skipping ahead to post here. I have an 06 LX which I bought 2 months ago. This is the first extended road trip of more than 100 miles continuous. I have wheeled the car at approximately 4 to 6k elevation in Temps up to 100 deg no venting issue noted. Prior to this trip to bishop I replaced the fuel pump, fuel filter and gas cap with oem-the pump is a denso. I replaced thr pump this past week as PM and the truck fired right up. I did not replace fuel sock.

This past weekend I drove from San Diego(sea level) to Bishop approximately 7k elevation. This is about a 6 hour drive the outside temperature was about 90 to 108 degrees for most of the dive. I refueled twice, I am not sure of ethanol content. The most recent refueling was at about 4k feet approximately I filled the tank but did not "too off" beyond thr gas station auto shut off. We stopped at a friend's house at about 6k feet with no noticeable fuel smell. We then climbed another 1k or less to about 7k feet,this portion was mostly off road but speeds in the 20s with a few slow downs for obstacles.

I backed the car into parking spot shut off engine and noticed fuel smell. I looked at fuel tank door and saw visible vapors coming from fuel door. Here is a video link below. When the cap was shut vapors were still coming out. I opened the cap and thr fuel sounded like it was boiling. It took about 15 minutes to stop. The gas tank was approximately 3/4 full at this time.

When I bought the car the PO had maintenance records from Lexus. A cel threw 5 evap codes in March 2020. Per lexus tech: "isolated failure of leak detection pump. Tech recommends replace leak detection pump with vsv and related hoses" There was no cel when I bought it July 2020. I had the following codes come on in my ownership(p0441&p0445 gross leak and incorrect purge flow) I replaced fuel cap with oem and cleared the codes and the codes have not come back at all - it has been approximately 5 weeks.

Fuel door video-i have another showing fuel vapor with fuel door closed prior to opening it but don't think it's helpful.

This is all the details I can think of - maybe I should bite bullet and replace evap system as diagnosed?

@2001lc

Would you please restate; ECT temp and OAT, sun, night, overcast, smoke . Along with the before and after work you just stated to me in a PM.

Here is my original post I'm no good at "quoting" it on my phone.

It was about 5 or 6pm no smoke really. Sunny out. At this time I had asfir skid on and I was not monitoring ect when it hissed. I was checking ect on our ride home, hence the Temps reference below. I had just changed fuel pump. Fuel filter had previously been changed. Spark plugs and Coils had not yet been changed. I also was having a small pin prick spot of coolant on the water inlet tsat housing, but not a noticeable drop in the reservoir as line was marked. I'd classify it as eak

 

[silver02accord]

@2001lc

Here is my original post I'm no good at "quoting" it on my phone.

It was about 5 or 6pm no smoke really. Sunny out. At this time I had asfir skid on and I was not monitoring ect when it hissed. I was checking ect on our ride home, hence the Temps reference below. I had just changed fuel pump. Fuel filter had previously been changed. Spark plugs and Coils had not yet been changed. I also was having a small pin prick spot of coolant on the water inlet tsat housing, but not a noticeable drop in the reservoir as line was marked. I'd classify it as leak.

I am going through the 100 series that caught fire thread but wanted to post this asap. I havent had the chance to read this thread it it's entirety but I will in the morning . One more update when on the fwy at 65 plus mph engine coolant temp was between 185 and 196, the outside temp was mostly over 100 deg up to about 113. We stopped for some lunch and shut off truck for 15 minutes. Fired up truck and waited at a drive through I noticed the temp when stopped climbed up to 213 deg. I am thinking to replace fan clutch asap as well. Recently replaced t Stat, new oem rad installed by lexus 2 years ago and new oem rad cap within last month. I should add I run 91 the po had ran 87(it sounds like) and I just had ran through a tank full of chevron injector cleaner which would have been diluted by this time due to 2 fuel tank refills on this trip. Please see my post below from other 100 series catching fire thread sorry for double post:

I am in page 5 of this thread but skipping ahead to post here. I have an 06 LX which I bought 2 months ago. This is the first extended road trip of more than 100 miles continuous. I have wheeled the car at approximately 4 to 6k elevation in Temps up to 100 deg no venting issue noted. Prior to this trip to bishop I replaced the fuel pump, fuel filter and gas cap with oem-the pump is a denso. I replaced thr pump this past week as PM and the truck fired right up. I did not replace fuel sock.

