OM3050 7/09 Operating Instructions - Section 30 Page 30-19 SUDDEN LOSS OF ENGINE POWER If the engine suddenly stops, there is enough hydrau- lic pressure stored in the brake and steering accumu- lators to allow the operation of the steering and brake functions. However, this oil supply is limited so it is important to stop the truck as quickly and safely as possible after the loss of engine power. FUEL DEPLETION The high pressure injection (HPI) fuel system uses fuel to adjust fuel delivery timing by creating a hydraulic link between the upper plunger and the timing plunger. Metered fuel is also used for lubricating the injector plunger and barrel.
The maximum demand for metered fuel is required during high speed / low load conditions. If the brake supply pressure drops to a pre-deter- mined level, the low brake pressure warning mes- sage will illuminate and a buzzer will sound. If the brake pressure continues to decrease, the auto- apply feature will activate and the service brakes will apply automatically to stop the truck. 1. Bring the truck to a safe stop as quickly as pos- sible by using the foot pedal to apply the ser- vice brakes. If possible, safely steer the truck to the side of the road while braking. Operating the truck to fuel depletion forces the injector train into a no-follow condition.
No fuel flow between the plungers may cause damage to the injectors and the overhead due to adhesive wear, resulting in costly repairs and unnecessary downtime. Dynamic retarding will not be available! DO NOT use the service brakes for continuous retarding purposes. 2. As soon as the truck has stopped moving, shift the directional control lever to PARK. This will apply the parking brake. Allowing the Komatsu truck to operate until fuel depletion can lead to unsafe operating conditions possibly resulting in an uncontrollable vehicle and/or personal injury. 3. Slowly release the service brakes to check the capacity of the parking brake.
If the parking brake can not hold the truck stationary, apply the service brakes and hold them ON. DO NOT turn the key switch OFF, and DO NOT release the service brakes. 4. Notify maintenance personnel immediately. 5. If the truck is on level ground, or if the parking brake can hold the truck stationary and the truck is in a stable condition, it is then OK to turn the key switch OFF. 6. If safe to do so, have maintenance personnel place wheel chocks or other mechanisms in front or behind the wheels to reduce the risk of the truck rolling. 7. If traffic is heavy near the disabled machine, mark the truck with warning flags during day- light hours or use flares at night.
Adhere to local regulations.