15 - Boost Pressure Test

15. Boost Pressure Test





Purpose:
To determine if the engine can develop sufficient boost to obtain specific power.

If the engine can obtain specified boost there is no engine power problem. There may be chassis or applications concerns but the engine is performing as specified.

Recommended Procedure:
Monitor NGS PID "MGP" After the engine is up to operating temperature, find an open section of road and select the best gear to achieve a 2500-3000 rpm acceleration. With the accelerator at wide open throttle, note the boost reading while accelerating through the 2500-3000 rpm range. Boost will level out after 3000 rpm. The highest boost reading will be noticed between 2500-3000 rpm. This test is best accomplished either climbing a hill or with the truck fully loaded.





Alternate Procedure:
Install a T (manufactured locally out of common fittings) into the Manifold Absolute Pressure (MAP) sensor line that comes from the intake manifold. Make sure the MAP sensor is hooked up for this test.

Connect the T to a 0-30 psi gauge that is temporarily installed in the cab. Route the hose so that it is not crimped and does not come in contact with any hot surface.

Possible Causes:
- Restricted intake or exhaust
- Pinched or open MAP sensor hose
- Low fuel pressure
- Biased MAP sensor
- Low injection control pressure
- Control system faults
- IDM fault
- Defective injectors
- Defective turbocharger
- Base engine failure

Tools Required:
- A T manufactured locally out of common fittings
- 0-30 psi gauge
- New Generation Star Tester 007-00500 or equivalent