Gas leak or Tank Purge?

[gmcsierra01]

any idea what will cause this? when i turn the key to the on position so the fuel can pressure up I can hear like an air leak is it because the tank is getting purged ? or is there a leak but I dont smell no gas vehicle is a 01 gmc sierra 1500 v8 5.3l

[ChevyTech007]

Are you sure you are not just hearing the fuel pump running. It will kick on for 2 seconds.

[gmcsierra01]

well after the pumps kick in and stops I can hear the leak I even took down the gas tank to try and find the leak but no luck only to find out the gas tank is plastic.

[ChevyTech007]

I would not worry about it. It could be a purge function. If there is a leak you would have a SES light on. The ECM does many test on the evap system. If you had a leak believe me, you would have a light on. It can detect a VERY small leak. I say let it ride.

[gmcsierra01]

thanks for the info