ROD 3220715 - Caterpillar

Inlet Manifold Air Pressure (TA Engines) and Inlet Manifold Vacuum (NA Engines) - For TA engines, this gauge indicates the air pressure (turbocharger boost pressure) in the air plenum (air inlet manifold) after the aftercooler. For NA engines, this gauge is the pressure of the inlet manifold vacuum. For all engines, this pressure is relative to the load. This pressure may be used for estimating power output. Several factors affect the inlet manifold air pressure. All of these factors must be accounted for when power is estimated from inlet manifold air pressure: air restriction, exhaust restriction, jacket water coolant temperature, ambient air temperature, variation of the fuel, air/fuel ratio, ignition timing and condition of the valves.For more information, see the performance curves in the Engine Performance manual. The manual is available from your Caterpillar dealer.
Tachometer - This gauge indicates the engine rpm.
An overspeed can result in serious damage to the engine. To help prevent engine damage, never allow the engine to exceed the rated rpm.
Note: The rated rpm is stamped on the engine Information Plate.
Service Hour Meter - This meter shows the total number of service meter units that the engine has operated. Table 2 lists the factors for converting service meter units to clock hours.
Table 2
Factors for Converting Service Meter Units to Clock Hours
Operating Speed Factor
Engines That Are Rated From 1000 RPM to 1400 RPM
1000 rpm 1.200
1200 rpm 1.000
1400 rpm 0.857
Engines That Are Rated From 1500 RPM to 1800 RPM
1500 rpm 1.200
1600 rpm 1.125
1800 rpm 1.000 For example, an engine that is rated at 1800 rpm has been operating at 1500 rpm. To determine the number of clock hours, multiply the number of service meter units by the correct factor. In this example, one service meter unit is equivalent to 1.2 clock hours.
Fuel Filter Differential Pressure - This gauge is provided by the customer. This gauge indicates the difference in fuel pressure between the inlet side and the outlet side of the fuel filter. As the fuel filter element becomes plugged, the difference in pressure between the two sides of the fuel filter increases.Service the fuel filter when the fuel filter differential pressure reaches 34 kPa (5 psi).
Air Cleaner Differential Pressure - This gauge indicates the difference in air pressure between the inlet side and the engine side of the air filter element. The pressure is measured from the turbocharger air inlet. As the air filter element becomes plugged, the difference in pressure between the two sides of the air cleaner element will increase. For optimum engine performance, replace the air cleaner elements when the air cleaner differential pressure reaches 4 kPa (15 inches of H2O). Maximum air cleaner differential pressure is 7.5 kPa (30 inches of H2O).
Ammeter - This gauge indicates the amount of charge or discharge in the battery charging circuit. Operation of the indicator should be to the right side of "0"(zero).
Engine Oil Temperature - This gauge indicates the engine oil temperature after the oil has passed through the oil cooler. The maximum oil