100 Caught fire & gas tank venting concerns

[kickitrootdown]

Got a new one for you all. Had my tank boil and spew out of the filler cap after rapidly climbing in elevation last summer. Found some faulty wiring that fried the sender and instrument cluster and it has been fine since repairing the wiring. Cue this weekend: again climbing rapidly (SLC valley to Snowbird, about 4,200' to 8,000' over 10 miles or so). Started getting a burning plastic smell in the cabin, pulled over, popped the hood and vented the gas cap (very little hissing so the tank, I don't think, was boiling). Nothing apparent coming from the engine compartment, definitely not the plastic smell. No leaks underneath. I was almost to the top so we finished off the drive, gave it a couple hours to rest, then drove home. Got some fuel smell (not plastic) on the way back so I thought maybe something happened to the nylon fuel line (which I had just repaired a couple months ago). Pulled the back seats out, opened up the hatch to find this:

I don't know how or what, but I got it towed to the rock stars over at State Automotive in Midvale so we'll see what happens. The housing on the wire connector that connects to main driver-side harness (which is still in perfect apparent condition) is in pretty brutal shape, but good lord, the assembly MELTED. My gut says that it is still electrical that is shorting out from getting too hot and just zapping the fuel pump/sender assembly, but we'll see. Fingers crossed for the issue to be downstream related.

 

[2001LC]

You may have a rodent issue. The yellow/red wire looks chewed, at point where sheathing starts again. But very hard to see.

 

[KFunk740]

For the original fire concern:
It could've just been a rusty/leaky fuel line that caught a spark somehow. I had one leak on my '99 quite a bit right after a bought it, at a bend in the line near the left rear wheel. I got a CEL first (P0171, lean), and smelled the fuel when I got out of garage. It was dumping quite a bit, couldn't imagine how much it dumped while on the road. Luckily, just patched up the line and the CEL went away, and no issues.

 

[abuck99]

Got a new one for you all. Had my tank boil and spew out of the filler cap after rapidly climbing in elevation last summer. Found some faulty wiring that fried the sender and instrument cluster and it has been fine since repairing the wiring. Cue this weekend: again climbing rapidly (SLC valley to Snowbird, about 4,200' to 8,000' over 10 miles or so). Started getting a burning plastic smell in the cabin, pulled over, popped the hood and vented the gas cap (very little hissing so the tank, I don't think, was boiling). Nothing apparent coming from the engine compartment, definitely not the plastic smell. No leaks underneath. I was almost to the top so we finished off the drive, gave it a couple hours to rest, then drove home. Got some fuel smell (not plastic) on the way back so I thought maybe something happened to the nylon fuel line (which I had just repaired a couple months ago). Pulled the back seats out, opened up the hatch to find this:

View attachment 2005516

I don't know how or what, but I got it towed to the rock stars over at State Automotive in Midvale so we'll see what happens. The housing on the wire connector that connects to main driver-side harness (which is still in perfect apparent condition) is in pretty brutal shape, but good lord, the assembly MELTED. My gut says that it is still electrical that is shorting out from getting too hot and just zapping the fuel pump/sender assembly, but we'll see. Fingers crossed for the issue to be downstream related.

For the top of the tank to become hot enough to melt the plastic tank housing and the fittings being what appears to be burned- is very serious. Theres nothing under the melted portion that would create this so either you had a flash fire, or some heat transfer via exhaust: like a hot exhaust leak from the top of the muffler, or connection/fittings. Also looks like you have a broken wire, and other wires were spliced and heat shrinked?

 

[savirc]

You may have a rodent issue. The yellow/red wire looks chewed, at point where sheathing starts again. But very hard to see.

X2 looks like rodent hair left over around electrical tape.

 

[Jfoofighter16]

Please check my post on this. I replaced CC, VSV valve and gas cap all OEM and still has gas pressure/hot tank/boiling on hot day concern as others have posted here....still had the problem today the day after fixing the 3 items last night. If you see my post, you'll see that I went to replace fuel pump.next to discover some fuel corrosion on floorboards, not by the O cover for fuel tank/pump. Dealer just advised me my tank was expanding to dangerous point and starting to break at seams (though I've never noticed a leak and these things dont get great gas mileage as is so cant really say I was losing fuel too fast or not!!) Anywho my whole tank is now getting replaced and the rubber O ring seal for tank.

