Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen? (3 Viewers)
- Thread starter 2001LC
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guardcompany
Shea
Fingers crossed on calling this issue solved for me. I towed in the heat last desert trip and zero issues still. Hopefully this will be my second summer of no issues after going down the rabbit hole on this issue.
@guardcompany, that’s good news! Glad to hear it. Do you think there was any one specific change that mattered most? Guessing the new radiator probably played a big part.
Just to finish off my heat shield/exhaust saga, the Borla muffler is significantly smaller than stock. There is a lot more room between the muffler and the gas tank now. I’m not sure how much that source of heat contributes to the problem, but it’s gotta help a little, I think.
Just to finish off my heat shield/exhaust saga, the Borla muffler is significantly smaller than stock. There is a lot more room between the muffler and the gas tank now. I’m not sure how much that source of heat contributes to the problem, but it’s gotta help a little, I think.
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guardcompany
Shea
I think the fan clutch helped the most. But it's a mixture of things. If your cooling system is 100% maintained/refreshed and you can keep the gas temperature down its a winning combo.
I did my fan clutch, DIY heat shield, wrapped fuel lines and fuel pump all at the same time and it fixed it. Which single was one it? I don't know. But I had already done the radiator, o2 sensors and aftermarket smaller muffler before that and I noticed the problem was better but not completely fixed.
Bottom line was my cooling system wasn't working 100%. I was tracking my engine temp and the engine was getting too hot on those hot slow summer trails then add in Toyota's design of running fuel lines next to the cats and you have a failure point and the EVAP system can't keep up.
My EVAP system still is working and wasn't too abused by this issue. I do have a box of $600 worth of VSVs, hoses and CC in my garage I bought but after the issue was fixed I lost motivation to do. I need to get on that soon.
That's great! Really good info. Thanks for recaping it.
I suspect my cooling system isn't as cool as it could be. I've always done the factory maintenance, but it might be time for a new radiator and fan clutch.
I'm curious about the fuel pump. How does that help with the temperatures? Does it make the engine run lean as it ages and therefore hotter?
guardcompany
Shea
The theory is as the pump ages it becomes less efficient and works harder. I did it half as a general preventative maintenance and half to see if it was related to this issue. I'm sure someone here can chime that has a lot more knowledge on that.
Eyedaho
SILVER Star
I have no idea if it helps with the over heating, but for the low price of a new Denso pump it was cheap insurance that it's less likely to fail on me. I still have a cheap-o in the spares box in case, but I'd rather not have to change it out in the dark. In the snow. Uphill both ways.
Eh... I had the boiling issue a few months after installing a new fuel pump in my 99.
guys, I have tried a few of these things, non-ethanol gas was the trick........
That does seem like the easy ticket. However, I live on the arrow in the map below. It's not a realistic option for me.
Yep. Non ethanol gas worked even after I put in a new radiator, fuel pump, fuel filter, gas cap, evap canister, and checked for leaks.
Here’s a video I made, just in case anyone needed some assistance on wrapping their fuel lines near the cat. I’m going to replace my fan clutch and radiator soon.
guardcompany
Shea
I wish that was my trick, I saw a little less boiling with non-ethanol but it still happened. I remember getting gas in Lake City and doing Alpine Loop back and still smelling fuel, I was bummed. Last year I ran all the trails in the area in hotter weather with California sh*tty ethanol gas with zero issues.
Has anyone seen a 100 series charcoal canister fail and allow the charcoal to clog up the evap lines? I've seen other vehicle owners fight this problem on cars after the evap lines become clogged with charcoal from a failed canister. They replace the canister, the purge valve, gas cap, all of the known culprits without finding the lines are clogged with charcoal.
A few years ago I would spot a nice-looking car at the junk year and try to guess the reason for it being scrapped. Seven out of 10 times I could see where a clogged evap system sent the car to an early grave.
A few years ago I would spot a nice-looking car at the junk year and try to guess the reason for it being scrapped. Seven out of 10 times I could see where a clogged evap system sent the car to an early grave.
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Yep. So many variables who really knows what the trick is…
What's your fuel temperature?
Rephrase => I replaced all those things and was still getting vapor lock. Now when it gets super hot in Vegas or I head to Colorado to altitude I have been using non-ethanol gas…since I have been doing non-E gas I’ve that last three years never had vapor lock. To answer your question though I don’t have the capability to measure my fuel temp.
