Help with 01 Honda Civic Hissing noise?

Question

I have a hissing noise coming from the rear of my car. I have narrowed it down to something that has to do with the fuel tank. It only hisses when the car is on and I only notice performance issues with the car when the fuel tank is less than half full. When the tank is less than half full, you cannot step on the gas peddle to fast or the car acts like it is going to stall. My check engine light did come on a few days ago. I went and had it looked at but the code for the car said it was the gas cap. I want to know if anyone knows what it might be and how much it might cost to fix.

Answer 1

the fuel cap on that car is supposed to let air into the gas tank as the fuel level drops to keep the pressure in the tank positive. If the tank is not venting then their will be a vacuum in the tank that can pull air around the seals of the fuel cap or around the on-board vapor recovery valve. the lack of vent for the tank could cause you to feel like you're running out of gas when the vacuum becomes greater such as when the fuel level is below 1/2 tank.

the check engine light is for the fuel cap indicates a leak in the tank sealing system. that could be a true leak or it could be caused by the vacumm in the tank pulling air around the seals.

I would recommend you start by replacing the gas cap. you could try this when you hear the noise park the car, leave the engine running and open the gas cap very slowly. you will hear a rush of air going into the tank. if the noise goes away then the chances are the gas cap is not venting.

you could also have a smog station test the cap but it would cost more to do that test than to simply replace the cap. if you still have the problem after the cap is replaced, then take it to a dealer to have them check the tank vent system called ORVR. you can't do that test yourself because of the location of the valve and the test equipment you would need to do the tests.

I'm pretty sure replacing the gas cap will fix the car. be sure to use the factory cap and not one from a parts store because the fit and seal of the original is critical to the emissions system operation.

hope that helps

Answer 2

go to autozone, get a new fuel tank cap for your car. Replace it and the problem should most likely be solved.

Answer 3

if it's the gas cap, replace it. it's because it's losing pressure, meaning not able to hold pressure. let's hope it's not a sensor or electrical thing.