Checks
| Action
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DEFINITION: The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.
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Preliminary Checks
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| • | Compare the customer's vehicle with a similar unit in order to determine if the customer has an actual problem. |
| • | Remove the air filter element and check for dirt or restrictions. |
| • | Check the air inlet duct for any blockage or restrictions. |
| • | Check the transmission shift pattern and down shift operation. |
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Fuel System Checks
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| • | Check for a restricted fuel filter or incorrect fuel pressure |
| • | Check for contaminated fuel. |
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Ignition System Checks
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| • | Check for the proper ignition voltage output with a
J 26792 or an equivalent. |
| • | Check for the correct firing order (routing) of the ignition wires. |
| • | Check the knock sensor and the sensor's circuit shielding. The knock sensor is not diagnosed for excessive activity. A faulty knock sensor or signal interference could cause excessive retard of the ignition timing advance. Observe the Spark parameter
on a scan tool and compare with a known good vehicle. A typical value with the transmission in OD at 65 mph is 26-32 degrees. |
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Exhaust System Checks
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| • | Check the exhaust system for a possible restriction. Refer to Restricted Exhaust System Check . |
| • | Inspect the exhaust system for damaged or collapsed pipes. Inspect the muffler for heat distress or a possible internal failure. |
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Engine Mechanical Check
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| • | Check for any of the following engine mechanical problems: |
| - | Incorrect or worn camshaft |
| • | Refer to Engine Mechanical. |
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Additional Checks
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| • | Check the PCM grounds for being clean, tight, and in their proper locations. Refer to PCM Wiring Diagrams. |
| • | Check the generator output voltage. |
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