The gas fume problem **SOLVED**(ish)

[TRLBOSS]

I've had the gas fume problem since I've owned the Cruiser - about 6 years now. It seems like it's getting worse, so I figure it's time to dive in and see what I can do to fix it. Last week I took the family camping. There are 6 of us and I pull a small trailer for all of our stuff. It was warmish (80s) and we went over a 10k ft pass here in CO. The combination of all those factors and the fumes and gas tank pressure was horrible. I was ready to start working through the EVAP system, replacing parts, but after reading much on this site especially @2001LC's work and thoughts, I figured I needed to take a more holistic approach.

First step is recording some OBD2 logs driving around today - OAT was probably 80ish. After I got home from the logged drive there was a bit of tank pressure - probably took 3-5 seconds to release after unscrewing the gas cap. This drive wasn't necessarily intended to produce the problem, but more as a starting point to identify how the Cruiser is running. From my limited understanding, I have a fuel trim problem in 3 and 4. I'm hoping @2001LC will take a look at the logs and tell me what you think?

OBD2 Logs (not sure how to post this link without the giant preview)


Helpful thread:

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

Vehicle Info:
2000 Land Cruiser
207k miles
Aftermarket front bumper
Full belly skids
Rock Sliders
Rear bumper

Some maintenance history:
Original radiator
TB/WP service completed 3/30/19 at 197k
new coils and plugs installed 3/2019 at 197k
At some point I sprayed out the radiators - they weren't too bad (may be time to try that again)

What post is complete without a good pic?

 

[flyingscot]

Hi - this may be a bit 'empirical' for your taste - but I have a similar car (age/mileage/duty/Colorado) - I traced my gas tank pressure problem back to the charcoal canister (based on research of this forum & other people's experience) - so I purchased a used one off eBay for $100 - changeout was v. easy & it fixed the problem perfectly. Next time I have the issue I'll buy a new one (think its close to $500) as (in my mind) I have established what the problem is. Appreciate my approach was not very analytical......

 

[excessive]

charcoal canister is either deteriorated or been swamped with fuel due to overfilling or boiling

 

[2001LC]

Hi Noah,

The logs you recorded have hundreds of data points. Most are totally useless, which took me ~40 minutes to delete column by column. Too come up with a few useful columns: ECT F (engine coolant temp in F), MPH, RPM, IAT (intake air temp). Fuel trims (FT) were missing, which would have been nice too have: Long term fuel trims bank 1 and bank 2, also the same for short term FT. Also ATF F (automatic transmission fluid in F), if your reader can capture..

What little I could gather; was your engine is running slightly hot for a 2000LC. You ran ~190 to 194F most times, which is hot for a 80F OAT day. But perhaps you were loaded and pulling a trailer, and have a winch, big lights in front on iron bumper, etc, IDK. Which all service to raise ECT, by blocking air flow, mass retaining of heat and increase drag. I also saw you would idle for long periods of time, more than just stopping at a light. Idling is never a good idea, as damaging to CATs. Idling loads CAT with gunk as they don't get hot enough to burn off gunk. This also will load up o2 sensors w/gunk, and signal to ECM may be slightly off (effect FT). You also don't get the cooling effect of forward motion as air passes radiator and engine.

All "stock" 98-2002 LX/LC with a proper running condenser fan. Should run 184F to 187F all day long in 100F OAT both AC on full blast, on black top in noon sun, stop and go traffic. If we had fuel Trims for your engine. I could than get clue(s) as to if running lean or rich. Which running lean, would raise cylinder head temp and as such ECT in turn. Or if running rich, it would help to keep ECT lower than would be if engine at optimal of 14:1 air/fuel mix. Although 194F is not that bad, and the 03-07 run at that on a 80F OAT day even 197F. It still indicates your running hot for some reason (load on vehicle or coolant issue I can't say).

I suspect you need a good coolant service. Which starts with clean radiators fins (again and again). At 200K mile on clock, it is very difficult to clean the rad fins effectively. Unless fins have been cleaned every 5K miles, since miles one. Think about how many bugs you must clean from windshield and how often. Then consider how much of what hits the windshield like: dust, cotton, grass, bird feathers, etc. just blows away. Wheres bugs and that stuff clogs the radiator fins. How hard is to get bugs off, grill & windshield.. Just raising doesn't get it all, does it!

Also: OEM thermostat install correctly, all air out of coolant system, good working OEM rad cap, proper working reservoir and proper mix of coolant (Toy red 50/50 w/distilled water). Along with; no vacuum leaks and fuel trims near zero (under 5%-+) are key to running in proper ECT range.

Once coolant system and engine is in as good as it can get condition operationally. Than consider things like EVAP stuff like CC canister, it's VSV SW and hoses, and fuel pressure (fuel pressure regulator, fuel filter & pump).

