101691-9924 ZEXEL INJECTION-PUMP ASSEMBLY Cross 1016919924 1671395161

Operation-Jacobs Brake
The Jacobs Engine Brake should not be used as a primary or service brake.Do not allow the engine to exceed 2300 rpm. However, engines equipped with a Jacobs Engine Brake should not be operated above 2100 rpm.
The Jacobs Engine Brake is an engine attachment that converts a diesel engine into an air compressor. Its function is to slow the vehicle and reduce brake wear.Operating Controls-Jacobs Brake
The Jacobs Engine Brake controls may include a dash mounted module or an ON/OFF switch and a three position switch with "Lo," "Med" and "Hi" depending on how many cylinders of braking desired. Refer to your truck manufacturer's Owner Manual for the type of operating controls that your vehicle is equipped with.The 3176 ECM monitors the clutch, brake, throttle position and engine rpm to determine when the Jacobs Brake can operate. It may take up to two seconds before Jacobs Brake activates.Since the Jacobs Engine Brake is most effective at rated engine rpm, gear selection is very important. Gearing down the vehicle, within the limits of rated engine rpm, makes the engine brake a more effective retarder. Maximum retarding occurs at higher engine rpm.Cruise Control (If Equipped) OFF
With the Cruise Control (CC) in the OFF position the Jacobs Engine Brake will function like any vehicle and engine that is not equipped with Cruise Control (CC).Cruise Control (If Equipped) ON
The driver must apply the service brake approximately two seconds and then release the service brake pedal. If the retarder "Latch" mode has been programmed, the retarder will continue to slow the vehicle. To release order activate the retarder, the clutch or throttle foot pedal must be depressed or the engine rpm drop to 950 rpm.When using "Coast" mode, the Jacobs Brake should activate within two seconds after the brake pedal is applied and remain on as long as the brake pedal is applied. At the time the brake pedal is applied, the Cruise Control (CC) will deactivate.For information on adjustment to Jacobs Brake slave piston lash, refer to PM Level 2-Engine Valve Lash. Refer to Jacobs Brake Troubleshooting Manual, Form SENR4251 for information regarding this auxiliary braking system.