2004 5.3/4l60 swap in 84 C10.....does any one know if the purge solenoid valve is suppose to always have vacuum or does the computer kick it on? i have no vacuum on the valve so i can connect the hose to my canister. i tried another solenoid and i do have 12v to the red wire going to it.

 

If memory serves me well (I have very little EVAP experience), the purge solenoid should always have vacuum applied to the engine side (assuming the engine is running, of course). The PCM opens the purge solenoid to allow the EVAP system to apply vacuum to the canister/tank.

 

thanks, yes that is what im looking for, vacuum when the engine is running so it can provide vacuum to my canister for emissions.