This past weekend I drove from San Diego(sea level) to Bishop approximately 7k elevation. This is about a 6 hour drive the outside temperature was about 90 to 108 degrees for most of the dive. I refueled twice, I am not sure of ethanol content. The most recent refueling was at about 4k feet approximately I filled the tank but did not "too off" beyond thr gas station auto shut off. We stopped at a friend's house at about 6k feet with no noticeable fuel smell. We then climbed another 1k or less to about 7k feet,this portion was mostly off road but speeds in the 20s with a few slow downs for obstacles.

I backed the car into parking spot shut off engine and noticed fuel smell. I looked at fuel tank door and saw visible vapors coming from fuel door. Here is a video link below. When the cap was shut vapors were still coming out. I opened the cap and thr fuel sounded like it was boiling. It took about 15 minutes to stop. The gas tank was approximately 3/4 full at this time.

When I bought the car the PO had maintenance records from Lexus. A cel threw 5 evap codes in March 2020. Per lexus tech: "isolated failure of leak detection pump. Tech recommends replace leak detection pump with vsv and related hoses" There was no cel when I bought it July 2020. I had the following codes come on in my ownership(p0441&p0445 gross leak and incorrect purge flow) I replaced fuel cap with oem and cleared the codes and the codes have not come back at all - it has been approximately 5 weeks.

Fuel door video-i have another showing fuel vapor with fuel door closed prior to opening it but don't think it's helpful.

This is all the details I can think of - maybe I should bite bullet and replace evap system as diagnosed?

 

[menancyandsam]

Had Gas Boiling issue last summer.
Added a Heat Shield & wrapped my return fuel/vapor lines in the engine bay as well as some near the frame of the car.
Also changed the Fuel Filter.

Took her out yesterday 85f about the same elevation and experienced no boiling or fuel smell.

Difference in temp. was about 10 degree cooler this time and did not struggle as much on some trails as I did the time before. So not an exact scientific test.

But so far I'm pretty happy.

 

[Jcrider48]

Had Gas Boiling issue last summer.
Added a Heat Shield & wrapped my return fuel/vapor lines in the engine bay as well as some near the frame of the car.
Also changed the Fuel Filter.

Took her out yesterday 85f about the same elevation and experienced no boiling or fuel smell.

Difference in temp. was about 10 degree cooler this time and did not struggle as much on some trails as I did the time before. So not an exact scientific test.

But so far I'm pretty happy.

Hi,

Would you mind sharing some pictures of the heat shield and lines that you wrapped?

Did you make your own heat shield or purchase it? Can you provide a link for the wrap and shield if you purchased a shield?

Thank you!

 

[menancyandsam]

Hi,

Would you mind sharing some pictures of the heat shield and lines that you wrapped?

Did you make your own heat shield or purchase it? Can you provide a link for the wrap and shield if you purchased a shield?

Thank you!

I used heat resistance tape & a similar hook/loop sleeve in the places it was hard to wrap, Bought 2 rolls of the tape but I was sloppy in wraping so one roll might do.
Amazon product ASIN B000E267JCAmazon product ASIN B000E283S0
Here's pick of engine bay & Heat Shield purch. On amazon Amazon.com: M-D Building Products 56066 1-Feet by 2-Feet 22 ga Weldable Steel Sheet: Home Improvement

 

[Jcrider48]

I used heat resistance tape & a similar hook/loop sleeve in the places it was hard to wrap, Bought 2 rolls of the tape but I was sloppy in wraping so one roll might do.
Amazon product ASIN B000E267JCAmazon product ASIN B000E283S0
Here's pick of engine bay & Heat Shield purch. On amazon Amazon.com: M-D Building Products 56066 1-Feet by 2-Feet 22 ga Weldable Steel Sheet: Home Improvement
View attachment 2442262View attachment 2442268View attachment 2442269

Thank you! Did you wrap the fuel lines underneath anywhere?

