New cap, still no gas tank pressure? - Toyota Nation Forum : Toyota Car and Truck Forums

1sthumper · 04-06-2005, 12:03 PM

Thanks in advance for helping the newbie. My 01 Corrola is more technologically advanced than my 84 Civic! My check engine light is on. I replaced the gas cap cause I wasn't getting any pressure in the tank. I'm still not getting any pressure in the tank with the new cap. What's the next logical step?

Thanks again!

Flashmn · 04-06-2005, 12:36 PM

Pressure in the tank?
No no, you dont get pressure in the tank, the pump SUCKS fuel out of there.

1sthumper · 04-06-2005, 12:46 PM

Quote:

Originally Posted by Flashmn

Pressure in the tank?
No no, you dont get pressure in the tank, the pump SUCKS fuel out of there.

I was told that the woooshing noise your gas tank makes when you remove the gas cap was important to the whole emissions deal? And that's why my check engine light was on because the tank wasn't building any pressure, so I replaced the cap. I still don't get a woooshing noise when I remove the cap?

foodaa · 04-06-2005, 06:27 PM

You got it. Your gas cap must be able to hold pressure for emissions. Use your old gas cap.

Flashmn · 04-06-2005, 11:51 PM

That would be vacuum most likely.

karugs · 04-07-2005, 04:47 PM

Foodaa is right, if your old gas cap makes that wooshing sound it's normal since the fuel tank creates vacuum as fuel is used up. When you open the gas cap it sucks in air due to vacuum, not blows out air due to pressure.

So if the old gas cap made that sound, return the new one and use your old.

karazy · 04-07-2005, 08:05 PM

If the new cap is OEM, the next step would be to check for obvious leaks or get the system pressure checked. There is probably a leak elsewhere.

rated_w · 04-08-2005, 02:50 PM

tighten the gas cap till you hear 5 clicks. then reset your ECU .. if the CEL still turns on you either have a leak somewhere or a bad cap

1sthumper · 04-08-2005, 04:15 PM

Thanks all. I just assumed it was pressure similare to removing the cap off of a portable gas can. The vacuum makes sense, of which I get none, with the old or new cap. I'm going to reset the pesky cel this week end and see how it goes. Thanks again.

81SR5 · 04-08-2005, 10:36 PM

Why is your light on? Did you have it scanned? If not, how do you know it has anything to do with the evap system?