Inspection/Test
| Action
|
DEFINITION: Fuel economy, as measured by an
actual road test is noticeably lower than expected. Also, economy is
noticeably lower than on this vehicle at one time, as previously
shown by an actual road test.
|
Preliminary
|
| • | Verify the driving habits of the owners by asking the following
questions: |
| - | Is the A/C ON full time (Defroster mode ON)? |
| - | Are tires at correct pressure? |
| - | Are excessively heavy loads being carried? |
| - | Is acceleration too much, too often? |
|
Fuel System
|
| • | Ensure each injector harness is connected to the correct injector/cylinder. |
| • | Inspect for fuel in the pressure regulator vacuum hose. |
|
Sensor/System
|
| • | Monitor the 24X crankshaft position and camshaft position sensors
on scan tool. If both are not responding, inspect the sensor feed circuits. |
| • | Inspect air intake system and crankcase for air leaks. |
| • | Inspect for proper calibration of speedometer. Connect J 33431-B
signal generator to
VSS electrical connector. Ignition on, tester on and monitor the
speedometer. |
|
Ignition System
|
| • | Inspect for proper ignition voltage output using the following
steps: |
| 1. | Attach the J 26792
spark tester to engine ground. |
| 2. | Connect the spark plug end of the spark plug wire to the J 26792
spark tester; leave the
other end of the spark plug wire connected to the coil being tested. |
| 3. | Connect the spark plug end of the companion spark plug wire to
ground. |
The companion spark plug wire is the wire attached to the corresponding
coil tower.
| 4. | Crank the engine while observing the J 26792
spark tester; a spark should be observed. |
| 5. | Repeat the above steps for each coil. |
| • | If spark is not present at the coils, inspect for the following
conditions: |
| - | Coils--Cracks, carbon tracking/arcing, or a resistance value
outside the specified range. |
Coil Resistance
5000-8000ohms (5K-8Kohms) | - | Spark Plug wires--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
600ohms per foot (1 968ohms per meter).
| | Important: : Spraying the secondary ignition wires with a light mist of water may
help locate an intermittent problem. Ignition voltage will arc to ground when
a secondary component is faulty.
|
| - | Defective ignition module. |
| - | Ignition system wiring--Loose ignition module feed or ground
connection, or damaged system wiring. |
| • | Remove spark plugs and inspect for the following conditions: |
| - | 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. |
| • | If spark plugs are gas or oil fouled, the cause of the fouling
must be determined before replacing the spark plugs. |
|
Engine Cooling System
|
| • | Inspect the engine coolant level. |
|
Engine Mechanical
|
| • | Inspect the engine mechanical for the following: |
| - | Sticking or leaking valves |
| - | Excessive oil in combustion chamber-Leaking valve seals |
| • | Inspect for the following incorrect basic engine parts : |
|
Additional
|
| • | Test the torque converter clutch (TCC) operation. Refer to diagnostic
aids for the TCC in Transaxle Diagnosis. |
| • | Inspect the exhaust system for possible restriction. Inspect
the following areas: |
| - | The exhaust system for damaged or collapsed pipes |
| - | The mufflers for heat distress or possible internal failure |
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