So this is interesting. How do you explain it? He was murdering the truck? Did not drop the gear when hauling the trailer up?
What you (or your parents) are doing differently?
Gas/Fuel vapors/fumes visible from gas door
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So this is interesting. How do you explain it? He was murdering the truck? Did not drop the gear when hauling the trailer up?
What you (or your parents) are doing differently?
Many Yota's have been returnless since the early 2000s. Most of the higher output engines seem to use return systems.
I bet they do know, but modifying the system (return fuel cooler probably) would cost money, and the bean counters decided it just wasn't worth it for the small percentage of US owners who would run into the issue.
This is my gripe with the argument against modifying anything because "the factory engineers know best." Between the engineers, the accountants, the sales experts, etc, the product that is sold is going to be a compromise to get the closest fit for the largest number of customers. Compare your own use case to what will fit the broadest customer base and you're likely to find some differences.
Taco2Cruiser
Crazy American Off Road
I’m sure Toyota had their reason for adding an entire fuel line to go all the way back to the rear of the truck. I just wish I knew why.
So after a while, I started looking at what was not a culprit to fuel boiling. That’s where I found that replacing emission system components or aftermarket parts was not it. I just saw too many instances on stockers that made me see it was a deeper issue.
To carry on the returnless or return setup that @vegasfj40 and @TeCKis300 mentioned. And, this is speculation on my part, I believe that is why Toyota keeps running return systems on higher output motors is for using the fuel to cool things like injectors (ever a port injected injector sits in a rather hot area). And when you are just all about reliability, I guess that makes sense.
At the end of the day, has anyone seen a failure from boiling fuel? Nope, the cruiser still runs great and will get you anywhere you still need. It’s terrible to be around one with raw fuel smell and damaged paint. Was that the compromise? I don’t think we’ll ever now.
Anyway… it sucks guys. It actually pisses me off so much I have my doubts on this not being an issue on the gen of cruiser/tundra motors still boiling fuel. I will be very interested to lay under a new tundra for 10 seconds and see if it is still return style or not.
This is where I will always fully admit that fuel boiling is an inconsistent thing. He was doing absolutely nothing different than what my parents do when towing.
So after a while, I started looking at what was not a culprit to fuel boiling. That’s where I found that replacing emission system components or aftermarket parts was not it. I just saw too many instances on stockers that made me see it was a deeper issue.
To carry on the returnless or return setup that @vegasfj40 and @TeCKis300 mentioned. And, this is speculation on my part, I believe that is why Toyota keeps running return systems on higher output motors is for using the fuel to cool things like injectors (ever a port injected injector sits in a rather hot area). And when you are just all about reliability, I guess that makes sense.
At the end of the day, has anyone seen a failure from boiling fuel? Nope, the cruiser still runs great and will get you anywhere you still need. It’s terrible to be around one with raw fuel smell and damaged paint. Was that the compromise? I don’t think we’ll ever now.
Anyway… it sucks guys. It actually pisses me off so much I have my doubts on this not being an issue on the gen of cruiser/tundra motors still boiling fuel. I will be very interested to lay under a new tundra for 10 seconds and see if it is still return style or not.
All the way to the rear? Where?
The inconsistency must be then down to some combination of factors. It can't be magic, it's physics. My take would be that these trucks are susceptible to the issue by design (as you point out), but there could be primary contributing factors (like improperly functioning EVAP/flooded charcoal canister), and secondary contributing factors (altitude, ambient temperature, gas quality). But ultimately it's the temperature of the fuel.
Fuel system with return is pretty common design I would think? Similar system on turbo Subarus (that run hot like hell). Never a problem with boiling fuel.
By the way, does the fuel pump run at varying duty cycles? Subarus have 3 duty cycles for their pumps, so the pump doesn't spin full speed when not needed (prevents wear and extra heat).
It may run great, but I think this is an extremely serious safety issue, and I am truly dismayed this has not been addressed by Toyota.
It pisses me off greatly, too. I became such a fan of this vehicle I bought another one. Maybe too soon, before really trying the first one in a variety of conditions.
Taco2Cruiser
Crazy American Off Road
To the rear, I mean back to the fuel tank, not necessarily all the way to the actual rear of the car.
I don’t feel the emissions equipment had anything to do with this. But again to stress what I think the issue is. Fuel cooling engine components. The 5.7 does that. But to think another hot running vehicle that doesn’t boil is relatable is not good for us. As we don’t know if those other engine designs use the fuel to cool components.
It is a serious issue, not doubt. I was j my saying that I find it fascinating that the engine does die from it.
