0330549 JOHNSON BY-PASS COVER ASSY.

The electronic engines that are covered by this manual have the following characteristics: direct fuel injection, electronic unit injection that is mechanically actuated, turbocharged and aftercooled.The electronic engine control system provides the following functions: electronic governing, automatic air to fuel ratio control, torque rise shaping, injection timing control and system diagnostics.An electronic governor controls the output of the unit injectors in order to maintain the engine rpm that is desired. The functions of the governor include a programmable low idle and a 20 rpm to 200 rpm governor overrun.Very high injection pressures are produced by electronically controlled, mechanically actuated unit injectors. The injectors combine the pumping and the electronic fuel metering (duration and timing) during injection. The unit injectors accurately control smoke limiting, white smoke, and engine acceleration rates.There is one unit injector per cylinder. Individual unit injectors meter the fuel. The individual unit injectors also pump the fuel. The metering and the pumping is done under high pressure. High injection pressures help to reduce fuel consumption and emissions. The use of this type of unit injector provides total electronic control of injection timing. The injection timing varies with engine operating conditions. The engine performance is optimized in the following areas:
Starting
Emissions
Noise
Fuel consumptionThe timing advance is achieved through precise control of the injector firing. Engine speed is controlled by adjusting the firing duration. The information is provided to the Electronic Control Module (ECM) by an engine speed/timing sensor. The information is for detection of cylinder position and engine speed.The engines have built-in diagnostics in order to ensure that all of the components are functioning and operating properly. In the event of a system component deviation from the programmed limits, the operator will be alerted to the condition by a DIAGNOSTIC lamp that is mounted on the control panel. An electronic service tool that is provided by Caterpillar may be used to read the numerical code of the diagnostic flash code. There are three types of diagnostic codes: ACTIVE, LOGGED and EVENT. These codes are logged and stored in the ECM. Refer to the Operation and Maintenance Manual, "Engine Diagnostics" for additional information.The cooling system consists of the following items: a centrifugal pump that is driven by a gear, water temperature regulator, an oil cooler and an aftercooler.The engine lubricating oil is supplied by a gear type pump. The engine lubricating oil is cooled and filtered. Bypass valves provide unrestricted flow of lubrication oil to the engine parts when the oil viscosity is high or if either the oil cooler or the oil filter elements (paper cartridge) become plugged.Engine efficiency, efficiency of emission controls, and engine performance depend on adherence to proper operation and maintenance recommendations. This includes the use of recommended fuels, coolants and lubrication oils.Aftermarket Products and Cat Engines
Caterpillar requires the use of a 4 micron(c) secondary fuel filter for the following reasons: to maximize fuel system life and to prevent premature wear out from abrasive particles in the fuel. Cat high efficiency fuel filters meet these requirements. Consult your Cat dealer for the proper part numbers.
When auxiliary devices, accessories, or consumables (filters, additives, catalysts, etc.) which are made by other manufacturers are used on Cat products, the Caterpillar warranty is not affected simply because of such use.However, failures that result from the installation or use of other manufacturers' devices, accessories, or consumables are NOT Caterpillar defects. Therefore, the defects are NOT covered under the Caterpillar warranty.Welding and Cat Electronic Engines
Because the strength of the frame may decrease, some manufacturers do not recommend welding onto a chassis frame or rail. Consult the OEM of the equipment or your Cat dealer regarding welding on a chassis frame or rail.
To help avoid damage to the electronic controls, proper welding procedures are necessary. Before welding on a vehicle that is equipped with an electronic engine, observe the following precautions:
Turn off the engine. Place the key start switch in the OFF position.
If the application has a battery disconnect switch, open the switch. Otherwise, disconnect the negative "-" battery cable from the battery of the vehicle.
Do not ground the welder to electrical components such as the ECM or sensors. Improper grounding can cause damage to the drive train bearings, hydraulic components, electrical components, and other components.Clamp the ground cable from the welder to the component that will be welded. Place the clamp as close as possible to the weld. This will help reduce the possibility of damage.
Clamp the ground cable from the welder to the component that will be welded. Place the clamp as close as possible to the weld.
Protect wiring harnesses from welding debris and from spatter. Use proper welding procedures.Special-Purpose Enginge (SPE) Certification
In the European Union (EU), these engines are type approved to the requirements for special-purpose engines, in accordance with Article 34(5) of Regulation (EU) 2016/1628. As such, they are restricted to use in potentially explosive atmosphere, as noted on the EU type-approval certificate.