If others have same problems I highly advise getting your tank checked out first. Mine was jacked up and too many similar posts out there with no resolution and guys just hitting the mtns with tanks 3/4 full to try and minimize pressure when you could still be driving around with you tank about to be a bomb under you if my problem is same as others. I only say this bc I see too many guys replacing CC with seemingly no results and see no one mentioning gas tank itself and getting it legit inspected at dealer.

Just my $0.02, I'm just hoping this stops the problems and gives me peace of mind for safety was planning on hitting the trails with fam in tow on this thing!

 

[suprarx7nut]

Please check my post on this. I replaced CC, VSV valve and gas cap all OEM and still has gas pressure/hot tank/boiling on hot day concern as others have posted here....still had the problem today the day after fixing the 3 items last night. If you see my post, you'll see that I went to replace fuel pump.next to discover some fuel corrosion on floorboards, not by the O cover for fuel tank/pump. Dealer just advised me my tank was expanding to dangerous point and starting to break at seams (though I've never noticed a leak and these things dont get great gas mileage as is so cant really say I was losing fuel too fast or not!!) Anywho my whole tank is now getting replaced and the rubber O ring seal for tank.

If others have same problems I highly advise getting your tank checked out first. Mine was jacked up and too many similar posts out there with no resolution and guys just hitting the mtns with tanks 3/4 full to try and minimize pressure when you could still be driving around with you tank about to be a bomb under you if my problem is same as others. I only say this bc I see too many guys replacing CC with seemingly no results and see no one mentioning gas tank itself and getting it legit inspected at dealer.

Just my $0.02, I'm just hoping this stops the problems and gives me peace of mind for safety was planning on hitting the trails with fam in tow on this thing!

Replacing the tank seems a good idea, but shouldn't the gas cap and CC vent have pressure reliefs that avoid a build up of that sort of pressure? Seems like folks with these recurring problems might want to consider using a vented gas cap (despite what the local emissions regulatory rules might have to say about it...).

 

[savirc]

Replacing the tank seems a good idea, but shouldn't the gas cap and CC vent have pressure reliefs that avoid a build up of that sort of pressure? Seems like folks with these recurring problems might want to consider using a vented gas cap (despite what the local emissions regulatory rules might have to say about it...).

A vented gas cap will throw a CEL

 

[gatormark91]

My venting was caused by a hole in the top of my muffler heating up my tank.

 

[Jfoofighter16]

Dealer has mine now. They are thinking tank went bad and was pressurizing from using ethanol fuel...they even asked me if I knew if e85 was ever run in it! I'm going to have them look at electrical lines leading to fuel tank and exhaust system to see if something was causing this heat up to where my tank was bulging. Will report back with outcome on my end from dealer...I'm already gonna be in for 1500.00 on new tank. I wonder if that comes with new tank vacuum valve. That was only piece in the equation I didnt fix, as I had done CC, OEM cap, vsv valve at engine manifold but not the tank valve as that was beyond what I was willing to do DIY.
Either way since the rig is an 03 with 184k on it the tank has already seen too much damage from whatever flaw/evap system failure had been occurring...I live in c springs at about 7k ft and was experiencing the gas fumes/smell on 80 degree plus days in town, now even pushing the rig in the mtns yet....thank God I hadnt. Have 4 little kids, after reading this thread and experiencing my issues I'm second guessing buying an LC almost. And I really love everything else about the rig but the risk of my rig exploding/going down in flames is just unacceptable for me. Big T needs to do something about this!

 

[2001LC]

@Jfoofighter16 Is Dealership thinking boiling issue was solved and your now dealing just venting gas vapor from bad seams/seal of gas tank?

 

[Jfoofighter16]

I have yet to get that answer from them. My gut tells me something is wrong with exhaust system/catalytic converter or with the electrical hookup to fuel tank. I don't think bad fuel/ethanol residues in the tank would have been causing the pressure buildup and boiling fuel unless I just dont know something here. Another reason I say this is bc when I was about to replace fuel pump before bringing tondealwr yesterday I noticed my floorboards were much hotter right over my cat than the warmth over the gas tank so I think that is where the heat is coming from. I will be having dealer check that out. Worried i may have to scrap the rig if they start finding too many things wrong at this point. Worst part is this rig looked clean tested fine at a local shop when I bought it in April this year before summer kicked in. Now I'm kicking myself!!

