Purpose
To determine if the engine develops specified stall rpm within idle to stall time, when diagnosing a poor launch concern
Tools
• None
Procedure
CAUTION: Avoid damage to the drive train. Do not do this test for more than 10 seconds at a time or
more than twice back to back. (If doing twice – wait 2 minutes between tests.)
1. See “DT 466 Performance Specifications” – Appendix A (page 595) and “DT 570 and HT 570 Performance Specifications” – Appendix B (page 619) for specifications and record on Diagnostic Form.
2. Set parking brake and apply service brake.
3. Put transmission in drive.
4. Press accelerator pedal fully to the floor, begin timing and monitor TACH until TACH stops moving.
5. Record stall RPM and idle to stall time on Diagnostic Form.
• If minimum RPM is reached in the specified time, with Performance Diagnostics, for a poor launch concern do not continue with Performance Diagnostics.
• If RPM is low or not reached in the specified time, continue Performance Diagnostics.
Possible Causes
• Intake leaks (hoses, clamps)
• Boost leaks
• Restricted intake or exhaust
• Exhaust leaks
• Low fuel pressure
• Low ICP
• Control system faults
• Failed EGR control valve
• Inoperative fuel injectors
• Failed turbocharger
• Diamond Logic® engine brake malfunction
• Biased BAP, EBP, ICP or MAP sensors
• Power cylinder condition
