Inspection/Test
| Action
|
DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually
run, or may start but immediately stalls.
|
Preliminary
|
|
Sensor/System
|
| • | Test engine coolant temperature (ECT) sensor for being shifted in value.
Connect a scan tool and compare ECT with intake air temperature (IAT) on a cold
engine. The ECT and IAT should be within ± 3°C (5°F) of each other.
Test the resistance of the ECT sensor if the temperature is out of range with the
IAT sensor. Refer to
Temperature Versus Resistance
.
If the ECT sensor resistance is not within the specification, refer to
DTC P0117
or
DTC P0113
. |
| • | Monitor the 24X crank sensor and the CMP sensor signal present
parameters on a scan tool. If both are not responding, test the sensor feed
circuit. Both sensors use a separate feed circuit but are internally connected
to power. Test all CKP sensor A and CMP sensor circuits for intermittents.
Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. |
| • | Monitor the 3X crank sensor parameter on the scan tool. If the 3X crank
sensor parameter is not responding, inspect the CKP sensor and circuits for intermittents.
Inspect the ignition control (IC) circuit, IC timing control circuit, low resolution
engine speed signal circuit and the low reference circuit for intermittents. If these
circuits become open, or shorted, they may not set a DTC immediately, but are capable
of causing driveability complaints. Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. |
| • | Inspect the mass air flow (MAF) sensor for proper installation and conditions.
A MAF sensor with a damaged honeycomb may cause a hard start. |
| | Inspect
the air intake ducts for being collapsed, damaged areas, looseness, improper installation,
or leaking, especially between the MAF sensor and the throttle body. |
| • | Using a scan tool, test the idle air control (IAC) operation. Command
the engine RPM to 1,500 RPM and back to the starting RPM. |
| | If the
engine RPM does not change when commanded refer to
DTC P0506
and
DTC P0507
to diagnose
the IAC system. |
|
Fuel System
|
|
Ignition System
|
| • | Inspect for proper ignition voltage output using the following steps: |
| 1. | Attach the J 26792
Spark
Tester to engine ground. |
| 2. | Connect the spark plug end of the spark plug wire to the J 26792
. Connect the other end of the spark plug wire
to the coil being tested. |
| 3. | Connect the spark plug end of the companion spark plug wire to ground.
The companion spark plug wire is the wire attached to the corresponding coil tower. |
| 4. | Crank the engine while observing the J 26792
. A spark should be observed. |
| 5. | Repeat the above steps for each coil. |
| • | If spark is not present at the coils, inspect for the following conditions: |
| - | Coils--Cracks, carbon tracking/arcing, or a resistance value outside
the specified range. |
Coil Resistance
5,000-8,000ohms | - | Spark Plug wires--signs of arcing, cross firing, cracks, carbon
tracking, plug boot damage, pinched, improper routing, or a resistance
value outside the specified range. |
Spark Plug Wire Resistance
9,868 ohms per meter (3,000 ohms per foot)
| | Important: : Spraying the secondary ignition wires with a light mist of water may help locate
an intermittent condition. Ignition voltage arcs to ground when a secondary component
is faulty.
|
| - | Defective ignition module |
| - | Ignition system wiring--Loose ignition module feed or ground connection,
or damaged system wiring. |
| • | Remove spark plugs and inspect for the following conditions: |
| - | Burned or damaged electrodes |
| - | Improper heat range or reach |
| • | If spark plugs are gas or oil fouled, the cause of the fouling must be
determined before replacing the spark plugs. Refer to
Spark Plug Inspection
. |
|
Engine Mechanical
|
| • | Inspect for incorrect engine parts, such as the following basic components: |
| - | The camshaft and valve train components |
|
