If you are using your own Buttkicker or DIY shakers and have no engine effects when in a game, increase the Engine effect slider in the TUNING > Shake page.
In addition, if using a Advanced Shaker Profile, ensure the channel volume for the effect is high enough to feel the shaking. Usually a setting of 10 to 15 will allow any shake effects to be felt. These can be adjusted for each channel by clicking the gear icon to the right of the Test button for each channel in the SETUP > Shakers section.