 

[menancyandsam]

Yes about 6" on either side of the heat shield.

 

[2001LC]

Here's some 07LC w/133k heavy built (King coils w/30mm spacers, Iron bumpers, winch, compressor, rear lockers, rack, sliders, drawer, 5 Ko2's) ECT FT IAT numbers.

Report of 1 incident of fuel boiling in the mountains. Gas cap area was relatively clean.

176-186F OAT 70F sunny 3PM. Test drive, (IN).
154-174F OAT 41F over cast noon. Test drive after topping coolant.
189-196F OAT 36F sunny 2PM. Test drive after thermostat (OUT).

This one came to for AHC Globe R&R and adjusting sensors & T-bars. I took a short test drive, and notice ECT was only running low around 176 - 186F. That was second drive in which first lower. It took unusually long to reach these temps. First drive 5 miles in slow speed of 25-35 MPH. I ran in low gear at times running RPM up ~4K. Shut it down and drove again before hitting ECT 184F. The OAT was ~70F and sunny.
176-186F OAT 70F sunny. Test drive in.

I found coolant low, I add total of 2 qts to radiator and reservoir. Then took another test drive making multiple stop over 30 miles on another day. Seeing:
154-174F OAT 41F over cast. Test drive after topping coolant.

R&R OEM thermostat, Cap and clogged air filter. Took another drive. I'll note the radiator finds where and are clogged. OAT was to cold to for wet work of clean at this time. But on the heels of winter, not a big concern. On this drive I hit the HWY and did a burnout run. I ran at 5.2K RPM for 5 minutes at 60MPH (geared DN). ECT was steady at 196F. Once I dropped RPM down to ~3K taking speed up 75MPH in "D". The ECT jumped too 201F for 3 seconds then drop back to 196F quickly. Coming off HWY speeds dropping the temps drop more 189-194F.
189-196 OAT 36F sunny 2PM. Test drive after thermostat.

Although radiator fins dirty on all test drive. It seem to support the VVT engine does run hotter normally. The higher OAT temp on first day (IN), did yield higher ECT but below normal op temp of any year 100 series I've seen I'll do more work some warm day cleaning radiator and tuning engine. But considering the cooler OAT temps, dirty radiator fins less effect than a hot sunny day.

BTW I found thermostat jiggle valve more than ~12 degrees, from top. Which is within limit, but I shoot for 5 degrees. The thermostat blew it's inner seal. Cust., report 1 incident of fuel boiling in the mountains. Likely it overheated. Gas cap area was relatively clean. Likely due to air in coolant system, from improper topping.

 

[AlpineAccess]

Here's some 07LC w/133k heavy built (King coils w/30mm spacers, Iron bumpers, winch, compressor, rear lockers, rack, sliders, drawer, 5 Ko2's) ECT FT IAT numbers.

176-186F OAT 70F sunny 3PM. Test drive, (IN).
154-174F OAT 41F over cast noon. Test drive after topping coolant.
189-196F OAT 36F sunny 2PM. Test drive after thermostat (OUT).

This one came to for AHC Globe R&R and adjusting sensors & T-bars. I took a short test drive, and notice ECT was only running low around 176 - 186F. That was second drive in which first lower. It took unusually long to reach these temps. First drive 5 miles in slow speed of 25-35 MPH. I ran in low gear at times running RPM up ~4K. Shut it down and drove again before hitting ECT 184F. The OAT was ~70F and sunny.
176-186F OAT 70F sunny. Test drive in.

I found coolant low, I add total of 2 qts to radiator and reservoir. Then took another test drive making multiple stop over 30 miles on another day. Seeing:
154-174F OAT 41F over cast. Test drive after topping coolant.

