| Tools Needed | ||
| Part Number | Part Name | Quantity |
| 1U-5470 or 198-4240 |
Engine Pressure Test Group or Digital Pressure Indicator |
1 |
Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group " for the instructions that are needed to use the 1U-5470 Engine Pressure Group. Refer to Operation Manual, NEHS0818, "Using the 198-4240 Digital Pressure Indicator " for the instructions that are needed to use the 198-4240 Digital Pressure Indicator .
The efficiency of an engine can be checked by making a comparison of the pressure in the inlet manifold with the information given 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 listed in the TMI. Development of this information is performed under the following conditions:
- 99 kPa (29.7 in Hg) dry barometric pressure
- 29 °C (85 °F) outside air temperature
- 35 API rated fuel
On a turbocharged engine, a change in the fuel rating will change the horsepower. A change in the fuel rating will change the inlet manifold pressure. If the fuel is rated above 35 API, the inlet manifold pressure can be less than the pressure given in the TMI. If the fuel is rated below 35 API, the inlet manifold pressure can be more than the pressure listed in the TMI.
Note: Ensure that the air inlet and the exhaust are not restricted when you check the inlet manifold pressure. Refer to Testing and Adjusting, "Air Inlet and Exhaust System - Inspect" for more information.
 |
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere. |
 |
Use the following procedure in order to use Caterpillar Electronic Technician (ET) to measure the inlet manifold pressure:
- Connect Cat ET.
- Operate the engine under the suspect conditions.
- Record the value.
- Compare the value that was recorded in Step 3 to the pressure that is given in the TMI.
Use the following procedure in order to use the 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator to measure the inlet manifold pressure:
- Connect the 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator to the inlet manifold at the pressure test location.
 | |
| Illustration 1 | g01121251 |
Pressure test location on the inlet manifold (1) Pipe plug | |
- Operate the engine under the suspect conditions.
- Record the value.
- Compare the value that was recorded in Step 3 to the pressure that is given in the TMI.