7744150_078 Volvo.Penta cables and terminals

Starting Choke Position
During start-up, the air/fuel ratio is controlled with the air choke. The starting position depends on the number of cylinders. Typically, the starting choke position is closed 40 to 60 percent.The air choke for the G3606, G3608, and G3612 is maintained at a fixed position until the engine reaches 500 rpm. The air choke for the G3616 is maintained at a fixed position until the engine reaches 700 rpm. If the starting choke position is set too high, the engine will not get enough combustion air. Opening the air choke enables a steady increase of the engine speed until the desired speed is achieved. The setting is especially helpful for starting with parasitic loads, for at high altitudes, or for using non-standard type fuels.The starting choke and the maximum choke position are programmed in Cat ET configuration screen. The starting and maximum wastegate position cannot be changed.Detection of Misfire
Before adjusting the engine, determine whether misfire is present. If misfire is present, the combustion burn time will not be accurate. The misfire will falsely increase the average combustion burn time.Note: Failure to correct the misfire will result in an improper engine setting that will lead to problems.Under normal operating conditions, the combustion burn time is an average value that is displayed by the Advisor display on the remote control panel. The value is displayed in increments of milliseconds (0.001 seconds). The combustion burn time begins when the spark plug ignites. The combustion burn time ends when the flame front reaches the combustion sensor. When a cylinder misfires, the combustion sensor does not detect the flame front. The combustion burn time does not stop until the next cylinder is about to fire. This results in a long combustion burn time. The displayed combustion burn time increases because the time is an average of several ignitions in the cylinder.Cat ET may be used to diagnose misfire. Percent misfire for each cylinder can be displayed in a Cat ET custom status screen.Adjusting the fuel supply in the precombustion chamber on a misfiring cylinder will result in an incorrect setting on the engine. Operational problems will occur.There are two forms of misfire: actual misfire and false misfire.Note: Actual misfire can occur without significantly affecting the exhaust port temperature.The exhaust port temperatures can help to differentiate between actual misfire and false misfire. A low exhaust port temperature probably indicates actual misfire. Troubleshooting can be concentrated on those components that are likely to be causing the misfire. The following components are included:
Check valve for the precombustion chamber
Spark plug
Spark plug extender
Ignition coil
Integrated Sensing Module (ISM)
Needle valve for the precombustion chamber
Gas supply line for the precombustion chamber
Gas Admission Valve (GAV)
Precombustion chamber coolant leaksFalse misfire occurs when the combustion burn time is not measured correctly but the exhaust port temperatures are normal. False misfire indicates a problem with one of the following components: combustion sensor, extender for the combustion sensor, wiring for the combustion sensor and ISM. These components are also susceptible to electrical noise.Electrical noise in the feedback system can cause the combustion burn time to be incorrectly measured. This results in combustion burn times that are too fast. The electrical noise stops the timer before the flame front passes by the combustion sensor.Excessive oil in the cylinder will also cause fast combustion burn times and higher exhaust port temperatures.If the wiring from the combustion sensors to the ISM is not connected correctly, false misfire can be indicated. The exhaust temperatures will be normal but the combustion burn times can be too long because the ISM is not receiving the correct firing order.To isolate the component that is affecting the combustion burn times, components from a suspect cylinder can be exchanged with components from other cylinders. Operate the engine to locate the component. The misfire will follow the component to one of the other cylinders.G3600 Tuning Procedure
Before starting the tuning procedure, complete the following requirements:
The latest released versions of Cat ET and GERP
Calibrated emissions analyzer
Current site-specific fuel sampleThe G3600 A4 engine is tuned to a specific NOx target value that depends on the engine emissions rating. The target value is for tuning purposes. The target value provides some degree of offset below the Not-to-Exceed NOx rating to ensure compliance with the published engine rating. Always tune to one of the following recommended NOx targets with the emissions analyzer set to the uncorrected O2 scale:
30 ppm for 0.3g/hp-hr
50 ppm for 0.5 g/hp-hr
Illustration 1 g06223838Note: The engine speed and load must be greater than 750 RPM and 50% Load to tune, however always tune the engine to the highest load and speed obtainable.Engine misfire must be corrected before proceeding with this adjustment. Tuning the engine with misfire present will result in an engine fuel flow that is too high in the misfiring cylinders, resulting in unbalance cylinder combustion. The engine might have the correct emissions but it will not run smoothly. Misfire is determined from engine spark plug cylinder number misfire rate in Cat ET.If the engine misfire rate is greater than 5% correct the cause of the misfire before continuing on.Follow these steps for the G3600 A4:
Illustration 2 g06223885
Enter the Fuel Specific Heat Ratio, LHV, and Specific Gravity to the values indicated by the gas analysis entered into Caterpillar software GERP to obtain the correct values.
Before you start the engine, prepare to connect an emissions analyzer to the exhaust outlet. Make sure that the emissions analyzer is correctly calibrated. The pickup must extend into the exhaust stream for at least 10 cm (4 inch). Do not connect the anal