R&R OEM thermostat, Cap and clogged air filter. Took another drive. I'll note the radiator finds where and are clogged. OAT was to cold to for wet work of clean at this time. But on the heels of winter, not a big concern. On this drive I hit the HWY and did a burnout run. I ran at 5.2K RPM for 5 minutes at 60MPH (geared DN). ECT was steady at 196F. Once I dropped RPM down to ~3K taking speed up 75MPH in "D". The ECT jumped too 201F for 3 seconds then drop back to 196F quickly. Coming off HWY speeds dropping the temps drop more 189-194F.
189-196 OAT 36F sunny 2PM. Test drive after thermostat.

Although radiator fins dirty on all test drive. It seem to support the VVT engine does run hotter normally. The higher OAT temp on first day (IN), did yield higher ECT but below normal op temp of any year 100 series I've seen I'll do more work some warm day cleaning radiator and tuning engine. But considering the cooler OAT temps, dirty radiator fins less effect than a hot sunny day.

BTW I found thermostat jiggle valve more than 5 degrees from top (~12 degrees). The thermostat blew it's inner seal. Cust., was report 1 incident of fuel boiling in the mountains. Gas cap area was relatively clean. Likely it overheated at take time. Likely in part due to air in coolant system, from improper thermostat install.

Hey Paul,

I had a thermostat do the exact same thing. It had 30k miles on it and 5 years old, and was an OEM t-stat. I had no problems until after I was trying to trace a small coolant leak and used my coolant vacuum tool to leak down test. I don't know if this created the issue but I have to assume it did.

I had no over-heating. It was the opposite as the gasket was caught in the thermostat and kept it stuck partially open. I ran my scanner and saw fluctuating OAT. Checked system to verify I had no air, and then pulled the thermostat and found this same issue.

I replaced the thermostat with a new OEM unit, vacuum-filled the system, and it went back to being flawless like it always has been.

You might ask your customer if they have had a coolant flush drain and refill done (or radiator replacement, etc.) on this vehicle in the last year. In my mind there are two options:

a. some t-stats have an inner gasket failure (very unlikely)
b. vacuum-charging a system with an older (fatigued) t-stat gasket is damaging that gasket and then the thermostat is finishing it off during heat cycling.

I spent a few minutes digging around looking for photos that I took of that thermostat when I removed it. I can't find them, but they look identical.

 

[2001LC]

Hey Paul,

I had a thermostat do the exact same thing. It had 30k miles on it and 5 years old, and was an OEM t-stat. I had no problems until after I was trying to trace a small coolant leak and used my coolant vacuum tool to leak down test. I don't know if this created the issue but I have to assume it did.

I had no over-heating. It was the opposite as the gasket was caught in the thermostat and kept it stuck partially open. I ran my scanner and saw fluctuating OAT. Checked system to verify I had no air, and then pulled the thermostat and found this same issue.

I replaced the thermostat with a new OEM unit, vacuum-filled the system, and it went back to being flawless like it always has been.

You might ask your customer if they have had a coolant flush drain and refill done (or radiator replacement, etc.) on this vehicle in the last year. In my mind there are two options:

a. some t-stats have an inner gasket failure (very unlikely)
b. vacuum-charging a system with an older (fatigued) t-stat gasket is damaging that gasket and then the thermostat is finishing it off during heat cycling.

I spent a few minutes digging around looking for photos that I took of that thermostat when I removed it. I can't find them, but they look identical.

I've seen this twice, recently.

First one, I also found the reservoir hose (cap) clogged. Both had low coolant level. First was near gallon low. I can see where pressure too high, it could blow the inner seal.

Your's happening after pressure test, is further clue of pressure blowing these. Coolant level low, engine runs hot, increasing pressure. Bad cap or plugged reservoir hose, will also increase pressure when temps exceed normal.

I'm looking through his well document service history (purchased new). If I find, he did have a test reported in history. I'll report back that info.

 

[cskidz99]

New member chiming in! First forum post! (Been anonymously lurking hard for about 2 years after purchasing my LC--this is my first 4wd vehicle am I'm hooked!) I've read this thread (and many, many others) top to bottom, and always stoked to learn more about my vehicle!

