Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen? (2 Viewers)

[Pskhaat]

Anecdote: took my 2 100s for a circumtour of canyonlands at 580 miles off road. Hot, slow, at angles, etc. Both of the 100s get the smell.

Almost the entire trip (with addl 80liters per vehicle) we did with non ethanol. At no time over 6 days did we ever get the smell.

Filled back up in Monticello and decided to keep it now on the cheap. Smelling by Moab. Coincidence?

 

[saucebox]

.

(Posted completely unrelated information in the wrong thread. Sorry guys.)

 

[Pskhaat]

.

(Posted completely unrelated information in the wrong thread. Sorry guys.)

I was gonna ask you more. Where did you end up posting?

 

[saucebox]

I was gonna ask you more. Where did you end up posting?

In the "What did you do to your 100" thread. Our group was somewhat near Canyonlands and that reminded me of the damage.

 

[cskidz99]

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.


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

Wow, that's a lot of great info! Thanks @2001LC ! It sounds like I've got a lot more items to inspect. About a year ago I had the intake system cleaned at a Toyota dealership (MAF, throttle body, injectors), spark plugs replaced, trans fluid and diff oil changed, so I think those items should be good. I also clean the battery terminals and replace the air filter at least every 5k miles when I do the oil change, and I just cleaned the MAF again for good measure about a month ago.

The other PM items you mentioned I still am very interested in doing, especially since I don't have any verifiable record of the last time they were done, if ever. Most important being cleaning the rad fins, it sounds like! (I need to get myself one of those 90deg powerwasher nozzles.) I've done a lot of deep water crossings and can pretty much guarantee there is junk stuck in there.

I was able to fill the coolant today (I ordered a special funnel for that purpose; was waiting on it to arrive), and it was about 2.5Q low. I don't know how much is in the coolant system total, but that seemed like a lot of fluid to be missing! Haven't seen any evidence of coolant leaks anywhere, so not sure how it got to be like that. I'm going to watch carefully to see if any manifest themselves now that it's full again. I'm hoping getting the coolant levels back to spec will do a lot to help the fuel boiling issue.

Also, I've downloaded the Blue Driver app and I'm going to purchase the sensor so I can do some more logging of ECT and trans temp to make sure I'm not still quietly overheating.

@menancyandsam I ordered some heat wrap like what you used to shield the fuel lines, but I'm going to wait and see how much of a difference having the proper coolant level makes before I put it on. Even if I decide the issue appears to be solved after a few test runs, I still think I will put the wrap on then just for good measure since I have it now anyway. Certainly can't hurt.

 

[2001LC]

Wow, that's a lot of great info! Thanks @2001LC ! It sounds like I've got a lot more items to inspect. About a year ago I had the intake system cleaned at a Toyota dealership (MAF, throttle body, injectors), spark plugs replaced, trans fluid and diff oil changed, so I think those items should be good. I also clean the battery terminals and replace the air filter at least every 5k miles when I do the oil change, and I just cleaned the MAF again for good measure about a month ago.

The other PM items you mentioned I still am very interested in doing, especially since I don't have any verifiable record of the last time they were done, if ever. Most important being cleaning the rad fins, it sounds like! (I need to get myself one of those 90deg powerwasher nozzles.) I've done a lot of deep water crossings and can pretty much guarantee there is junk stuck in there.

I was able to fill the coolant today (I ordered a special funnel for that purpose; was waiting on it to arrive), and it was about 2.5Q low. I don't know how much is in the coolant system total, but that seemed like a lot of fluid to be missing! Haven't seen any evidence of coolant leaks anywhere, so not sure how it got to be like that. I'm going to watch carefully to see if any manifest themselves now that it's full again. I'm hoping getting the coolant levels back to spec will do a lot to help the fuel boiling issue.

Also, I've downloaded the Blue Driver app and I'm going to purchase the sensor so I can do some more logging of ECT and trans temp to make sure I'm not still quietly overheating.

@menancyandsam I ordered some heat wrap like what you used to shield the fuel lines, but I'm going to wait and see how much of a difference having the proper coolant level makes before I put it on. Even if I decide the issue appears to be solved after a few test runs, I still think I will put the wrap on then just for good measure since I have it now anyway. Certainly can't hurt.

Your low coolant, may have be from not been topped properly last service.

No special tools need to top coolant. While engine cool enough to remove radiator cap, I top with Toyota coolant. I top reservoir to high mark. Then simply bring engine to operating temp. Drive so I get up to ~2,500 RPM for ~10 minutes, with both cabin heaters on hot. Then let cool down over night, with front of vehicle high than rear (at minimum level). Than early in the morning before sun or air temp heats the vehicle/radiator/engine. I check under the radiator cap. I fill radiator to the neck. Than I repeat. I keep repeating, until I can't get more coolant into the 16 qt system. The cabin heaters should now blow very hot.

