Lack of Power, Sluggish or Spongy
Checks
| Action
|
DEFINITION: Engine
delivers less than expected power. Little or no increase in speed when
the accelerator pedal is pushed down part way.
|
Preliminary Checks
|
|
Fuel System Checks
|
| • | Inspect items which can cause an engine to run rich (long term
fuel trim is significantly in the negative range). Refer to Diagnostic Aids
in
DTC P0172 Fuel Trim System Rich
. |
| • | Inspect items that can cause an engine to run lean (long term
fuel trim is significantly in the positive range). Refer to Diagnostic Aids
in
DTC P0171 Fuel Trim System Lean
. |
|
Sensor/System
|
| • | If the knock retard is above 10-12 degrees, disconnect
the KS, and ground the sensor harness connector. Monitor knock retard
on the scan tool, there should be no knock retard present, if knock
retard is still present, replace the PCM. Refer to
Powertrain Control Module Replacement/Programming
. |
| • | Inspect for a restricted air intake system. |
|
Ignition System
|
| • | Inspect for proper ignition voltage output using the following
steps: |
| - | Clip the J 26792
spark tester to engine ground. |
| - | Connect one end of a spark plug wire to the J 26792
spark tester. Leave the other end of
the spark plug wire to the coil being tested. |
| - | Connect one end of another spark plug wire to the other coil
tower. Connect the other end of the spark plug wire to ground. |
| - | Crank the engine while observing the J 26792
spark tester. A spark should be observed. |
| - | Repeat the above steps for each coil. |
| • | If spark is not present at the plugs, inspect for the following
conditions: |
| - | Inspect the coils for cracks, carbon tracking/arcing, or a resistance
value outside the specified range. |
Coil Resistance
5K-7K ohms (5,000-7,000 ohms ) | - | Inspect the spark plug wires for 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
1 968 ohms per meter (600 ohms per foot ).
| | Important: : Spraying the secondary ignition wires with a light mist of water may
help locate an intermittent problem. Ignition components will arc to ground
when a secondary component is faulty.
|
| - | Ignition System Wiring--Loose ignition module feed or ground
connection, or damaged system wiring |
| • | Remove the spark plugs and inspect for the following: |
| - | 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. |
|
Engine Mechanical
|
| • | For incorrect basic engine parts--Inspect the following: |
|
Additional Checks
| Check the exhaust system for possible restrictions. Inspect
for the following:
| • | Inspect the exhaust system for damaged or collapsed pipes. |
| • | Inspect the mufflers for heat distress or possible internal failure. |
|