Previous to this I drove a White '00 Camry I4 (aka "The Wight Stallion") for 13 years and I flogged it harder offroad than a lot of people do their 4x4s (I know because I would pass them on the trails ), which included skipping in ignorance a lot of what I now know is crucial PM. I've been paying a LOT closer attention to this on the Landy. It has perhaps gotten a bit obsessive by some people's standards, but that's why we're all here, right?


Anyway, a little bit of background on the problem:
I drive an 06LC that has been having this fuel boiling issue for more than a year now. At first, the fuel boiling seemed to be causing the car to shudder and die when this boiling would get severe, usually only while crawling steep inclines in 4Lo above 9k feet elevation. (Very unsettling to have your vehicle suddenly die when you are out solo on top of a remote peak! It would always come roaring back to life like nothing happened if I let it sit for a few minutes, but I started losing confidence in the legendary Land Cruiser reliability.) However, after reading many forum posts and getting a local mechanic to confirm my suspicions, I determined the engine was dying because of a faulty fuel pump, which is apparently more common on the 06-07 Cruisers. I replaced the fuel pump myself and the car has not even shuddered once since. GREAT! But...

Even though the vehicle never full-on dies now, the fuel is still boiling under these same conditions, and the situation may be getting worse, as now I've noticed either evidence of leaking around the gas cap in the trail dust on the side of my vehicle or a very strong fuel smell entering the cabin when doing low-speed crawling in 4Lo even at very normal elevations (by Utah standards).


Most recent example:
I went 2 weekends ago to do Fins N Things and a few other easier Moab trails. About halfway through Fins N Things my passengers and I noticed a very strong fuel smell, so I stopped to give the Cruiser a break. Having read this thread, before running the trail I had filled up with Ethanol-Free gasoline, hoping that would tame the boiling issue. Since we smelt fuel, I assumed Ethanol-free gas hadn't made a difference. I got and checked the fuel tank expecting to hear the gurgling of boiling fuel, but the fuel actually wasn't boiling at all--zero pressure in the tank. Very odd.

Perplexed, we continued onward for a little while but opted to bail before the end of the trail just to be safe. The rest of the trails we did that weekend were easy enough that I only kept the car in 4Hi, and we never had the fuel smell return.

Based on the advice given in this thread, I wanted to make sure my cooling system fundamentals were in good order. Haven't been driving the Cruiser much since getting home, so I didn't look under the hood until yesterday. Hoses all look to be in great condition, as I believe they were replaced right before I bought it. Fan spins with some resistance when cold, but seems to have gotten much louder than it used to be when starting the car. Maybe there is something there? Coolant... uh oh! The coolant reservoir is completely empty and I can't see coolant in the radiator when I open the cap! That definitely needs to be addressed! According to the dash gauges, the car hasn't been overheating, even when fuel boils, but this obviously isn't ideal. I'll be taking care of that in the next few days and will report back on how much that helps the issue.


Questions:
@2001LC - what is this app you are using to log sensor data? (I have Techstream on an old laptop, but it is cumbersome, for me at least, to use for data logging. I want to document my problem with some hard numbers.)

@2001LC - Is the cooling fan on an 06LC supposed to spin when the engine is cold? Mine spins quite loudly, and the vehicle idles much higher than it is supposed to, at about 1200RPM. When I have been driving the car for a while it idles at a normal 600-800RPM.

@anyone - Have you had fuel smell in the cabin WITHOUT boiling in the tank?

 

[Jcrider48]

New member chiming in! First forum post! (Been anonymously lurking hard for about 2 years after purchasing my LC--this is my first 4wd vehicle am I'm hooked!) I've read this thread (and many, many others) top to bottom, and always stoked to learn more about my vehicle!

Previous to this I drove a White '00 Camry I4 (aka "The Wight Stallion") for 13 years and I flogged it harder offroad than a lot of people do their 4x4s (I know because I would pass them on the trails ), which included skipping in ignorance a lot of what I now know is crucial PM. I've been paying a LOT closer attention to this on the Landy. It has perhaps gotten a bit obsessive by some people's standards, but that's why we're all here, right?


