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
|
• | Search for service bulletins. |
• | Check and compare the customers vehicle to a similar vehicle.
Make sure the customers vehicle has an actual problem. |
• | Check the air cleaner filter for dirt or being plugged. |
|
Fuel System Checks
|
• | Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis
. |
• | Check items which can cause an engine to run rich (long term fuel
trim is significantly in the negative range). Refer to Diagnostic Aids
for
DTC P0172 Fuel Trim System Rich
. |
• | Check items that can cause an engine to run lean (long term fuel
trim is significantly in the positive range). Refer to Diagnostic Aids
for
DTC P0171 Fuel Trim System Lean
. |
• | Check the throttle linkage and throttle cables to ensure the throttle
plate opens fully. |
|
Sensor/System
|
• | Using a scan tool, monitor KS system for excessive spark retard
activity. |
• | Check for proper operation of the TP sensor. |
• | Check the EGR system for proper operation. |
• | Check for proper operation of the O2S 1 sensor. |
• | Check for a restricted air intake system. |
|
Ignition System
|
• | Check for proper ignition voltage output with the J 36012-A
spark plug jumper wires and J 26792
spark tester or equivalent. |
• | Check the spark plugs for the following conditions: |
- | Check for wet or fuel fouled spark plugs. |
- | Check for cracks on the spark plugs. |
- | Check for improper spark plug gap. |
- | Check for burned 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. |
• | Check the Ignition Control Module (ICM) for proper ground connection. |
• | Check the ignition coils for cracks or carbon tracking. |
|
Engine Mechanical
|
• | Check the engine for the following engine mechanical problems: |
- | Check for correct valve timing. |
- | Check for leaking cylinder head gasket. |
- | Check for a worn or a incorrect camshaft. |
• | Refer to the Engine Mechanical. |
|
Additional Checks
|
• | Check for proper operation of the transaxle and the TCC. Refer
to
Road Test
in Automatic Transaxle. |
• | Check the exhaust system for a possible restriction: |
- | Inspect the exhaust system for damaged or for possible collapsed
pipes. |
- | Inspect the muffler for heat distress or for possible internal
failure. |
• | Check the vacuum lines for kinks or leaks. |
• | Check the generator output voltage. Repair the generator if the
output voltage is less than 11 volts or more than 16 volts. |
• | Check the A/C system operation. The A/C clutch should cut out
at the Wide Open Throttle (WOT) position. |
• | If all procedures have been completed and no malfunctions have
not been found, review and inspect the following items: |
- | Visually and physically inspect all electrical connections within
the suspected circuit and/or systems. |
|