Gasoline fumes while driving and after driving - 2025 4Runner TRD Pro

[JohnnyMTB]

Not sure if this could be related but In Nov this year with 1500 or so miles on the truck I heard this whirring sound coming from the drivers side near the rear wheel. Loud enough to hear 15 or more feet away.
Sounded like a miniature air compressor.
All ignition etc off. Not sure how long it had been whirring before I noticed it.
Before climbing under it in 4 inches of slush I called a dealer.
They told me it was normal and part of a self test those things go through. As I recall I believe he told me it was part of a self test of the EVAP system.
They also mentioned that was why the gen 6 batteries were going flat.....
I cannot recall a bunch of battery problems here so that may be chat.

I would keep it outside especially with this small motor randomly starting a test.

Thanks for the insight. I haven't heard any motors whirring so not sure if our problems are the same.

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[bakutheleo]

@Lamuncha That sounds to me like hogwash. I would not think anything would be running as a "test" when the engine is off. Maybe the electronics checking for software updates, but does not use significant power and obviously you would not hear it. Doesn't make sense to me that anything mechanical would run--if nothing else so it would not run the battery down. I have never heard such a noise. The only thing I have heard that is similar is when I open the driver door--I expect that is something "getting ready" for me to get in and start the vehicle, as it only happens with the driver door. I have no idea what it is doing or why it does it at that point though.

 

[Lamuncha]

Bothered the heck out of me as well. Not something I would design into anything let alone an automobile.
But there it was whizzing away, either a compressor or vacuum pump.
It had been parked for a few hours in the driveway.
When I left the house it was apparent something was running out there. As best as I could determine the sound was emanating from the top of the axle area by the wheel. Basically below the fuel fill.
The service guy seemed to immediately know what I was referring to.
I remember thinking glad it wasn't in the garage.
Got to make an effort to squirm under it and find this thing.

 

[Lamuncha]

I think this is the culprit. Might be over the spare. Not sure how long the test should run but there are reports of them getting stuck on for hours.

 

[Boyds4Runner]

I have a 2015 4Runner (5th gen). Been looking at the 6th gen for some time as I prep the 5th gen for my youngest daughter to inherit.

Two thoughts

1) This may not solve the problem here but give some insight to the EVAP test. I have camped/slept in the 5th gen and the car is also kept in the garage when home. Right around the 5 hour mark of the vehicle having been shut off, an air-pump sounding noise does come out from above the rear-axle driver side. It is, as others have said here the EVAP test that the car runs. When I have camped/slept in the car it would run for around 7-10 minutes before shutting off. No fuel smells observed from that.

2) 4Runners used to have a little access panel to the fuel pump under the driver side second row seats. From there one could see the fuel pump where it goes in to the fuel tank. This panel would allow access to unplug the electrical connectors and prevent ripping the wires apart when dropping the tank to service/replace the pump. If the 6th gen still has that, it might be a good place to check for the fuel smell there. Perhaps a seal is not properly set in that area in terms of the fuel smell noticed in the garage? Also that panel area would be a good place for fuel smells to get in to the cabin.

I do see that the fuel tank on the 6th gen is now on the passenger side so try under the second row passenger side.

Keep us posted in any case. I am a curious, future purchaser of a 6th gen here. Wanting to learn more than the owners manual provides via the real world posts in these forums.

 

[Lamuncha]

Not knowing what effect this test actually has on components, what would happen if it ran excessively? My guess is no alarm. No code because it did not fail. Which is why no codes popped up at the dealer.
Could it cause fuel vapors?

 

[JohnnyMTB]

I have a 2015 4Runner (5th gen). Been looking at the 6th gen for some time as I prep the 5th gen for my youngest daughter to inherit.

Two thoughts

1) This may not solve the problem here but give some insight to the EVAP test. I have camped/slept in the 5th gen and the car is also kept in the garage when home. Right around the 5 hour mark of the vehicle having been shut off, an air-pump sounding noise does come out from above the rear-axle driver side. It is, as others have said here the EVAP test that the car runs. When I have camped/slept in the car it would run for around 7-10 minutes before shutting off. No fuel smells observed from that.

2) 4Runners used to have a little access panel to the fuel pump under the driver side second row seats. From there one could see the fuel pump where it goes in to the fuel tank. This panel would allow access to unplug the electrical connectors and prevent ripping the wires apart when dropping the tank to service/replace the pump. If the 6th gen still has that, it might be a good place to check for the fuel smell there. Perhaps a seal is not properly set in that area in terms of the fuel smell noticed in the garage? Also that panel area would be a good place for fuel smells to get in to the cabin.