My buddy and I went to UT this past March and even tho we were at higher altitudes I thought the ethanol has would have been ok. But I was towing headed up the Western Slope and that was it. Around Eagle CO I rolled in to a gas station and we stalled. Waited 15 minutes and started right back up.
Only happens out West. 4,000' or better, and above 70 degrees.
Only happens out West. 4,000' or better, and above 70 degrees.
- Thread starter
- #579
The 06-07 fuel pump, which Toyota change to a smaller one in the USA 06 4.7L VVT, is weak. We can check fuel pressure by the book, but doesn't reveal the issue.
What I've found is tell tell signs. Basically fuel pump and wires get hot. Heat increases electrical resistance, reducing current/AMPs to and in fuel pump. This slows pump and reduce fuel pressure to much, in the low speed of these variable speed fuel pumps. If we check for DTC as engine dies/stalls. We'll often see pending lean code(s). Codes are typical for both banks and don't become confirmed codes.
Here's the sign:
Engine runs in higher RPMs, like when pull up a hill. Higher engine RPM signals fuel pump to run at higher speed. Fuel pump runs hotter at higher speed. So the longer time frame we run at higher RPM, the hotter wires to pump and fuel pump become. So ascending a hill, especially a long hill. Is when we see happen most often. Then as we let of the gas pedal (crest the hill and begin descending). RPM drops and so does fuel pump speed. At this point fuel delivery pressure/volume is not enough, as pump slows to much. This almost always is only when outside air temp is hot, especial on a sunny day increase ground heat.
So hills and mountains passes are where accrues the most. But as pump gets weaker with time. Even just short acceleration, than let off gas pedal it may accrue.
Typically one only needs to just let sit an cool a few minutes and it starts. This is often refer too as vapor lock. It is not. It's fuel pressure dropping to low, resulting in fuel starvation.
This seem more prevalent at higher altitudes. IMHO two reasons for this.
1) We've more long hill or mountains pass we ascend.
2) Less oxygen at high altitude. ECM slow fuel injectors (reduces fuel to cylinders) to compensate.
Happens at low altitude also. But seems to take higher OAT days.
Since this is issue dealing with resistance issues. Battery, it's posts, clamps and ground points. Need kept in tip top shape. Or, over time, the weak current from battery is hard on all motors in the vehicle. i.e fuel pump, brake booster motor, AHC pump, HVAC blower motor.
What I've found is tell tell signs. Basically fuel pump and wires get hot. Heat increases electrical resistance, reducing current/AMPs to and in fuel pump. This slows pump and reduce fuel pressure to much, in the low speed of these variable speed fuel pumps. If we check for DTC as engine dies/stalls. We'll often see pending lean code(s). Codes are typical for both banks and don't become confirmed codes.
Here's the sign:
Engine runs in higher RPMs, like when pull up a hill. Higher engine RPM signals fuel pump to run at higher speed. Fuel pump runs hotter at higher speed. So the longer time frame we run at higher RPM, the hotter wires to pump and fuel pump become. So ascending a hill, especially a long hill. Is when we see happen most often. Then as we let of the gas pedal (crest the hill and begin descending). RPM drops and so does fuel pump speed. At this point fuel delivery pressure/volume is not enough, as pump slows to much. This almost always is only when outside air temp is hot, especial on a sunny day increase ground heat.
So hills and mountains passes are where accrues the most. But as pump gets weaker with time. Even just short acceleration, than let off gas pedal it may accrue.
Typically one only needs to just let sit an cool a few minutes and it starts. This is often refer too as vapor lock. It is not. It's fuel pressure dropping to low, resulting in fuel starvation.
This seem more prevalent at higher altitudes. IMHO two reasons for this.
1) We've more long hill or mountains pass we ascend.
2) Less oxygen at high altitude. ECM slow fuel injectors (reduces fuel to cylinders) to compensate.
Happens at low altitude also. But seems to take higher OAT days.
Since this is issue dealing with resistance issues. Battery, it's posts, clamps and ground points. Need kept in tip top shape. Or, over time, the weak current from battery is hard on all motors in the vehicle. i.e fuel pump, brake booster motor, AHC pump, HVAC blower motor.
- Thread starter
- #580