Maybe we will figure it all out, but yes, it has put a really bad taste in my Toyota sauce that I have been eating since ‘01 with my first Toyota.
I do believe, that as a community, we will figure this out and all will be well. A reason why I felt it was time to dump this concept of mine on the group. Literally over a year I’ve been a working in this. I just didn’t want to join the conversation with thoughts and theories. But if more of us tank this idea, we will either find a solution for it, or prove that my thoughts are wrong. And we will get closer to a solution either way.
nwfl4runner
GOLD Star
Room underneath to add a Hilux in line fuel cooler?
Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?
DANGEROUS GAS PRESSURE BUILD UP IN GAS TANK! Why? What's going on? How can we fix this? Edited 3/15/25: Since first posting this thread. I've corrected many boiling fuel. By working in this order: Coolant system if first on the list, must be operating as designed. Which radiator fins cleaning...
forum.ih8mud.com
Sounds like we're onto some significant contributors to gas boiling.
In things like this, it useful to look at the overall system. We know that fuels today are more susceptible to boiling as they are blended with components that have higher Reid vapor pressures. This is well documented by the EPA allowing for a 10% higher pressure waiver for certain blends since 2012, particularly those that contain ethanol. So vehicles are dealing with expanded thresholds, perhaps after their designs.
Context and use case have a lot to do with this. Heat, altitude (and change in altitude), barometric pressure, extended crawling, etc.
I believe we agree that the temperature of the gasoline in the tank is a big variable. This should be considered as a system, with overall heat inputs, and radiant cooling output opportunities. With a 105 °F threshold for some lesser components of fuel to begin boiling.
We know there is hot fuel, with relatively low volume, being returned to the gas tank. (thanks @Taco2Cruiser ) There's a hot environment underneath the chassis, with really hot exhaust components nearby radiating on a broad surface area effecting a larger volume. Slow crawl not helping dampen localized temps in the engine bay and underchassis. The design of Cruisers tend to have their gas tanks tucked up higher than most every other truck and SUV, probably doesn't help here.
Guess what I'm saying is there may not be a single factor or variable. It's a stacked set of contributors. Every variable, however minor, can contribute or help. Every modification that effects airflow, may contribute or help. It may be that we can help fix things addressing some of the larger variables for some expanded situations. But there may be no single silver bullet here.
Looking at this as a system - I really doubt less fuel in the tank helps. I'd expect the opposite as a larger volume of fuel has more heat sinking mass. Though run long, slow, and hard enough, even that may not help as fuel volume inevitably is reduced after a long run with lots of heat soak.
So what solutions. It'll be interesting exploring a fuel cooler. I'd also take a closer look at heat sources around the tank. And make sure there's not so much armor effecting localized airflow. Perhaps other solutions, like heat wraps, or barriers. I used some of this heat insulation around my 12.5 aux tank, that could be useful on the main tank.
Amazon product ASIN B000E243AW
In things like this, it useful to look at the overall system. We know that fuels today are more susceptible to boiling as they are blended with components that have higher Reid vapor pressures. This is well documented by the EPA allowing for a 10% higher pressure waiver for certain blends since 2012, particularly those that contain ethanol. So vehicles are dealing with expanded thresholds, perhaps after their designs.
Context and use case have a lot to do with this. Heat, altitude (and change in altitude), barometric pressure, extended crawling, etc.
I believe we agree that the temperature of the gasoline in the tank is a big variable. This should be considered as a system, with overall heat inputs, and radiant cooling output opportunities. With a 105 °F threshold for some lesser components of fuel to begin boiling.
We know there is hot fuel, with relatively low volume, being returned to the gas tank. (thanks @Taco2Cruiser ) There's a hot environment underneath the chassis, with really hot exhaust components nearby radiating on a broad surface area effecting a larger volume. Slow crawl not helping dampen localized temps in the engine bay and underchassis. The design of Cruisers tend to have their gas tanks tucked up higher than most every other truck and SUV, probably doesn't help here.
Guess what I'm saying is there may not be a single factor or variable. It's a stacked set of contributors. Every variable, however minor, can contribute or help. Every modification that effects airflow, may contribute or help. It may be that we can help fix things addressing some of the larger variables for some expanded situations. But there may be no single silver bullet here.
Looking at this as a system - I really doubt less fuel in the tank helps. I'd expect the opposite as a larger volume of fuel has more heat sinking mass. Though run long, slow, and hard enough, even that may not help as fuel volume inevitably is reduced after a long run with lots of heat soak.
So what solutions. It'll be interesting exploring a fuel cooler. I'd also take a closer look at heat sources around the tank. And make sure there's not so much armor effecting localized airflow. Perhaps other solutions, like heat wraps, or barriers. I used some of this heat insulation around my 12.5 aux tank, that could be useful on the main tank.
