Hard Start
Checks
| Action
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DEFINITION: The engine cranks OK, but does not start for a long time.
The engine does eventually run, or may start but immediately dies.
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Preliminary Checks
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| • | Make sure the driver is using the correct starting procedure. |
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Sensor Checks
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| • | Check the Engine Coolant Temperature (ECT) sensor using a scan
tool to compare the engine coolant temperature with the ambient air temperature
on a cold engine. If the coolant temperature reading is more than 5°C
(41°F) greater or less than the ambient air temperature on a cold engine,
check for a high resistance in the coolant sensor circuit or the sensor
itself. Refer to
Temperature Versus Resistance
. |
| • | Check the Throttle Position (TP) sensor. A sticking throttle shaft
or a binding throttle linkage will causes a high TP sensor voltage (open throttle
indication). Under these conditions the PCM may not control the idle. Monitor
the TP sensor angle with the scan tool. The indicated angle should be aproximately
11% with throttle closed. |
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Fuel System Checks
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| • | Check for no Crank signal to the PCM (C3-11) if the vehicle is
slower to start in cold weather. Observe the Starter Switch parameter on a
scan tool while cranking the engine. The PCM provides slightly more fuel
for engine start up when receiving the Crank input. |
| • | Check the fuel pump check valve. A faulty in-tank fuel pump check
valve will allow the fuel in the lines to drain back to the tank after stopping
the engine. This condition is especially troublesome on hot soak restarts.
In order to check for this condition perform the following steps: |
| 1. | Turn OFF the ignition. |
| 2. | Disconnect the fuel line at the fuel filter |
| 3. | Remove the fuel tank filler cap. |
| 4. | Connect a radiator test pump to the fuel line and apply 102 kPa
(15 psi) of pressure. The check valve is OK if the pressure holds for
60 seconds. |
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Ignition System Checks
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| • | Check for the proper secondary voltage output with a spark tester
(J 26792 or equivalent). |
| • | Check the spark plugs for any of the following conditions: |
| - | Wet (fuel fouled) plugs. |
| - | A terminal screw that is bent or loose (rotate and pull). |
| - | A ceramic insulator that has cracks, carbon tracking or deposits
(red or black dust) |
| - | A tip insulator that has cracks, carbon tracking, deposits (oil,
carbon, glazing, fuel additive), or is loose (rattles). |
| - | A center electrode that is loose (wiggles side to side) |
| - | An incorrect spark plug gap that is too large or too small. |
| - | Platinum pads that are missing. |
| • | Check for bare or shorted ignition wires. |
| • | Check for loose ignition coil connections. |
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Additional Checks
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| • | Check the IAC system for proper operation. |
| • | Check for no crank signal. |
| • | Check the Service Bulletins for any updates. |
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