ENGINE AR. 9L3653 - Caterpillar

Illustration 9 g03019890
The turbo outlet absolute pressure and torque converter temperatures are shown for each test in Illustration 8 and Illustration 9. Atmospheric pressure is plotted with the turbo pressure to calculate boost pressure. Boost pressure equals turbo outlet – atmospheric pressure. The boost pressure is also recorded in Table 7.The engine response time, stall speeds, and boost pressure should not significantly change over the engine life. If these parameters do significantly change, further investigation and testing of the engine, transmission, torque converter, and hydraulic systems are warranted.
Table 7
Typical Steady State Values During Converter Stall and Double Stall Tests    
    Engine Speed     Boost Pressure     Response Time (min-max engine speed)    
Converter Stall     1520 25 RPM     16 1 psi     7 1 sec    
Double Stall     1150 25 RPM     12 1 psi     N/A    Possible Causes for changes in engine response, stall speeds, and boost pressure
Leak in exhaust system
Leak in air inlet system
Failed fuel injector
Failed valve
Restriction in air inlet and exhaust system
Failed turbo pressure sensorExhaust Temperature Split
Illustration 10 g03019894
Illustration 11 g03019898
Exhaust temperature split is the difference between the right and left exhaust temperature taken at the same time. The exhaust temperature split data is only meaningful during full load conditions. The engine is under a full load for the converter and double stall tests. The Illustrations 10 and 11 respectively show the exhaust temperature split during the converter and double stall tests.There is normally some difference between the left and right exhaust temperatures, typically less than 20° C (36° F). If the exhaust temperature split is greater than 50° C (90° F) or a step change in the exhaust temperature split occurs, this may indicate a serious problem.Possible Causes for a High Exhaust Temperature Splits:
Failed fuel injector
Leak or break in fuel line between fuel manifold and cylinder head
Wrong valve clearance
Leak in air inlet system
Leak in exhaust system
Restriction in air inlet or exhaust system
Wrong fuel injector lash
Incorrect fuel injection timing calibration
Bent or broken push rod
Failed exhaust temperature sensorTest 6: Impeller Clutch Pressure Test Impeller Clutch Pressure vs. Left Pedal
Illustration 12 g03019916
The left pedal controls the impeller clutch pressure. Based on the left pedal position, the transmission electronic control module activates the impeller clutch solenoid valve. The impeller clutch solenoid valve controls the oil flow to the impeller clutch. The left pedal acts as an on/off switch at approximately 40 percent pedal travel. When the pedal crosses this threshold, the impeller clutch pressure is reduced which limits the torque being transmitted by the torque converter. In the last 60 percent of pedal travel, the service brakes are engaged. This relationship can be verified by gradually depressing the torque converter pedal through the pedals entire travel. A typical run at high idle is shown in Illustration 12, and the results are recorded in Table 8. The Table 8 shows the relationship between left pedal position and impeller clutch pressure at an engine speed of 1675 RPM. The initial impeller clutch