Definition of quantal. 1  1 [Latin quanti how many, plural of quantus] : of, relating to, or having only two experimental alternatives (such as dead or alive, all or none) 2  2 [quantum] : of or relating to a quantum.
3. Engine movement. Another symptom of bad or failing engine mounts is an engine that moves in the engine bay. If the engine mounts are in good condition, they should be able to secure the engine firmly in the engine bay.
- Common Symptoms. A failing fuel pump will not create enough pressure in the fuel system, potentially resulting in a loss of engine power or a no start condition. You may also have a lean running condition that can set a diagnostic trouble code and turn on the Check Engine Light. failing fuel pump will not create enough pressure in the fuel system, potentially resulting in a loss of engine power or a no start condition.