I do see that the fuel tank on the 6th gen is now on the passenger side so try under the second row passenger side.

Keep us posted in any case. I am a curious, future purchaser of a 6th gen here. Wanting to learn more than the owners manual provides via the real world posts in these forums.

Thank you for the troubleshooting ideas and comparison to old and new 4Runners!

 

[CuttingedgeSport]

I have also heard this random evap test/whirring sound occur on our 2025 4Runner after being parked and shut off for a long time.

No other issues or fuel smell for me though.

 

[6thGen1419]

Test the closed garage:

1. Portable combustible gas detector (best method)

• Often called an LEL detector or VOC/gas sniffer
• Used by mechanics, firefighters, and HVAC techs
• Detects gasoline vapors (and other flammables) in ppm or % of LEL
• Battery powered and spark-safe

This is the correct way if you want certainty.

 

[kekecarioca]

It's extremely hard to tell where the smell is coming from. After an hour sitting in the garage the entire garage fills up with fumes. If I take the vehicle outside and lift the hood you can't really figure out where the smell is coming from. Additionally I start did smelling it in the cab while driving probably about 2 months ago and it continues to get worse. The dealership said they did an EVAP pressure test and it came back with no issues. I'm out of total loss

Chasing tails sucks... and definitely not normal what is happening to you.
Lots of comments here, but maybe as someone said : high pressure fuel rail?
EVAP seems to be out of the question. maybe?

The Hybrid 4runners have a collection of "chirps" & "whirls" going on.
- electric parking brake.
- Hydraulic brake pressure pump (when you fist open driver door )
- the EVAP "thing" when it sits parked for a while ( mine is a loud Chirp a second long.)

Do you have another dealer option you can call and hopefully get better service?
This "bye bye" we can't figure it out answer is BS for your time wasted already.

Good luck and keep us posted.

 

[6thGen1419]

Chasing tails sucks... and definitely not normal what is happening to you.
Lots of comments here, but maybe as someone said : high pressure fuel rail?
EVAP seems to be out of the question. maybe?

The Hybrid 4runners have a collection of "chirps" & "whirls" going on.
- electric parking brake.
- Hydraulic brake pressure pump (when you fist open driver door )
- the EVAP "thing" when it sits parked for a while ( mine is a loud Chirp a second long.)

Do you have another dealer option you can call and hopefully get better service?
This "bye bye" we can't figure it out answer is BS for your time wasted already.

Good luck and keep us posted.

Why not test in order to get a handle on the nature of the problem?

1. Portable combustible gas detector (best method)

• Often called an LEL detector or VOC/gas sniffer
• Used by mechanics, firefighters, and HVAC techs
• Detects gasoline vapors (and other flammables) in ppm or % of LEL
• Battery powered and spark-safe

This is the correct way if you want certainty.

 

[127.0.0.1]

Why not test in order to get a handle on the nature of the problem?

1. Portable combustible gas detector (best method)

• Often called an LEL detector or VOC/gas sniffer
• Used by mechanics, firefighters, and HVAC techs
• Detects gasoline vapors (and other flammables) in ppm or % of LEL
• Battery powered and spark-safe

This is the correct way if you want certainty.

this might work too, or UV dye

 

[FlaFlaFloFly]

I have had this same issue since I’ve owned the truck (10k miles). I’ve never mentioned it to the dealer because it is so sporadic I don’t think they’d ever be able to replicate it. I changed the air filter and cabin air filter and it seemed to help for a little bit, but it’s back. The air filter wreaked of gas when I took it out, which I had never noticed before on any car I’ve ever owned.
I never mentioned it on the forum for fear of being blasted.

 

[Minnesota4Runner]

The sound is real. I caught it the other night and went into full alarm mode. I started and stopped the engine to make it stop then looked it up online. Evap system test. I dont like that kind of load on my idle battery. No gas smell yet.

 

[6thGen1419]

I have had this same issue since I’ve owned the truck (10k miles). I’ve never mentioned it to the dealer because it is so sporadic I don’t think they’d ever be able to replicate it. I changed the air filter and cabin air filter and it seemed to help for a little bit, but it’s back. The air filter wreaked of gas when I took it out, which I had never noticed before on any car I’ve ever owned.
I never mentioned it on the forum for fear of being blasted.

You can't ask your dealer to smell your air filter?

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