Inspections
| Action
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DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.
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Preliminary
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| • | Inspect the engine control system grounds for being clean, tight, and in the correct locations. Refer to
Engine Controls Schematics
. Ensure the resistance between the engine control module (ECM) housing and
the battery negative cable is less than 0.5 ohms. |
| • | Verify that the ECM and ECM bracket fasteners are at the correct torque. |
| • | Search for service bulletins that may address this condition. |
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Sensor/System
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| | Important: Allow the engine to cool before performing this test.
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| • | Inspect the engine coolant temperature (ECT) sensor for being skewed in value. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F).
If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to
Temperature Versus Resistance - Engine Coolant Temperature Sensor
for resistance specifications. Replace the ECT sensor
if the resistance is not within the specification. Refer to
Engine Coolant Temperature Sensor Replacement
. If the sensor is within the specification, repair the high resistance in the ECT signal circuit. |
| • | Inspect the crankshaft position (CKP) sensor for the correct resistance. The sensor resistance may be out of range after a hot soak. Measure that the resistance remains within 700-1,200 ohms at all temperatures. |
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Fuel System
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Ignition System
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| • | Inspect for the correct installation of the ignition coil seals. Incorrect installation may allow water to enter the spark plug area. Inspect for moisture and corrosion. |
| • | Remove the spark plugs and inspect for the following conditions: |
| - | Refer to the following procedures: |
| • | If the spark plugs are gas, coolant or oil fouled, determine the cause before replacing the spark plugs. Refer to the following procedures: |
| - | For diagnosis of coolant contaminated spark plugs, refer to
Loss of Coolant
. |
| • | Inspect the spark plug boots and terminals for burning or micro-arcing, corrosion, and damage to the insulation. |
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Engine Mechanical
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| • | Inspect for the following engine mechanical conditions: |
| - | Excessive oil in combustion chamber or leaking valve seals |
| - | Low cylinder compression |
| - | Sticking or leaking valves |
| - | Excessive carbon buildup in the combustion chambers. Clean the chambers with top engine cleaner. Follow the instructions on the can. |
| - | For more information, refer to the following procedures: |
| • | Inspect the following components for incorrect basic engine parts: |
| - | Pistons, connecting rods, or bearings. |
| - | Refer to the following procedures: |
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