BTW: It is best to not remove gas cap, if fuel boiling. The 98-02 do have a momentary "hiss" as gas cap removed, which is normal. But if venting fumes before gas cap released, just leave it is safest.

 

[flyingscot]

Hi Noah,

The logs you recorded have hundreds of data points. Most are totally useless, which took me ~40 minutes to delete column by column. Too come up with a few useful columns: ECT F (engine coolant temp in F), MPH, RPM, IAT (intake air temp). Fuel trims (FT) were missing, which would have been nice too have: Long term fuel trims bank 1 and bank 2, also the same for short term FT. Also ATF F (automatic transmission fluid in F), if your reader can capture..

What little I could gather; was your engine is running slightly hot for a 2000LC. You ran ~190 to 194F most times, which is hot for a 80F OAT day. But perhaps you were loaded and pulling a trailer, and have a winch, big lights in front on iron bumper, etc, IDK. Which all service to raise ECT, by blocking air flow, mass retaining of heat and increase drag. I also saw you would idle for long periods of time, more than just stopping at a light. Idling is never a good idea, as damaging to CATs. Idling loads CAT with gunk as they don't get hot enough to burn off gunk. This also will load up o2 sensors w/gunk, and signal to ECM may be slightly off (effect FT). You also don't get the cooling effect of forward motion as air passes radiator and engine.

All "stock" 98-2002 LX/LC with a proper running condenser fan. Should run 184F to 187F all day long in 100F OAT both AC on full blast, on black top in noon sun, stop and go traffic. If we had fuel Trims for your engine. I could than get clue(s) as to if running lean or rich. Which running lean, would raise cylinder head temp and as such ECT in turn. Or if running rich, it would help to keep ECT lower than would be if engine at optimal of 14:1 air/fuel mix. Although 194F is not that bad, and the 03-07 run at that on a 80F OAT day even 197F. It still indicates your running hot for some reason (load on vehicle or coolant issue I can't say).

I suspect you need a good coolant service. Which starts with clean radiators fins (again and again). At 200K mile on clock, it is very difficult to clean the rad fins effectively. Unless fins have been cleaned every 5K miles, since miles one. Think about how many bugs you must clean from windshield and how often. Then consider how much of what hits the windshield like: dust, cotton, grass, bird feathers, etc. just blows away. Wheres bugs and that stuff clogs the radiator fins. How hard is to get bugs off, grill & windshield.. Just raising doesn't get it all, does it!

Also: OEM thermostat install correctly, all air out of coolant system, good working OEM rad cap, proper working reservoir and proper mix of coolant (Toy red 50/50 w/distilled water). Along with; no vacuum leaks and fuel trims near zero (under 5%-+) are key to running in proper ECT range.

Once coolant system and engine is in as good as it can get condition operationally. Than consider things like EVAP stuff like CC canister, it's VSV SW and hoses, and fuel pressure (fuel pressure regulator, fuel filter & pump).

BTW: It is best to not remove gas cap, if fuel boiling. The 98-02 do have a momentary "hiss" as gas cap removed, which is normal. But if venting fumes before gas cap released, just leave it is safest.

Can confirm my car has a new radiator & the clutch fan is good. I have witnessed thermostat opening at correct temp (184F) but my car typically runs 190F….. (ref data file). Temp is solid - does not vary ever - so I live with it.

 

[Rgill]

Can confirm my car has a new radiator & the clutch fan is good. I have witnessed thermostat opening at correct temp (184F) but my car typically runs 190F….. (ref data file). Temp is solid - does not vary ever - so I live with it.

At your altitude that seems normal. Air is less dense and pulls less heat off the radiator. I think your good.

 

[TRLBOSS]

Hi Noah,

The logs you recorded have hundreds of data points. Most are totally useless, which took me ~40 minutes to delete column by column. Too come up with a few useful columns: ECT F (engine coolant temp in F), MPH, RPM, IAT (intake air temp). Fuel trims (FT) were missing, which would have been nice too have: Long term fuel trims bank 1 and bank 2, also the same for short term FT. Also ATF F (automatic transmission fluid in F), if your reader can capture..

What little I could gather; was your engine is running slightly hot for a 2000LC. You ran ~190 to 194F most times, which is hot for a 80F OAT day. But perhaps you were loaded and pulling a trailer, and have a winch, big lights in front on iron bumper, etc, IDK. Which all service to raise ECT, by blocking air flow, mass retaining of heat and increase drag. I also saw you would idle for long periods of time, more than just stopping at a light. Idling is never a good idea, as damaging to CATs. Idling loads CAT with gunk as they don't get hot enough to burn off gunk. This also will load up o2 sensors w/gunk, and signal to ECM may be slightly off (effect FT). You also don't get the cooling effect of forward motion as air passes radiator and engine.