Anyway, a little bit of background on the problem:
I drive an 06LC that has been having this fuel boiling issue for more than a year now. At first, the fuel boiling seemed to be causing the car to shudder and die when this boiling would get severe, usually only while crawling steep inclines in 4Lo above 9k feet elevation. (Very unsettling to have your vehicle suddenly die when you are out solo on top of a remote peak! It would always come roaring back to life like nothing happened if I let it sit for a few minutes, but I started losing confidence in the legendary Land Cruiser reliability.) However, after reading many forum posts and getting a local mechanic to confirm my suspicions, I determined the engine was dying because of a faulty fuel pump, which is apparently more common on the 06-07 Cruisers. I replaced the fuel pump myself and the car has not even shuddered once since. GREAT! But...

Even though the vehicle never full-on dies now, the fuel is still boiling under these same conditions, and the situation may be getting worse, as now I've noticed either evidence of leaking around the gas cap in the trail dust on the side of my vehicle or a very strong fuel smell entering the cabin when doing low-speed crawling in 4Lo even at very normal elevations (by Utah standards).


Most recent example:
I went 2 weekends ago to do Fins N Things and a few other easier Moab trails. About halfway through Fins N Things my passengers and I noticed a very strong fuel smell, so I stopped to give the Cruiser a break. Having read this thread, before running the trail I had filled up with Ethanol-Free gasoline, hoping that would tame the boiling issue. Since we smelt fuel, I assumed Ethanol-free gas hadn't made a difference. I got and checked the fuel tank expecting to hear the gurgling of boiling fuel, but the fuel actually wasn't boiling at all--zero pressure in the tank. Very odd.

Perplexed, we continued onward for a little while but opted to bail before the end of the trail just to be safe. The rest of the trails we did that weekend were easy enough that I only kept the car in 4Hi, and we never had the fuel smell return.

Based on the advice given in this thread, I wanted to make sure my cooling system fundamentals were in good order. Haven't been driving the Cruiser much since getting home, so I didn't look under the hood until yesterday. Hoses all look to be in great condition, as I believe they were replaced right before I bought it. Fan spins with some resistance when cold, but seems to have gotten much louder than it used to be when starting the car. Maybe there is something there? Coolant... uh oh! The coolant reservoir is completely empty and I can't see coolant in the radiator when I open the cap! That definitely needs to be addressed! According to the dash gauges, the car hasn't been overheating, even when fuel boils, but this obviously isn't ideal. I'll be taking care of that in the next few days and will report back on how much that helps the issue.


Questions:
@2001LC - what is this app you are using to log sensor data? (I have Techstream on an old laptop, but it is cumbersome, for me at least, to use for data logging. I want to document my problem with some hard numbers.)

@2001LC - Is the cooling fan on an 06LC supposed to spin when the engine is cold? Mine spins quite loudly, and the vehicle idles much higher than it is supposed to, at about 1200RPM. When I have been driving the car for a while it idles at a normal 600-800RPM.

@anyone - Have you had fuel smell in the cabin WITHOUT boiling in the tank?

I have had the fuel smell in my 07 with the windows open. When they are closed I haven't noticed it before.

Do you have any skid plates on your cruiser? I believe my issue started when I added skids. I recently insulated the fuel lines in hopes it solves my issue.

 

[cskidz99]

I have had the fuel smell in my 07 with the windows open. When they are closed I haven't noticed it before.

Do you have any skid plates on your cruiser? I believe my issue started when I added skids. I recently insulated the fuel lines in hopes it solves my issue.

Interesting...I don’t remember if I’ve smelt it with the windows closed, but I think either way it’s bad news.

No skid plates—vehicle is stock besides a Bluetooth unit for the stereo and 33in BFGs.

I’m going to try wrapping the lines in addition to the PM stuff I mentioned in my first post. Just ordered Velcro wrap from Amazon. Let me know how it works for you, I’ll do the same.

