CTM100 (06APR04) 04-150-19 P OWER T ECH 10.5 L & 12.5 L Diesel Engines 040604 PN=367 Observable Diagnostics and Tests Check Intake Manifold Pressure (Turbo Boost) The preferred method of measuring intake manifold pressure (turbo boost) is to use the Diagnostic Scan Tool (DST) and read the Manifold Air Pressure (MAP) –UN–26NOV97 parameter when engine is developing rated power at full load rated speed. If the DST is not available, use the procedure below to manually test intake manifold pressure. RG8800 1. Remove ether starting aid assembly adapter or plug from intake manifold cover, as equipped.
Connect Measuring Intake Manifold Pressure pressure gauge to intake manifold using JT05412 Universal Pressure Test Kit. Be sure all connections are tight. 2. Before checking boost pressure, warm up engine to allow the lubricating oil to reach operating temperature. IMPORTANT: Engine speed and load should be stabilized before taking a gauge reading. Be sure that gauge works properly and familiarize yourself with the use of the gauge. 3. Observe pressure reading on gauge. Compare reading to the specifications when engine is developing rated power at full load rated speed. See INTAKE MANIFOLD PRESSURE (TURBOCHARGER BOOST) SPECIFICATIONS in Section 06, Group 210 of this manual.
If boost pressure is too low, check for the following: • Restricted air filter elements. • Incorrect fast idle adjustment. • Exhaust manifold leaks. • Intake manifold leaks. • Low compression pressure. • Carbon build-up in turbocharger. • Turbocharger compressor or turbine wheel rubbing housing. • Restricted exhaust. 4. After completing test, remove test equipment and reinstall plug. Tighten securely. RG,RG34710,1549 –19–24SEP02–1/1 04 150 19