Make sure reservoir fill/draw tube is dropping straight to the bottom of reservoir and clear of obstruction. Replace rad cap and thermostat if not done.


Also make sure all vacuum hoses in good condition on and to engine. Most ever 100 series need most replaced by now.

 

[guardcompany]

Wow this thread has got into the weeds ha.

Just an update... I've ran some trails throughout our heatwaves here in southern california the last couple months and had zero issues. I haven't even got around to replacing the $500ish worth of EVAP parts I bought over the summer. I'm calling this issue fixed for me. I'll replace the EVAP stuff over the winter whenever I can find the time.

 

[saucebox]

Wow this thread has got into the weeds ha.

Just an update... I've ran some trails throughout our heatwaves here in southern california the last couple months and had zero issues. I haven't even got around to replacing the $500ish worth of EVAP parts I bought over the summer. I'm calling this issue fixed for me. I'll replace the EVAP stuff over the winter whenever I can find the time.

Without having backtracked...what did you do to fix?

 

[Whoareu2200]

Without having backtracked...what did you do to fix?

I WAS JUST BACKTRACKING ALSO LOL

 

[Whoareu2200]

 

[guardcompany]

There you go ^^

 

[saucebox]

All I have left is to wrap the fuel lines then, the rest of my list looks almost like yours (excepting front O2 sensors).

I attempted some Canyonlands trails a couple of weeks ago with regular 85 gas (usually run premium) and I've never had it worse. Even after all the other fixes. Silly me thought temps in the 70s would be OK. Fingers crossed.

 

[guardcompany]

All I have left is to wrap the fuel lines then, the rest of my list looks almost like yours (excepting front O2 sensors).

I attempted some Canyonlands trails a couple of weeks ago with regular 85 gas (usually run premium) and I've never had it worse. Even after all the other fixes. Silly me thought temps in the 70s would be OK. Fingers crossed.

Are you watching your engine temps? Curiously do see what you are running.

 

[saucebox]

Are you watching your engine temps? Curiously do see what you are running.

Busted...

I suspect slightly higher temps due to having all three Slee skids in place, but everything else has been OK. Not "I know exactly what the number is", but very consistent from places like Engineers Pass to Death Valley to scorching summers here ~5000ft. The trick is remembering to monitor things on wheeling trips (happens most frequently then) and I've just sucked at that so far.

 

[jerryb]

beating the dead horse.

If everyone could manage their fuel tank temp, none of this would happen.
Manage that and it will go away.

the RCA is that tank temps were too high, causing rail temps to increase beyond the capabilities of the car and the fuel composition.

 

[abuck99]

beating the dead horse.

If everyone could manage their fuel tank temp, none of this would happen.
Manage that and it will go away.

the RCA is that tank temps were too high, causing rail temps to increase beyond the capabilities of the car and the fuel composition.

Tend to agree.

Managing overall fuel tank temps however maybe not as easy as it sounds. If by "managing" you're implying affecting return line fuel temperatures with shielding and hose sleeves we've seen that's fairly easy to deal with, but what else could be realistically done to manage tank temps as they can also be affected by heat soak from pavement, exhaust system, etc?

 

[Live to Ski]

12v fans w temp switch in strategic places...

 

[Pskhaat]

12v fans w temp switch in strategic places...

I'm doing napkin maths in my aged brain right now and can't conclude that there would be enough heat exchange with that method.

Alas, I don't have alternative recommendations.

 

[jerryb]

maintenance, old parts, hotter parts now than 15 years ago when they were new. midpipe temps, flow rate of fuel pump, volume in tank, driving habits. maybe a 200 degree swing in the cat pipe solves or it induces it. Could be all sorts of stuff. Quick leakdown on the pressure side fuel pump check valve. Worse gas at station X than station Y. Ethanol content, excess water in fuel on ones that don't get driven much.
All the little things could add up to just enough over the limit. I don't know where the limit is.

The one thing I'm confident in saying is that I always have a 30-35 degree difference in fuel rail temp and ambient (while driving)
Does not matter how hot or cold it is outside. 100 gets me 130, 60 gets me 90. That's my number.
My other numbers are hotsoak key on rail temp less than 167 degrees (hottest I've seen) , and a 50 degree drop in rail temp at startup within 30 seconds, ambient temp dependent. More if it's colder out and less if it's hotter.
Those were summer temps, and going colder now it's the same. Right now it's still above 80. two weeks ago it was 60.

If anything deviates from that for me. I know something different is happening.

 

[jerryb]

get a temp gun and do some work. It's not too hard. Everyone needs their own baseline. To gauge with.