 

[suprarx7nut]

Dealer has mine now. They are thinking tank went bad and was pressurizing from using ethanol fuel...they even asked me if I knew if e85 was ever run in it! I'm going to have them look at electrical lines leading to fuel tank and exhaust system to see if something was causing this heat up to where my tank was bulging. Will report back with outcome on my end from dealer...I'm already gonna be in for 1500.00 on new tank. I wonder if that comes with new tank vacuum valve. That was only piece in the equation I didnt fix, as I had done CC, OEM cap, vsv valve at engine manifold but not the tank valve as that was beyond what I was willing to do DIY.
Either way since the rig is an 03 with 184k on it the tank has already seen too much damage from whatever flaw/evap system failure had been occurring...I live in c springs at about 7k ft and was experiencing the gas fumes/smell on 80 degree plus days in town, now even pushing the rig in the mtns yet....thank God I hadnt. Have 4 little kids, after reading this thread and experiencing my issues I'm second guessing buying an LC almost. And I really love everything else about the rig but the risk of my rig exploding/going down in flames is just unacceptable for me. Big T needs to do something about this!

You should definitely file a complaint on the link posted previously. NHTS or something like that.

 

[Jfoofighter16]

You should definitely file a complaint on the link posted previously. NHTS or something like that.

Will definitely be doing that!

 

[2001LC]

I do inspection all the time. I find more stuff than anyone I know of on the 100 series. But really, I don't think I would have found this issue while inspecting, unless I smelt fumes. I'll be looking at gas tank in future inspection as much as I can!

 

[gatormark91]

Will definitely be doing that!

Bad/clogged cat or something causing that bank to get too much fuel dumped in it (wonky O2 sensor, vac leak) will cause a cat to get red hot.

You don't need a recall. You need to fix whatever 15-20 year old part is causing too much heat under your truck. That's why your tank and floor are getting too hot. Check the fuel trims and use a pyrometer to see the temp of each cat. Also, might drop your muffler and check for pinholes on top. If there is even a whisper of exhaust sound anywhere under the truck, it can trap enough heat to cause a fuel boiling issue.

 

[gatormark91]

Bad/clogged cat or something causing that bank to get too much fuel dumped in it (wonky O2 sensor, vac leak) will cause a cat to get red hot.

You don't need a recall. You need to fix whatever 15-20 year old part is causing too much heat under your truck. That's why your tank and floor are getting too hot. Check the fuel trims and use a pyrometer to see the temp of each cat. Also, might drop your muffler and check for pinholes on top. If there is even a whisper of exhaust sound anywhere under the truck, it can trap enough heat to cause a fuel boiling issue.

And unless your tank has actually broken open or is leaking, don't replace it. If it holds gas, and you fix your heat problem, the tank is probably fine to keep using.

As far as the Toyota dealer figuring this out, good luck with that. I'd make a safe bet they have no clue, will not figure this out, and will keep getting you to throw money at it and charging you $$$$ until you give up and go away. Fix the heat problem, fix the fuel boil, done.

 

[Jfoofighter16]

Definitely hear what your are saying and agree something is up with the cat/associated system. I am just surprised to see posts where this had occurred early on in vehicle ownership on 100 series, I totally agree a 15+ year old vehicle will have parts that fail, it just seems that folks at several age/mileage ranges are seeing same/similar issues.

 

[guardcompany]

I had some boiling issues at HIH9 this year as did a couple other guys even with 1/2 tank.

One of the days we were out on the trails ALL day until 7pm and my floorboard got really really warm. So I'll be chasing this too.

 

[Jfoofighter16]

I had some boiling issues at HIH9 this year as did a couple other guys even with 1/2 tank.

One of the days we were out on the trails ALL day until 7pm and my floorboard got really really warm. So I'll be chasing this too.

Yeah I wouldn't mess around my tank was not deemed salvageable at least at dealer. I'm gonna try to see if I cant take a look tomorrow since they are waiting on new tank to show up as is.