12621 Mercury COVER, OIL PAD NON OIL INJECTION

Engine Vibration Troubleshooting
The troubleshooting chart provides a definite sequence to be followed for a logical procedure to determine the frequency and amplitude of vibration so that the source of the vibration can be located and corrected.1. The customer must be asked questions to determine whether his complaint is valid, or whether his diagnosis of the actual problem is correct.Some of the questions that must be asked are as follows:a. What components are vibrating?b. In what speed range does this vibration become excessive?c. Does clutch operation affect the vibration?d. What is the history of the problem?2. Run the engine through the idle speed range and note all vibrating components. Look for any loose or broken mounts, brackets, and fasteners. Repair and tighten any fixtures.3. Check idle speed range with clutch disengaged. If vibrations subside, there is a balance problem with the clutch disc. The clutch disc must be repaired or replaced.4. Further analysis requires the use of a vibration instrument. Any instrument which can accurately measure the displacement of the vibration (usually in mils-inch/1000) and the frequency (cycles per second) will be sufficient. The 4C3030 Vibration Analyzer Group can be used to provide a quick and complete identification of all vibration frequencies present in a constant speed measurement. Make reference to Operation Manual, Form No. NEHS0525 for additional information for troubleshooting vibration complaints with the 4C3030 Vibration Analyzer Group. The following steps assume the use of a vibration instrument such as the IRD Mechanalysis Model 320 or an equivalent instrument can be used to analyze vibration. Make reference to Special Instruction, Troubleshooting Engine Vibration In Vehicular Equipment, Form No. SEHS7914 for additional information for troubleshooting vibration complaints.5. Measure vibration of cab components which have the objectionable vibration.Run engine slowly through the speed range and measure vibration with the instrument filter OUT. When peak amplitudes are found, run the engine at the speeds they occur and with the instrument filter IN, find the frequency of the vibration.If the frequency of vibration is 1/2 times of engine rpm (1/2 order), the vibration is caused by a cylinder misfiring. This must be corrected before further vibration analysis is made.If the frequency of vibration is 3 times engine rpm (3rd order), no corrective action can be taken on the engine because this is the firing frequency of the 3176 Engine. The problem is in the cab or chassis resonance.If frequency is some order other than 1/2 or 3rd order vibrations, then further measurements must be made on the engine.6. Measurements taken on the engine must be made perpendicular to the crankshaft at the front and rear of the engine in vertical and horizontal directions.7. Record all vibrations over 4.0 mils and the engine rpm at which it occurs (100 rpm intervals are sufficient) with instrument filter OUT. Note any sudden increase and decrease in amplitudes. These occur in resonant speed ranges.If no amplitudes exceed 4.0 mils, the engine is within Caterpillar Specs.If amplitudes exceed 4.0 mils, the vibrations must be measured with the instrument filter IN to obtain the frequency of the vibrations.8. Run the engine at high idle. With the instrument filter IN, check the frequency range and record any amplitudes over 4.0 mils and the corresponding frequency. Analysis of vibrations for the possible causes is done by identifying the frequency of the vibration and where on the engine it is the greatest magnitude.Engine Vibration Troubleshooting Electronic Control System
General Information
Various sensors feed engine and vehicle data to the electronic control module (ECM). The standard "package" of sensors monitor engine rpm and timing, throttle position, coolant temperature, boost pressure, vehicle speed, cruise control switches status (on/off and set/resume), clutch switch, brake switch, and parking switch. The ECM processes this data and sends electronic signals to the fuel injector pump solenoids. The solenoids are energized and deenergized to start and stop, respectively, the fuel discharge from the fuel injection pumps. See the topic, Electronically Controlled Unit Injector, for a complete explanation of the fuel injection process.Data Link
The engine incorporates a DATA LINK intended for communication with other microprocessor based devices that are compatible with the proposed American Trucking Association (ATA) and SAE standard. The DATA LINK follows SAE recommended practice J1708 for the hardware description and recommended practice J1587 for the data protocol.The DATA LINK can reduce duplication of truck sensors by allowing controls to share information. The DATA LINK is used to communicate engine information to other electronic vehicle control systems and to interface with Caterpillar service tools [Electronic Control Analyzer and Programmer (ECAP) and Digital Diagnostic Tool (DDT)].The engine/vehicle information that is monitored and available on the DATA LINK include the following:Boost PressureCold Start StatusCoolant TemperatureCruise Control StatusCruise Control Set SpeedEngine IdentificationEngine Systems StatusEngine Speed-rpmFault ParameterFuel Consumption RateIdle Shutdown Timer StatusCalibration (road speed limit-mph, cruise control high speed set limit, cruise control low speed limit, PTO high limit)Fuel PressurePercent ThrottlePTO Control StatusPTO Control Set RPMRetarder Enable StatusCalibration (rated speed-rpm and rated power-bhp)Vehicle Speed-mphVehicle Speed Limit StatusEither the Electronic Control Analyzer and Programmer (ECAP) or the Digital Diagnostic Tool (DDT), can be used to program the customer specified parameters.One method of programming the customer specified parameters that are selected by a customer, the Electronic Control Analyzer and Programmer (ECAP), is used. The tool plugs into the data link connector to communicate with the ECM. The (ECAP) can be also be used to display real time values of all information available on the data link for diagnosing engine problems.
ECAP Connection To The Data Link
(1) J8 Connector (of the Data Link to the ECM). (2) ECAP. (3) P8 Connector (of the Data Link to the cab). (4) "T" Harness (8T5275)To read or reprogram the customer specified parameters, or test the electronic control system for faults, an ECAP service tool must be connected to the Data Link. See Electronic Troubleshooting, Form No. SENR3913, for a complete explanation of this connection and the functions of the ECAP.Programming of the customer specified parameters can be password protected to prevent unauthorized tampering or changing of the customer selected limits.