 

[menancyandsam]

Similar experience here. Seemed fixed after attaching
a heat shield to the cat shield which runs next to the fuel lines. Also heat wrapped the return fuel lines in heat tape.

 

[2001LC]

New member chiming in! First forum post! (Been anonymously lurking hard for about 2 years after purchasing my LC--this is my first 4wd vehicle am I'm hooked!) I've read this thread (and many, many others) top to bottom, and always stoked to learn more about my vehicle!

Previous to this I drove a White '00 Camry I4 (aka "The Wight Stallion") for 13 years and I flogged it harder offroad than a lot of people do their 4x4s (I know because I would pass them on the trails ), which included skipping in ignorance a lot of what I now know is crucial PM. I've been paying a LOT closer attention to this on the Landy. It has perhaps gotten a bit obsessive by some people's standards, but that's why we're all here, right?


Anyway, a little bit of background on the problem:
I drive an 06LC that has been having this fuel boiling issue for more than a year now. At first, the fuel boiling seemed to be causing the car to shudder and die when this boiling would get severe, usually only while crawling steep inclines in 4Lo above 9k feet elevation. (Very unsettling to have your vehicle suddenly die when you are out solo on top of a remote peak! It would always come roaring back to life like nothing happened if I let it sit for a few minutes, but I started losing confidence in the legendary Land Cruiser reliability.) However, after reading many forum posts and getting a local mechanic to confirm my suspicions, I determined the engine was dying because of a faulty fuel pump, which is apparently more common on the 06-07 Cruisers. I replaced the fuel pump myself and the car has not even shuddered once since. GREAT! But...

Even though the vehicle never full-on dies now, the fuel is still boiling under these same conditions, and the situation may be getting worse, as now I've noticed either evidence of leaking around the gas cap in the trail dust on the side of my vehicle or a very strong fuel smell entering the cabin when doing low-speed crawling in 4Lo even at very normal elevations (by Utah standards).


Most recent example:
I went 2 weekends ago to do Fins N Things and a few other easier Moab trails. About halfway through Fins N Things my passengers and I noticed a very strong fuel smell, so I stopped to give the Cruiser a break. Having read this thread, before running the trail I had filled up with Ethanol-Free gasoline, hoping that would tame the boiling issue. Since we smelt fuel, I assumed Ethanol-free gas hadn't made a difference. I got and checked the fuel tank expecting to hear the gurgling of boiling fuel, but the fuel actually wasn't boiling at all--zero pressure in the tank. Very odd.

Perplexed, we continued onward for a little while but opted to bail before the end of the trail just to be safe. The rest of the trails we did that weekend were easy enough that I only kept the car in 4Hi, and we never had the fuel smell return.

Based on the advice given in this thread, I wanted to make sure my cooling system fundamentals were in good order. Haven't been driving the Cruiser much since getting home, so I didn't look under the hood until yesterday. Hoses all look to be in great condition, as I believe they were replaced right before I bought it. Fan spins with some resistance when cold, but seems to have gotten much louder than it used to be when starting the car. Maybe there is something there? Coolant... uh oh! The coolant reservoir is completely empty and I can't see coolant in the radiator when I open the cap! That definitely needs to be addressed! According to the dash gauges, the car hasn't been overheating, even when fuel boils, but this obviously isn't ideal. I'll be taking care of that in the next few days and will report back on how much that helps the issue.


Questions:
@2001LC - what is this app you are using to log sensor data? (I have Techstream on an old laptop, but it is cumbersome, for me at least, to use for data logging. I want to document my problem with some hard numbers.)

@2001LC - Is the cooling fan on an 06LC supposed to spin when the engine is cold? Mine spins quite loudly, and the vehicle idles much higher than it is supposed to, at about 1200RPM. When I have been driving the car for a while it idles at a normal 600-800RPM.

@anyone - Have you had fuel smell in the cabin WITHOUT boiling in the tank?

Sound to me like you're overheating! That coolant system has been neglected. It is, so very important. If not in proper working order, is the number one killer of the 4.7 2UZ VVT or NON VVT..

