CAP-DUST 2018552 - Caterpillar

(9CK) Truck EnginesPopping noises can be generated by the turbocharger for different reasons. Because the 1994 engines have higher boost levels and low inertia turbochargers, the popping noise is generated in a different manner.
When the engine is developing moderate to high power levels and the throttle pedal is suddenly released, the boost pressure will reduce the turbocharger speed. The boost pressure then goes back through the compressor housing causing a popping or swishing sound. Two conditions that cause the popping sound are a rapid release of the throttle or disengaging the cruise control.
The popping sound caused by these conditions has not caused any failures.