SPRING-GAS 1166325 - Caterpillar

The efficiency of an engine can be checked. Compare the pressure in the inlet manifold with the specifications in the Fuel Setting And Related Information in the TMI (Technical Marketing Information). This test is used when there is a decrease of horsepower from the engine, yet there is no real sign of a problem with the engine.The correct pressure for the inlet manifold is given in the Fuel Setting And Related Information in the TMI (Technical Marketing Information). The specifications in the Fuel Setting And Related Information in the TMI (Technical Marketing Information) were developed under the following conditions:
98 kPa (29 inches of Hg) (DRY) barometric pressure
29 °C (85 °F) outside air temperature
35 API rated fuelAny change from these conditions can change the pressure in the inlet manifold. Outside air that has higher temperature and lower barometric pressure will result in performance below the specifications in the TMI (Technical Marketing Information). A lower horsepower and a lower inlet manifold pressure measurement will result. Outside air that has a lower temperature and a higher barometric pressure will cause higher horsepower and a higher inlet manifold pressure measurement.On an engine that is turbocharged and aftercooled, a change in the fuel rating will also change the horsepower and the pressure in the inlet manifold. If the fuel is rated above 35 API, the pressure in the inlet manifold can be less than the pressure that is given in the TMI (Technical Marketing Information). If the fuel is rated below 35 API, the pressure in the inlet manifold can be more than the pressure that is given in the TMI (Technical Marketing Information).Note: Be Sure That The Air Inlet And Exhaust System Does Not Have A Restriction When A Check Of The Pressure In The Inlet Manifold Is Being Made.
Illustration 1 g00564676
Pressure Test Location (1) Plug. To measure the inlet manifold pressure, remove one of the plugs. Connect the 1U-5470 Engine Pressure Group to the opening in the aftercooler housing.
Illustration 2 g00296486
1U-5470 Engine Pressure Group This tool group has a pressure indicator in order to read pressure in the inlet manifold. The tool group includes Special Instruction, SEHS8907. Instructions for the tool group's use are contained in Special Instruction, SEHS8907.