All "stock" 98-2002 LX/LC with a proper running condenser fan. Should run 184F to 187F all day long in 100F OAT both AC on full blast, on black top in noon sun, stop and go traffic. If we had fuel Trims for your engine. I could than get clue(s) as to if running lean or rich. Which running lean, would raise cylinder head temp and as such ECT in turn. Or if running rich, it would help to keep ECT lower than would be if engine at optimal of 14:1 air/fuel mix. Although 194F is not that bad, and the 03-07 run at that on a 80F OAT day even 197F. It still indicates your running hot for some reason (load on vehicle or coolant issue I can't say).

I suspect you need a good coolant service. Which starts with clean radiators fins (again and again). At 200K mile on clock, it is very difficult to clean the rad fins effectively. Unless fins have been cleaned every 5K miles, since miles one. Think about how many bugs you must clean from windshield and how often. Then consider how much of what hits the windshield like: dust, cotton, grass, bird feathers, etc. just blows away. Wheres bugs and that stuff clogs the radiator fins. How hard is to get bugs off, grill & windshield.. Just raising doesn't get it all, does it!

Also: OEM thermostat install correctly, all air out of coolant system, good working OEM rad cap, proper working reservoir and proper mix of coolant (Toy red 50/50 w/distilled water). Along with; no vacuum leaks and fuel trims near zero (under 5%-+) are key to running in proper ECT range.

Once coolant system and engine is in as good as it can get condition operationally. Than consider things like EVAP stuff like CC canister, it's VSV SW and hoses, and fuel pressure (fuel pressure regulator, fuel filter & pump).

BTW: It is best to not remove gas cap, if fuel boiling. The 98-02 do have a momentary "hiss" as gas cap removed, which is normal. But if venting fumes before gas cap released, just leave it is safest.

Sorry, I should have cleaned up the logs before sending them over. I'll do that and resend - the fuel trims are in there. I don't think 2000 has access to ATF temp. This trip was unloaded, driving home from the park in the morning (10:45-11:15). Its interesting that you say that about the idling - I don't remember intentionally idling anywhere, I think it's just the nastiness of suburban driving in a bigish city.

I'll look at cleaning the rad again this weekend - as far as the other stuff - I did that as part of the TB service - new thermostat, rad cap, coolant, etc. I can't remember if I did fan clutch, need to check.

I'll be interested to see what you have to say about the fuel trims. Seems like I have vacuum leak or something else I need to run down.

Side note - I'm using DashCommand app and Kiwi 3 OBDII plug in for diagnostics and logging, but am interested if there is something that would work better. Was leaning towards BlueDriver or OBDLink MX+. I like that OBDLink doesn't lock you into an app like BlueDriver.

 

[2001LC]

When I replace radiator:
I flush system first. Which naturally includes opening block drains.
I wash fins of other 2 radiators (AC & AT oil). They also get very clogged, blocking air flow and transfer heat. from/to engine cooling rad.
I also replace thermostat (OEM), and rad cap (which cap come with new OEM rad).
I check to make sure reservoir line has nothing clogging it.
I fill with Toyota coolant (yr correct), and make sure all air out of system, over next few days, by checking under cap.

In all stock 100 series, well tuned with decent compression:
I consistently get: 184F to 187F ECT in the 98-02.
AT temp of 154 to 165F.
This is with OAT from 75f to 100f, both AC on max, from 5,000 to 13,000 ft above sea level. With monetary bumps to 190F in the worst condition in 3PM full sun OAT 100F.

The 03-07 above 65F oat like to run 194f to 197f.

 

[TRLBOSS]

UPDATE

Actions taken:
I power washed out the radiator/condenser/ATF cooler. They didn't look particularly dirty.
I also wired up the auxiliary (a/c) fan so that I can turn it on whenever. Being able to move a bit more air through can't hurt, especially when crawling on a hot day.
I checked for vacuum leaks using propane - didn't detect any
Did a bit more logging - the long term fuel trims seem high for one bank - 10-15% I'm not sure how to further troubleshoot this.

Yesterday I went out into the hot garage and opened the gas cap as there was just a hit of fuel smell in the garage and it vented a bit of pressure for a second. After just sitting in a hot garage!

Next steps:
I think I'm going to get a used charcoal canister off of Ebay, put that in and see if it helps.
Perhaps see about further troubleshooting the EVAP system.

I have camping trips planned the next two weekends, so there will be more driving than troubleshooting/fixing. Perhaps I can get some good logs while crawling.

 

[2001LC]

LT FT above 5% is concerning. The BK1 LTFT 15% indicates some issue with BK 1. If year in signture line I could be of more help, as year matters!

If this data LT FT taken while cruising on flat HWY, steady on gas pedal, MPH & RPM not fluctuating. Then your running lean BK1. Assume good A/F (VVT) & O2 sensors. You either have a vacuum leak, clogged fuel injector(S) or compression issue BK1.