Amazon product ASIN B000E243AW
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I'll jump in here, without reading thread. Sorry).
Very likely once a " fuel boiling" issues has occurred. It damages the EVAP system, without a code (DTC) popping up in tech stream. In some cases, it may actually be the EVAP that was damaged first, causing events.
Biggest issue I see causing engine to run too hot or overheating. Is coolant system not being properly PM'd. Number one issue in cooling system, being; We must clear/wash radiator fins. "See owners manual"
forum.ih8mud.com
The built rigs especially with aftermarket skids and belly pan, will run hotter and trap heat directing it to fuel lines and fuel tank. But our rigs seem (or most) to handle that extra heat okay. Provided all mechanicals and PM as it should be. But once event happens, it's hard to reverse, especially after 2002 model when charcoal canister was moved out of engine compartment to near spare tire.
"Thinking" (not yet proven that I've seen) by me, now is: Charcoal is getting into lines and possible valves of EVAP system, from damage charcoal canister. I hope to have two this fall that we can't correct by with tune and coolant service. To play with and see if I can find charcoal in lines, etc. Which means I'll not likely test, until summer of 2022.
forum.ih8mud.com
Very likely once a " fuel boiling" issues has occurred. It damages the EVAP system, without a code (DTC) popping up in tech stream. In some cases, it may actually be the EVAP that was damaged first, causing events.
Biggest issue I see causing engine to run too hot or overheating. Is coolant system not being properly PM'd. Number one issue in cooling system, being; We must clear/wash radiator fins. "See owners manual"
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
The built rigs especially with aftermarket skids and belly pan, will run hotter and trap heat directing it to fuel lines and fuel tank. But our rigs seem (or most) to handle that extra heat okay. Provided all mechanicals and PM as it should be. But once event happens, it's hard to reverse, especially after 2002 model when charcoal canister was moved out of engine compartment to near spare tire.
"Thinking" (not yet proven that I've seen) by me, now is: Charcoal is getting into lines and possible valves of EVAP system, from damage charcoal canister. I hope to have two this fall that we can't correct by with tune and coolant service. To play with and see if I can find charcoal in lines, etc. Which means I'll not likely test, until summer of 2022.
Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?
DANGEROUS GAS PRESSURE BUILD UP IN GAS TANK! Why? What's going on? How can we fix this? Edited 3/15/25: Since first posting this thread. I've corrected many boiling fuel. By working in this order: Coolant system if first on the list, must be operating as designed. Which radiator fins cleaning...
forum.ih8mud.com
Last edited:
I am curious to know how much pressure the system is designed to hold and how much does that raise the boiling point temperature? If fuel starts to boil off around 110, and the system is pressurized to say 10 psi, how does that affect the temperature at which it boils? What part of the system monitors and regulates the pressure in the tank?
When this thread first popped up I had a good look around under my truck. The only place that the factory exhaust comes anywhere near the tank already has a dual layer metal heat shield against the tank to block radiant heat. Otherwise the muffler is ~8-10” away on the other side of the driveshaft and due to it’s volume and surface area to cool itself it is much much lower temperature than the cats or downpipes, and therefore not a big source of radiant heat.
The unguarded side of the tank frankly doesn’t get very warm, or at least not much above ambient temp (under the truck), so I don’t think additional heat shielding will do much. This is in stark contrast to an aux tank that gets mounted so close and above the resonator/tail pipe.
One way to measure the impact of radiant heat to the side of the tank may be to measure the temperature difference above and below the fuel level after the vehicle has been running in conditions that don’t cause the fuel to boil. If radiant is a big issue, I’d expect the temp above the fuel level to be significantly higher, because it doesn’t have fuel behind it to cool the thin tank material. Below fuel level, it will take a while of running for the return fuel to raise this temp. And still above should be higher if radiant heat is adding significant BTUs to the system.
If radiant isn’t an issue, the tank material above the fuel level wouldn’t be much higher. Or at least this concept makes sense in my head, even if I’m having trouble explaining it.
I do think Taco is on to something here with fuel returns being a big contributor. A simple in-line cooler could help tremendously if that return temp is high. Right out of the gate though, it seems like good data to collect would be the temp of the return fuel. When I have time I want to look into thermocouple options for this.
No way it’s 10#. We’re talking inches of water column, if that, here.
No off-roading, just driving up 2500 or so feet.
This isn't a 200 issue - it's a Land Cruiser issue, at least since the 80 series. My 80 had the issue, I've read of several 100 and 200 series with the behavior.
Yep