vaughn37

what is wrong with the slant cap that you can get at advance auto i got one on my car

deanshark

The new gasket has the groove in it to let the pressure out. When you tighten the cap over and over you're crushing the gasket, it is only a piece of rubber. With the gasket crushed you have too much pressure which effects the throttle. I paid less then $10 for mine, from the dealer, but that was about a year ago. But hey, if you don't want to change it, then don't. But now you'll be thinking, "would that have helped with my problem?"

Fred J

I suppose that makes sense. Maybe it's a one way vent so air gets in but not out.

Well, I'm going to replace it only because I think it might help with fuel economy, because even after I experienced the symptoms, and tried unscrewing the cap when it happened, they persisted. So it isn't that.

I appreciate everyone's input. This is just so frustrating. So many potential solutions and not one is certain to fix it.

Fred J

Fred J

Hey Vaughn37, I figured it would be cheaper to just buy the gasket than to replace the whole cap, but knowing Lexus, it probably costs more for just the gasket if I get it from them. Maybe I'll just go to Advance and get it over with. Though the original cap looks nicer and of better quality. Maybe I can just remove the gasket from the Stant!

Fred J

Fred J

So I called Lexus today to see whether they sold the gasket separately. I had looked for a Stant cap at Amazon, and only one review was available, which said that it failed pretty quickly and the guy's engine light came on, and then he had to replace it with a genuine Lexus part. Well Lexus doesn't just sell the gasket, according to my parts person, but they'll sell the gas cap for $34. In my book, that is ROBBERY.

Well, the guy at Lexus told me the cap is supposed to create a vacuum, and that whoosh is supposed to be there when you unscrew it. Which is just the opposite of what the link said from the earlier post. The guy said even brand new Lexuses will do this and that's what they're supposed to do.

So that article that said there shouldn't be a vacuum was completely wrong, or else Lexus is. Either way, I am getting 100% conflicting info. And since my cap is doing what Lexus says it should, I'll save my money and keep the cap and gasket.

Fred J

deanshark

The gasket is sold seperately. As steve2006 said "the part # is 77316-16010" but it's actually $15.06.
https://secure.sewellparts.com/shopping_cart
And also actually, it's part of your 60,000 mile maintenance schedule.
http://www.edmunds.com/car-maintenan...&mileage=60000
Yes it's supposed to create a vacuum but it's also supposed to let out the extra pressure. (the purpose of the groove) The woosh is supposed to be there a tiny bit but you said "I get a very powerful rush of air". That's not supposed to be like that. Before I changed my cap gasket the car was running like CRAP. It's running a hell of alot better since. When I used to remove the cap, if I turned it 1/8 of a turn I had the woooosh and hissss for a good 5 seconds. You telling me all those fumes releasing is normal? I didn't like having that big of a fire hazzard with my car every time I was at a gas station. With all the Billions of dollars and how many ever years it took to create this masterpiece, I highly doubt that the Lexus technitions designed it to be a fire hazzard.
Anyway, I never said the gasket was your problem with the car dieing out, it was a suggestion b/c it worked on my car and many, many other members cars. Even if it's not your main problem, it's a common repair. And it's cheap. If I could spend $15 to see if that fixes it, why not? So, change it, don't change it, take my advice, don't take my advice, whatever. Good luck with it.

sam12345

iTrader: (1)

I thought the excess pressure was released through the charcoal canister to prevent pollution. I think that the gas cap is to prevent vacuum not pressure it must work like a one way valve to let air in not out. So if you remove your cap and have a vacuum (air rushing in) then I would think it's the cap. If you have "excessive" pressure than it's the charcoal canister. If you have a vacuum then I can see a fuel starvation problem but I doubt pressure would do that. My guess is that as somebody stated the fuel tank has sediment and that the fuel pump strainer is partially clogged (the bottom part) and when the fuel is low it struggles to pump but when the fuel is high it can go through the clean (higher part of the filter) I am envisioning the GM filter float fuel pump combo inside the tank Nd I'm not familiar with how Lexus did it so if they do it different I could be completely wrong. One thing I dont get is your statement that the mechanics can't diagnose it because when they have it the issue does not occur yet you ay that when tank is near empty it always occurs. Well take it to the mechanic with the fuel tank near empty. Another thing it could be is a fAulty fuel level reading and you are running out of gas because it's almost empty.

sam12345

iTrader: (1)

I could be wrong about the gas cap only letting in air and not letting fumes out since the car in question is pre obd2

sam12345

iTrader: (1)

Some more info

If a blockage occurs in the liquid-vapor separator or in the vent line between it and the EVAP canister, the fuel tank will not be able to breathe properly. Symptoms include fuel starvation or a collapsed fuel tank on vehicles with solid-type gas caps. If you notice a whoosh of pressure in or out of the tank when the gas gap is removed, suspect poor venting. You can check tank venting by removing the gas cap and then disconnecting the gas tank vent line from the EVAP canister. If the system is free and clear, you should be able to blow through the vent line into the fuel tank. Blowing with compressed air can sometimes free a blockage. If not, you will have to inspect the vent line and possibly remove the fuel tank to diagnose the problem.

http://www.aa1car.com/library/evap_system.htm

sam12345

iTrader: (1)

Here is a link to an image of a fuel pump asm for 92 ls400 you see the filter? I bet yours is partially clogged

http://www.alltoyotalexusparts.com/13891.shtml

Fred J

deanshark -

The gasket you referenced above does not seem to fit a '92. It only goes back to '95 on the Sewell site. Any suggestions?

Fred J

deanshark

I don't know why it didn't show up, it was all there when I posted it. I'll get it up for you again soon.

If you go buy the part #, yes it only goes back to 95, I don't know why. Sometimes ya have to do some leg work. (Like the old days)
OK here ya go. If this doesn't show up then go to Sewell site for your year and model, go to the "body" section and click on the "fuel tank & tube"
http://lexus.sewellparts.com/oem-cat...S400-1992.html

toyrolla86

My car did this too

I just screwed the cap a lil bit and since then no more stalling it my car would die when I turned off the ac and my cap blew off into my hand since then I just leave t a lil bit loose and I'm stall free