0385133 JOHNSON SPARK PLUG, V40ffm

System Operation
The 3176 Diesel Truck Engine was designed from the beginning for electronic control. The injection pump, fuel lines and nozzles used in traditional Caterpillar engines have been replaced with an electronic unit injector in each cylinder. A solenoid on each injector controls the amount of fuel delivered by the injector. An Electronic Control Module (ECM) sends a signal to each injector solenoid, to provide complete control of the engine.Electronic Controls
The 3176 Diesel Truck Engine electronic system consists of two main components: the Electronic Control Module (ECM) and the Personality Module. The ECM is the computer which controls the 3176 engine. The Personality Module is the software which controls how the computer behaves (the personality module stores the operating maps that define horsepower, torque curves, rpm, etc.). The two must be used together: neither can do anything by itself.The ECM determines a "desired rpm" based on the throttle signal, vehicle speed signal (only while in cruise control), PTO switches (only while in PTO) and certain diagnostic codes. The ECM then maintains the desired engine rpm by sensing actual engine rpm and deciding how much fuel to inject in order to achieve the desired rpm.Fuel Injection
The ECM controls the amount of fuel injected, by varying signals to the injectors. The injectors will inject fuel ONLY if the injector solenoid is energized. The ECM sends a 100 volt signal to the solenoid to energize it. By controlling the timing and duration of the 100 volt signal, the ECM can control injection timing and the amount of fuel injected.The ECM sets certain limits on the amount of fuel that can be injected. "FRC Fuel Pos" is a limit based on boost pressure to control the fuel-air ratio, for emissions control purposes. When the ECM senses a higher boost pressure (more air into cylinder), it increases the "FRC Fuel Pos" limit (allows more fuel into cylinder). "Rated Fuel Pos" is a limit based on the horsepower rating of the engine. It is similar to the rack stops and torque spring on a mechanically governed engine. It provides horsepower and torque curves for specific engine family and rating. All of these limits are programmed at the factory into the Personality Module and are not programmable in the field.Injection timing depends on engine rpm, load and other operation factors. The ECM knows where top-dead-center on cylinder number one is from the signal provided by the engine Speed/Timing Sensor. It decides when injection should occur relative to top-dead-center and provides the signal to the injector at the desired time.Under certain conditions, the 3176 Engine may intentionally operate on just three cylinders. This feature is called "Three Cylinder Cutout" and occurs when the engine is operated under no load, at high rpm (when signals to the injectors are of very short duration). Under these conditions, the ECM does not inject fuel into cylinders 4, 5, and 6. The accompanying change in sound and feel of the engine should not be mis-diagnosed as an engine problem. When more power is needed, all six cylinders will be fueled and full power delivered.Caterpillar Engine Protection
For 7LG7500 and later engines, Caterpillar provides a factory installed Engine Protection system. The Caterpillar Engine Protection system monitors engine oil pressure, coolant temperature, and coolant level. The oil pressure and coolant temperature sensors are standard on all 1992 and newer engines. The Vehicle OEM is responsible for providing the coolant level sensor and the associated harness. The coolant level sensor is the only individually selectable component of Caterpillar Engine Protection. It is ENABLED or DISABLED through a Customer Programmable Parameter.Caterpillar Engine Protection can be programmed to four different modes; OFF, , DERATE, and SHUTDOWN, with the additional option of enabling or disabling the Coolant Level Sensor. Note that all sensors will operate in the Engine Protection Mode selected. For example, if DERATE mode were selected the engine will derate if the Coolant Temperature, Oil Pressure, or Coolant Level (if enabled) Sensors flag the necessary condition. The Coolant Level Sensor can not be selected for , Oil Pressure and Coolant Temperature for DERATE.If Caterpillar Engine Protection is programmed to OFF, the control system disables those diagnostics associated with Caterpillar Engine Protection: Low Oil Pressure, Very Low Oil Pressure, Oil Pressure Sensor Open/Short Circuit, High Coolant Temperature, Very High Coolant Temperature, Low Coolant Level, Very Low Coolant Level, and Coolant Level Sensor Fault. The engine will still use the Coolant Temperature Sensor signal for Cold Mode operation, and the diagnostics available for flagging incorrect sensor operation (Coolant Temp Sensor Open/Short Circuit). The Oil Pressure Sensor signal will be ignored. Because the Oil Pressure Sensor and Coolant Level Sensor (when installed) harness are still present on the engine, the harness could cause a problem in the event it had a short circuit in the supply wire to ground. Therefore, these items should not be excluded from diagnostic procedures.When Caterpillar Engine Protection is programmed to , the control system will only warn the operator of a potential problem by turning on the Warning Lamp solid (continuously on), the Diagnostic Lamp (indicating the presence of an Active diagnostic code), and logging the appropriate diagnostic. The engine will take no further action. For the DERATE mode, the system will first warn the operator with the solid operation of the Warning Lamp as for mode, but, if conditions persist, the control system will go to DERATE mode. During DERATE mode the Warning Lamp will begin to flash, and the available engine power and vehicle speed will be limited. Power will continue to be limited as long as the conditions causing the problem exist. The SHUTDOWN mode causes the system to first go through the DERATE mode just described. If conditions persist the engine will shutdown 30 seconds after the DERATE mode has been entered.Programmable Parameters
Certain parameters that affect 3176 Diesel Truck Engine operation may be changed with electronic service tools (either the ECAP or DDT). The parameters are stored in the ECM, and are protected from unauthorized changes by passwords.These parameters