C 2500 3/4 Ton Pickup 2WD L6-250 4.1L VIN D 2-bbl (1984)
Canister Purge Solenoid: Description and Operation
Fig. 72 Charcoal canister with solenoid operated purge valve
Some engines equipped with Computer Command Control (C-3) and V6 engines with Throttle Body Injection (TBI) use an ECM operated solenoid to
control canister purge vacuum, Fig. 72. The ECM completes the solenoid ground path, energizing the solenoid to block purge vacuum and de-energizing
the solenoid to allow the canister to be purged. The ECM energizes the solenoid during cold engine operation, at idle and when the vehicle is stopped
with the engine running. The ECM de-energizes the solenoid and allows canister purge during normal engine operation, with the throttle open and road
speed above approximately 5 m.p.h..