I'll address water temp gauge first. When coolant level gets to low. We can get a false reading on the dash. If reservoir empty and you can't see in radiator. You are to low. The temp gauge reads liquid and sit high in the system. It does not read air temp well, from all we can tell. I've no doubt, from all you've said, you've been overheating. I'll bet if radiator has not been replace or fins cleaned. That it's fins are clogged.

You say hose looked good and you think PO replaced. Well, all hose need close inspection. Just popping hood, the untrained eye won't see much. If engine cleaned and sprayed with a shin, they all look good!. I must pull cover and feel, pinch and pull hoses in many cases, before I know for sure. In the 06-07 I'm changing, in most ALL. Both PCV hoses, the vane pump idle up vacuum lines. If one or more of the EVAP hoses, have ever been disconnected. They also very often need replacing. All vacuum lines need to be in very good working order. Vacuum leak can be in other area as well. They will cause engine to run lean (hot)

As far as fuel pump. You were smart to replace it. We have found many VVT with FP issue, which are very difficult to detect. I replace 5- 6 this year. I'm also seeing, the most bad FP, in rigs that battery post and clamps aren't cared for properly. It not a bad idea to replace fuel filter & FPR also. Also run cleaner through the gas. Like 44k or Chevron Techron are my go to's.

I use Blue Driver. It allows logging. I read, store and email the data from my iphone.

The VVT 06-07. Has a A.I. pump (air induction pump). This pump can be very loud. That is said to be indicative (loud) of pending failure, IDK. The A.I. runs for about 90 second on cold starts.

The cooling fan is not very loud on cold start up. RPM are high, on cold start up. Higher than non VVT. Then come down as engine warms. About 2 minutes after cold start. I take a rolled up paper sack or even my HP water, and stop the fan blade with either. As coolant warms the radiator, fluid in fan clutches moves. The heat from radiator, heat coil on front of fan clutch. This open valves in the FC. Cooling fan than gets loud, at this point. I can't stop the blade from spinning with my paper bag or HP water once loud. There are more test, Google it!

My bet; You are overheating and have been since before you first stated smell gas. You may also have fuel leak.

I lost track, of how many coolant services I did in just last three month. I start with cleaning radiator (all 3 rad.) fins. I end with cleaning fins again and again. Even after near 3 hours total time cleaning. I find they need even more cleaning. Dealership don't clean them. They replace them. Which is not bad bad Idea. Cleaning radiator fins is a PM nobody has been doing, that I've seen.

Radiator fins need cleaning! Alert Alert Alert

I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...

forum.ih8mud.com

I then tune the engine. This means stopping all vacuum leaks, R&R spark plugs, Denso COP spring, boots & seals. T-body & MAF CLN, Air Filter, PCV service. Battery terminals, LOF and anything I find in engine compartment that needs address.

Transmission fluid and level. All 04-07 are low if no fluid add. The factory fill was determined to be low, toyota has TBS out on this. Flushing all 12qts is always a good thing. I've done on 100 series, up to 350k miles. transmission always run cooler and shift smooth, with fresh fluid and porpely top.

Again get to the basics. 100 series, is a very reliable vehicle. But that does not mean adding a few personal touches, and just putting in gas and drive. They need proper PM.

So far, all but one that came to me this last summer, with this issues just of fuel boiling. Needed the basic put back inline. Except one.

I have had the fuel smell in my 07 with the windows open. When they are closed I haven't noticed it before.

Do you have any skid plates on your cruiser? I believe my issue started when I added skids. I recently insulated the fuel lines in hopes it solves my issue.

By skid are you referring to bell-pan.The one from transmission crossmember back?

 

[Jcrider48]

QUOTE="2001LC, post: 13461793, member: 28583"]
By skid are you referring to bell-pan.The one from transmission crossmember back?
[/QUOTE]

@2001LC
I'm referring to aftermarket skid plates. From the front bumper to the output shaft on the transmission.

I wish you were close so I could have you go through mine from top to bottom.

What device can I use to check the actual engine coolant?


Thanks for all the information you put into this post.