Possible Causes & Corrections

Check the following items:

• Check fuel quality.
• Check fuel injection pump and timing. See appropriate ON-VEHICLE ADJUSTMENTS article.
• Observe the actual vs. desired fuel rail pressure with a scan tool, with the engine running.
• Check injector nozzles. See appropriate SYSTEM & COMPONENT TESTING article.
• Check Engine Coolant Temperature (ECT) sensor. Reading should be within 5°F of ambient air temperature on a cold engine.
• Inspect the glow plug system operation.
• Inspect the Fuel Rail Pressure (FRP) sensor. Use the scan tool to observe FRP with the engine off. FRP should be 1.1-1.4 MPa. If not, inspect for high resistance in the low reference or 5-volt reference circuits or the sensor.
• Check air filter, turbocharger and air intake system for a restriction.
• Inspect for contamination of the Mass Air Flow (MAF) sensor.
• Perform the engine compression test and a cylinder leakage test.
• Inspect the Intake Air Heater (IAH) for proper operation. Use a scan tool to command the IAH on and off.
• Check for incorrect basic engine parts such as camshaft, cylinder heads and pistons.
• Check for excessive blow-by.
• Inspect for coolant entering the combustion chamber.