Hiss when I open gas cap.
05-28-2012, 10:55 PM
#1
Hiss when I open gas cap. Ok I recently purchased a 96 Z with 72k on it and when I go to fill the tank I get a LOUD hiss when I open the gas cap. From my research it seems the evap system might be plugged up? Possibly the evap canister? Sooo has anybody else had this problem and if so how do I go about fixing this?
Thanks guys!
Thanks guys!
05-29-2012, 04:40 AM
#7
Lets clarify here.
I little of hiss is normal. A lot of it is not because excessive pressure in a fuel tank is not good for obvious reasons. When mine did it too much, it would hiss loudly for 5-6 seconds when the capp was pulled plus I could here it weezing through the threads on the gas cap.
If the EVAP line from the EVAP cannister to the intake is clogged up, you will end up with excessive pressure in the tank. Their is a filter in the top of the cannister and over time it tears and allows small charcoal particles into the long plastic line and possible into the solenoid on the right side of the intake. If this happens you have to clean the clog and the solenoid plus replace the cannister if you want the EVAP to work as designed. The plastic line that loops around the front of the intake is very difficult to clean out and sometimes the solenoid may need to be replaced too. This has happened to me once so I keep a cannister on hand plus one day soon I would like to put a small inline filter on the line just after the cannister to prevent the chunks from making their way up front.
To check for a clog, pull he line off of the solenoid on the right side of the intake and hook up a vaccum pump and see if it draws air. If it does draw, the line is clear and there may be an issue with the solenoid. If it does not draw, its clearly clogged. If you dont have a pump, you can suck it by mouth to test but dont tell your friends.
Or you can delete the entire EVAP system all together but you will need to ensure the tank is allowed to vent to atmosphere. Also you will smell gas around the car kind of like it used to be in the old days.
Regardless, address ASAP it so you dont run into a safety problem in the event of a collision.
I little of hiss is normal. A lot of it is not because excessive pressure in a fuel tank is not good for obvious reasons. When mine did it too much, it would hiss loudly for 5-6 seconds when the capp was pulled plus I could here it weezing through the threads on the gas cap.
If the EVAP line from the EVAP cannister to the intake is clogged up, you will end up with excessive pressure in the tank. Their is a filter in the top of the cannister and over time it tears and allows small charcoal particles into the long plastic line and possible into the solenoid on the right side of the intake. If this happens you have to clean the clog and the solenoid plus replace the cannister if you want the EVAP to work as designed. The plastic line that loops around the front of the intake is very difficult to clean out and sometimes the solenoid may need to be replaced too. This has happened to me once so I keep a cannister on hand plus one day soon I would like to put a small inline filter on the line just after the cannister to prevent the chunks from making their way up front.
To check for a clog, pull he line off of the solenoid on the right side of the intake and hook up a vaccum pump and see if it draws air. If it does draw, the line is clear and there may be an issue with the solenoid. If it does not draw, its clearly clogged. If you dont have a pump, you can suck it by mouth to test but dont tell your friends.
Or you can delete the entire EVAP system all together but you will need to ensure the tank is allowed to vent to atmosphere. Also you will smell gas around the car kind of like it used to be in the old days.
Regardless, address ASAP it so you dont run into a safety problem in the event of a collision.
