Evaporative canister

Why is it difficult and slow to fill the fuel tank on a 1999 gmc sierra and can this be repaired by a handy but ignorant owner?

The problem might be with the Onboard Refueling Vapor Recovery system.

Unlike in the old days when a tank was vented while refueling thru either a seperate vent hose or with a hose-in-hose vent system, the tank must first vent thru the carbon canister before being allowed into the atmophere. And the hoses from the gas tank to the carbon canister are the first to remove and blow out with compressed air.

There have even been reports of spiders building nests in these systems causing this problem.


Cure some of the ignorance by going to the Web, and to the repair manuals, and bone up on EVAPORATIVE Recovery System, and Onboard Refueling Recovery Systems. Then, armed with knowledge, you can tackle the problem.

“Onboard Refueling Recovery Systems.” Your '99 TRUCK may not have one…In that case, run a flexible rod down the filler neck and try to free up the stuck anti-spill (roll-over) check ball…