Make and model of valve? (or a photo)
One station in our sprinkler system is having a problem I've never encountered before. It works perfectly when manually opened at the local vault box, but when activated by the automatically timed control box there is significantly less pressure, such that the pop ups do not rise up much. Any suggestions will be much appreciated.
The manual and automatic methods operate differently. If the automatic method does not "dump" water fast enough, or if it is damaged internally so the water is being replenished as it is dumped, then it will not open entirely. Manual operation usually can overcome any bypassing internal leakage and open all the way. You may have a bad diaphragm, weak solenoid, restricted solenoid water passages, etc.
Or the solenoid plunger can't fully retract anymore because rust or crud has accumulated in the shaft. I'd take it off and look.