Checks
| Action
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DEFINITION: Momentary lack of response as the accelerator
is pushed down. Can occur at any vehicle speed. Usually more pronounced
when first trying to make the vehicle move, as from a stop sign.
May cause the engine to stall if severe enough.
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Preliminary
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| • | Search for service bulletins. |
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Sensor/System
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| • | The O2S 1 should respond quickly to different throttle
positions. If not, check the O2S 1 for silicon or other
contaminants from fuel or the use of improper RTV sealant. The sensors
may have a white powdery coating. Silicon contamination causes
a high but false O2S 1 signal voltage (rich exhaust indication).
The PCM will reduce the amount of fuel delivered to the engine,
causing a severe driveability problem. Refer to oxygen sensor
in
Information Sensors/Switches Description
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| • | Test for proper operation of the following sensors: |
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Fuel System
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| • | Inspect for a restricted fuel filter. |
| • | Inspect items which can cause an engine to run rich (Long Term
FT is significantly in the negative range). Refer to Diagnostic Aids for
DTC P0172 Fuel Trim System Rich
. |
| • | Inspect items that can cause an engine to run lean (Long Term
FT is significantly in the positive range). Refer to Diagnostic Aids for
DTC P0171 Fuel Trim System Lean
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| • | Test for proper operation of the evaporative emission (EVAP)
control system. |
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Ignition System
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| • | Test for proper ignition voltage output with a J 26792
Spark Tester or equivalent. |
| • | Inspect the spark plugs for the following conditions: |
| - | Burnt electrodes or heavy deposits |
| • | If the spark plugs are fuel or oil fouled, the cause of the fouling
must be determined before replacing the spark plugs. |
| • | Inspect the ignition control module (ICM) for proper ground connection. |
| • | Inspect the ignition coils for cracks or carbon tracking. |
| • | Test/inspect the spark plug wires for proper resistance and condition. |
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Additional Checks
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| • | Test the generator output voltage. Repair the generator if the
output voltage is less than 11 volts or more than 16 volts. |
| • | If all procedures have been completed and no malfunctions have
been found, review and inspect the following items: |
| - | Visually and physically inspect all electrical connections within
the suspected circuit and systems. |
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