 

[TRLBOSS]

It's a 2000 LC.

 

[TRLBOSS]

Short explanation- moving the return fuel line off the back of the engine solved this for me. Longer explanation to follow.

 

[TRLBOSS]

After much consternation, frustration, anger, and annoyance I've fully solved this problem. A full review of the issue and much speculation can be found here and here. Buried in the first thread is this gold by @J1000 (a steely-eyed missile man, to be sure). I'm convinced this post is THE guide to follow to deal with this problem (and perhaps a new fuel pump for you 06-07 folks). I did all of the fuel line/gas tank/cat shielding and I don't know if it made a difference. And then I moved the return fuel line off of the back of the engine - problem COMPLETELY gone. No pressure, no fumes, no nothing. If you have this problem - start with that return line, it's a 30 minute, one beer, half banana job.
- Fuel Line
- Blingy heat shield
- one small hose clamp needed for the non-engine side

Git 'er done.

 

[Brandon Ryder]

I'm glad this solved it for you. I'm going to try it. Is that the same hose you ordered? For some reason the description doesn't give an overall length, but says it's in 2 ft lengths. I don't believe that. Must be an error. I also generally don't like replacing hard lines with rubber lines, though the shielding would solve some of the problems associated with my experiences with rubber lines. I may try the heat shielding alone over the stock line. Or maybe run my own hard line.

I believe I alleviated some of the over pressure problems by replacing the valve between the charcoal canister and the intake, which allows the engine to burn those fumes, but it still sometimes has residual pressure after shutdown, so i get fumes in my garage after I pull in on a hot day.

My 2001 Tacoma does not have this problem at all, but it doesn't have the valve between the charcoal canister and air intake. It just constantly pulls a vacuum on the charcoal canister. I belive i tried bypassing the valve on the LC but it didn't run right.

 

[TRLBOSS]

Yes, it’s what I ordered - It’s 25 ft of hose (300” can be seen in the details). Way more than needed, but saved me a trip to the store.

 

[2001LC]

It would be very interesting to see three or more 100 series, of different years 98-02, 03-05 & 06-07 (the 3 different CC and fuel tank combo).
That have fuel boiling issues, corrected by re-route and insulating the fuel return line.

To be a valid test, without anything else being done!
Nothing else done: No coolant services, Tune, Charcoal Canister (CC), Heat-shielding, etc..

 

[TRLBOSS]

It would be very interesting to see three or more 100 series, of different years 98-02, 03-05 & 06-07 (the 3 different CC and fuel tank combo).
That have fuel boiling issues, corrected by re-route and insulating the fuel return line.

To be a valid test, without anything else being done!
Nothing else done: No coolant services, Tune, Charcoal Canister (CC), Heat-shielding, etc..

Yes! I live in the Colorado Springs area and would be willing to help anyone who needs it get this done - I have plenty of hose left.

And to be fair - I thought both you and @J1000 were right on this problem. His main point - "we have a heat problem" and your main point "if the vehicle were within spec we wouldn't have a (heat?) problem". I think on this issue, though, there seems to be a fairly narrow band of 'within spec' and that's why it is such a wide spread issue and Toyota could/should have engineered something better. My Cruiser runs great, but has been modified beyond stock so I'm not troubled by having to 'modify' it yet again to avoid this issue.

 

[TRLBOSS]

I also generally don't like replacing hard lines with rubber lines,

To be fair - it's like 1/4 hard line, 3/4 soft:

 

[suprarx7nut]

Yes! I live in the Colorado Springs area and would be willing to help anyone who needs it get this done - I have plenty of hose left.

And to be fair - I thought both you and @J1000 were right on this problem. His main point - "we have a heat problem" and your main point "if the vehicle were within spec we wouldn't have a (heat?) problem". I think on this issue, though, there seems to be a fairly narrow band of 'within spec' and that's why it is such a wide spread issue and Toyota could/should have engineered something better. My Cruiser runs great, but has been modified beyond stock so I'm not troubled by having to 'modify' it yet again to avoid this issue.

If you want to come up to ADGU I'd gladly be a tester for the 06-07. We're up in Frederick. Hoping to do a couple high altitude day trips at least this year. I've never been stranded by this problem, but definitely have the pressurized gas problem after long highway trips at altitude. Car is totally stock in regards to this.

If you're in the market for a drawer system maybe we can work out a handsome discount if you do the install, haha. I'm so negative on time lately, my calendar is just a big flashing "NO" banner. Happy to help the research cause if all you need is a Cruiser doing high altitude trips.

 

[TRLBOSS]

If you want to come up to ADGU I'd gladly be a tester for the 06-07. We're up in Frederick.

Geez, that is something (travel around meeting the cruiser crowd) I would love to do, some day. But unfortunately, I feel the same way about my schedule - not much buffer there - so I can only offer 'you come to me' help at this time.