I recently purchased a 97 blazer ls for my son it seemj to run great and looked good He noticed the fuel gauge didnt work so he was careful to keep gas in it. He put about 15 gallons in drove it and noticed a gas puddle under the truck but nothing dripping. So I pulled the tank checked for leaks no leaks put in new fuel pump with sending unit new fuel lines and clamps and new gas cap.Drove the thing for one day after putting in 30 bux of gas and after about ten miles gas is just pouring out from under truck.I undo the gas cap and relieve the pressure in tank and it stops leaking.took it to an auto repair facility and they replaced the fuel filter amd upgraded the spider injector to the newer MFI type. well it got put back together and it ran great for 30 min then gas was pouring out of something he called an evap purge solonoid it is right above the rear axle mounted on the frame.WHAT IS CAUSING THIS???? Weve had the truck for two months and its been at the shop for three weeks. Is it possible the charcoal canister is the root of all my problems?

 

It's involved in it, that's probable. Whether the CAUSE or not, that for the guy at the auto repair facility.
But I'm not sure about him, either.

One thing I know from way over here is that neither the Fuel filter or the injector spider WERE causing the problem

 

tanks vent solenoids probably bad. i would put a gas cap on it too seeing how it should have vented before pressure got that high yikes. napa sells the vent solenoid, the one underneith above the diff. have to check the vapor canister too, if liquid fuel in it need a new one too or bone yard.

 

well after some searching we traced problem to the fuel lines were reversed the supply was routed into the vent and vise versa causing excessive pressure to build in tank until gas spewed out of the purge solonoid have since corrected the problem ordered new charcoal canister but have not tripped any codes yet glad to say the truck is back on the road running fine will see if i get any improved performance or milage with the new MFI injector will keep posted thanx to all that offered help

 

As mentioned, if the purge canister had raw fuel in it, replace it. They are not designed to handle liquid fuel.