Gas Smell Gremlins Sigh. Cant Pin It Down.

[BoaR]

Bon, where to start... (and yes i searched lol)

Suddenly started smelling gas in the cabin about a week ago. figured it was because i topped it up to full. then i realised that iver done that many many times before, and never did it smell once.

The gremlin in this is it stops and starts again for no explicable reason. I love intermittant problems

this week ive been trying to pin down "exactly" how i can reproduce the smell 100% every time all the time.

-> sitting parked for a day: gas smell on entering car.

-> driving with recirc button ON, and the AC off: no smell.

-> driving with recirc OFF, ac off: no smell

-> driving with AC on (recirc): no smell

-> driving with AC on (recirc off): no smell

-> 100% reproduction of gas smell, regardless of recirc on/off if car is driven around 90-100Km (62mph derp). seems that when you push the car to those speeds it takes a few seconds and you smell gas right away in the cabin. only exception is when AC is on, 0 smell at all.

car is a '98 es300 btw. , and when I ran the diag. it throws no codes at all. People in the other thread were mentioning the Evap system, haynes manual said pretty much the same thing. but reading more into it, any fault will throw an evap code.. and i triple checked to make sure. no codes at all. car is clean as a whistle in the readings.

So i took it to a friends driveway today, and we pretty much fine tooth comb'd the engine bay following every hose, connector you name it to/from the evap schematics. we found no cracks, tears, holes, leaks nothing.. the entire system seems to be in excellent shape. tugging on the hoses didnt move them the slightest, and seeing as the engine bay is a bit dusty, any wet leaks would be instantly noticable, but feeling every hose from start to finish confirmed that its all looking good.

the gas cap O-ring is in great shape, and when !Removed!/unscrewing you hear a full pressure release of a bit less than a second.. so system is holding a decent, if not excellent ammount of pressure.

smelling the gas cap area when screwed using 2-3 clicks has no odour at all. smelling the engine bay has no gas smell at all either (which is what stumps me, because if the evap system is not working right and the push fan fumes venting cant get the smell out, it would go right into the cabin but you would instantly smell the gas once you pop the hood, which isnt the case) . the only area that smells "slightly" and very very faintly, is driver side rear wheel when placing your head under the trunk area directly back from the wheel itself.

Literally the only thing I have not tried was ripping apart the evap housing to take a look at the charcoal filter. as the friggin placement if the sucker is underneath the master brake cylinder and the air filter housing. I dont really wanna muck about with that not even knowing for certain it's the canister... googling up some threads doesnt seem to give a lot of info on them going "bad" or needing replacing type thing.

So sorry for the long info post... if someone has some clues as to this friggin annoying problem, please by all means throw some light on the subject.

Much appreciated!

[LEXIRX330]

Have you tried looking under the car? You need to look under the car too. I had a 1997 jeep Cherokee that had a smaller thing if I filled it more than 3/4 of a tank when I cut it off I heard this gulp...gulp...gulp sound and all I could smell was gas fumes. If it was under half a tank no smell no sounds. Turns out there was a small hole in the top of the fuel tank and the fuel pump was bad too which was causing the noise.

Good Luck!

[BoaR]

Hmm, thanks for the info.

Guess i'll be jacking the car up and taking a look underneath!

If anyone else has clues, by all means chime in! :)

[lexis lexus]

Hmm, thanks for the info.

Guess i'll be jacking the car up and taking a look underneath!

If anyone else has clues, by all means chime in! :)

I'm thinking that fumes are venting from something near the firewall and getting sucked into the cabin via the air intakes. Open the hood and it all goes up and away quickly. Of course, this doesn't explain why you smell it when car has been sitting -- is this before or after you start it up?

LL

[BoaR]

overnight, sitting for a day without being started, or after parking at the mall while shopping. doesnt matter, the problem arises. and other days i cant smell any fumes at all.

I took a look at the O-seals around the firewall and they seem to be in order also.

