Question

when the throttle is snapped wide open during a running compression test, what reading should be seen for a normal cylinder?
select one:
o a. about 50% of the cranking compression pressure
o b. about two - thirds of the cranking compression pressure
o c. about 80% of the cranking compression pressure
o d. equal to the cranking compression pressure

Explanation:

During a running compression test, when the throttle is snapped wide open, for a normal cylinder, the reading should be about two - thirds of the cranking compression pressure. This is based on the principles of engine operation and compression testing. When the engine is running and the throttle is wide open, the conditions are different from cranking (engine not running, just being turned over by the starter). The running compression is affected by factors like valve timing, engine speed, and air flow dynamics. In a normal cylinder, the running compression is typically around two - thirds of the cranking compression.

Answer:

b. About two - thirds of the cranking compression pressure