Cause
• Air intake or exhaust restriction
• Turbocharger failure, turbocharger blade damage or turbocharger wheel stuck
• Loose or failed injector
• Altitude (black smoke on hard acceleration or snap acceleration may be more pronounced at higher elevations)
• Failed Manifold Absolute Pressure (MAP) sensor
• Failed Exhaust Back Pressure (EBP) sensor
• Failed Injection Control Pressure (ICP) sensor
Procedure
1. If engine has fuel knock or there is evidence of fuel in the exhaust, remove exhaust manifolds and inspect for fuel in the exhaust ports. (Suspect loose injectors, missing or damaged O-ring and gasket on bottom of injector).
2. Inspect air inlet system and exhaust system for possible sources of restriction.
3. Inspect turbocharger for oil leakage or failure of blades.
4. Do Test 7 (Intake Restriction) on Performance Diagnostics form or in Section 6 of this manual.
5. Do Test 8 (Exhaust Restriction) on Performance Diagnostics form or in Section 6 of this manual.