When i get some time i guess ill jack the car and verify the tank area. cant figure out why it would smell gas every time if im driving at 100, if it was some crack or hole in the tank. that isnt exactly where the fumes would be venting off. (though that would explain the sitting). yet the firewall like you mentioned would explain the driving speed issue. sigh

I hate gremlins !

[lexis lexus]

overnight, sitting for a day without being started, or after parking at the mall while shopping. doesnt matter, the problem arises. and other days i cant smell any fumes at all.

I took a look at the O-seals around the firewall and they seem to be in order also.

When i get some time i guess ill jack the car and verify the tank area. cant figure out why it would smell gas every time if im driving at 100, if it was some crack or hole in the tank. that isnt exactly where the fumes would be venting off. (though that would explain the sitting). yet the firewall like you mentioned would explain the driving speed issue. sigh

I hate gremlins !

I've never had this kind of experience, but I'm naturally analytic and just thinking about it is of interest. What would cause ....?

So, after reading more today, I thought about the probability that the fuel system is generally under pressure, even when car is off. That's why you usually need to disconnect fuel system/relays and run a car dry before going to work on fuel lines. This leads me to think about what would happen if you had a slow pinhole sized leak, that might become manifest after a few hours to a day, then when the system is turned on again and fuel begins to move and be shunted into the intake, the fumes go in the proper direction.

LL

[cfrazierjr]

I have been experiencing the exact same problem and have no idea what is going on. We took the car to 2 mechanics but when we get there, the smell is gone. Unfortunately, looks like we will be heading to the dealer in the morning. I really hate that because I feel they may try to rip me off. Any ideas please????

[flanso]

I had an intermittent fuel smell in my 2001 ES300. I found it to be the fuel pressure damper that is mounted on the on the driver's side of the fuel rail. Apparently, it dampens pulsations and excess pressure in the fuel rail. Mine leaked only occasionally when high pressure caused the thing to actuate. I discovered the leak by driving until the car was up to operating temperature and then parking with the car idling and observing the fuel rail. It took several repeats of the process before it leaked. The damper is round, about an inch and a half in diameter and covered by a milky colored snap on plastic cap. Sorry, I misplaced the part number but, as I recall, the thing cost about 60 bucks.

[LoveLearn]

I've experienced a Lexus V-6 that developed leaky injector gaskets. The fuel pump would deliver over 50 psi but the pressure regulator dumps excess pressure through the fuel return line back into the fuel tank. So those injector seals see about 50 psi fuel pressure which the injector electrically-triggered valves open and close as directed by your engine control computer. When those injector seals are new, they are very elastic. But through age and run time with some vibration, they can develop seepage. People with especially sensitive gasoline smell capabilities know when these begin leaking long before ordinary passengers smell anything.

Changing the front 3 injectors is easily accessible. But changing the rear 3 is much more difficult. The Allen-head retainer bolts which must be removed to access the rear three injectors take an 8mm Allen tool. DO NOT use the almost identically-sized SAE-sized Allen driver tool. It feels like a sufficiently tight fit, but it can round out the drive hole in those 8mm Allen head cap screws.

Using an odor-free sniffer hose will enable you to detect your fuel leakage source.

Good luck,

John

[msamo]

I have the same problem with my LS400. I have an intermittent fuel smell in the cabin for no particular reason. The smell is the strongest inside the trunk. Sometimes It only smells there. I have checked the fuel system up and down, took it to a Lexus dealership mechanic, and neither of us could figure it out. I also thought it might be the charcoal canister, but am not yet willing to go replacing it without some more insight on the issue. If anyone has had any luck getting rid of this problem please post.

[DJ Rain Candy]

I was going to post the same thing. It happens with my 02 ES as well. Charcoal would make sense since it only does it at highway speed at 3k-4k RPM whenever I increase fuel delivery it smells of gasoline and or burnt plastics (or probably charcoal gasoline) perhaps the design on these two isn't far from similar?