Additional Symptoms Tests

Hard Start

• Verify the ECT has not shifted in value. Refer to Temperature Versus Resistance (ECT and IAT) .
• Inspect for a slow cranking speed. Refer to Symptoms - Engine Electrical .
• Verify the engine electrical system for correct operation. Refer to Symptoms - Engine Electrical .
• Verify the driver is using the correct starting procedure as described in the owners manual.
• Inspect for a restriction in turbocharger inlet duct.
• Inspect for a restriction or a leak in the intake manifold.
• Inspect the exhaust system for a possible restriction. Refer to Restricted Exhaust .
• Inspect for excessive crankshaft end play that will cause the CKP sensor reluctor wheel to move out of alignment with the CKP sensor.

Hesitation, Sag, Stumble

• Test the generator. Refer to Symptoms - Engine Electrical . Repair the charging system if the generator output voltage is less than 9 volts or greater than 16 volts.
• Inspect for excessive crankshaft end play that will cause the CKP sensor reluctor wheel to move out of alignment with the CKP sensor.

Poor Fuel Economy

• Heavy loads being carried or towed
• Acceleration rate too much or too often
• Inspect the brake system for brake drag.
• Inspect the tires for the correct air pressure.
• Inspect for incorrect operation of the speedometer.
• Inspect for an air leak in the charge air cooler.
• Inspect the air conditioning system for proper operation.
• Suggest to the owner to fill the fuel tank and inspect the fuel economy.
• Suggest to the driver to read the Important Facts on Fuel Economy in the Owner Manual.
• Verify the ECT has not shifted in value. Refer to Temperature Versus Resistance (ECT and IAT) .

Lack of Power, Hesitation, or Cut Out

• Inspect the engine electrical system for correct operation. Refer to Symptoms - Engine Electrical .
• Compare the vehicle with a similar unit. Ensure the vehicle has an actual problem.
• Inspect for a proper transmission operation.
• Inspect the engine oil level and quality.
• Inspect for an air leak in the charge air cooler.
• Inspect for a worn or damaged turbo charger turbine wheel, shaft or compressor wheel.
• Inspect for a restricted or plugged exhaust.
• Inspect for a restriction in the charge air cooler.
• Inspect for a skewed mass air flow (MAF) sensor.
• Inspect that the exhaust gas recirculation (EGR) valve is fully closing.
• Ensure that the EGR valve does not bind when manually moving the valve.
• Inspect the torque converter clutch (TCC) operation.
• Inspect the air conditioning system for the correct operation.

Rough, Unstable, or Incorrect Idle and Stalling

• Inspect the engine mounts.
• Inspect the intake and exhaust manifolds for casting flash.
• The exhaust system for damaged or collapsed pipes
• The exhaust manifold for a collapsed inner wall
• The mufflers for heat distress or possible internal failure
• Inspect the park neutral position (PNP) switch circuit.

Surges/Chuggles

• Ensure the driver understands the torque converter clutch (TCC) operation.
• Ensure the driver understands the A/C compressor operation.
• Use the scan tool to ensure the vehicle speed sensor (VSS) reading matches the speedometer.

Fuel Knock/Combustion Noise

• Inspect for obvious overheating problems. Refer to Engine Overheating .
• Inspect for a low engine coolant level.
• Inspect for any restricted air flow through the radiator.
• Inspect for a malfunctioning or incorrect thermostat.
• Inspect for a correct coolant solution. The solution should be a 50/50 mix of anti-freeze and water.