Does anyone have any idea how a canister purge solenoid works on a 93 F150 with a 302. Mine seams to going on and off all the time. It makes the truck sound as if it has a bad spark knock as you accelerate. Is the solenoid supposed to come on and stay on? Or is supposed to cycle on and off? Any help would be greatly appreciated. Thanks

 

It's working normally. Fuel vapor from your gas tank is collected and stored in the charcoal canister. When engine operating conditions are right the ecm will turn on the purge solenoid. It's pulse width modulated so it will make a constant clicking noise. When the canister is purged, or when something changes with the engine (heavy acceleration for example) the solenoid will shut off. So if you let the truck sit and idle for awhile it is normal for that solenoid to come on every few minutes.

-Jon

 

Thanks for the info