Checks
| Action
|
DEFINITION: The engine delivers less than expected power. There is little
or no increase in speed when partially applying the accelerator pedal.
|
Preliminary
Checks
|
| • | Compare the customer's vehicle with a similar vehicle in order
to determine the severity of the customer's concern. |
| • | Remove the air filter element and check for dirt or restrictions. |
| • | Check the transmission shift pattern and down shift operation. |
|
Fuel System Checks
|
| • | Check for a restriction in the fuel supply system. Check for the
correct fuel pressure. Refer to
Fuel System Diagnosis
. |
|
Ignition System Checks
|
| • | Check for adequate secondary ignition voltage with a J 26792
spark tester or an equivalent. |
| • | Check for the proper operation of the ignition control system. |
| • | Check the CKP sensor engine reference signal with a scan tool.
Observe the Engine Speed parameter while operating the engine at the speed
of the concern. The scan tool should indicate steady and linear RPM readings
while running. If the erratic values, such as sudden spikes or drops in engine
speed are displayed, the engine reference signal is not stable enough for
the engine to run properly. Check for a short to ground in the CKP sensor
Ignition Reference Low circuit . A short to ground in the CKP sensor Ignition
Reference Low circuit will cause a faulty engine reference signal to be sent
to the PCM, but will not set a CKP sensor DTC (P0335). |
|
Exhaust System Checks
|
| • | Inspect the exhaust system for damaged or collapsed pipes. Inspect
the muffler for heat distress or a possible internal failure. |
|
Additional Checks
|
| • | Check the PCM grounds for being clean, tight, and in their proper
locations. Refer to PCM Wiring Diagrams. |
| • | Check the generator output voltage. |
|
Engine Mechanical Check
| Check for any of the following engine mechanical problems:
| • | Incorrect or worn camshaft |
Refer to Engine Mechanical.
|
