Checks
| Action
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DEFINITION: Fuel economy,
as measured by an actual road test is noticeably lower than expected. Also,
economy is noticeably lower than it was on this vehicle
at one time, as previously shown by an actual road test.
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Preliminary
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| • | Inspect owners driving habits. |
| - | 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? |
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Fuel System
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| • | Ensure each injector harness is connected to the correct injector/cylinder. |
| • | Inspect for fuel in the pressure regulator vacuum hose. |
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Sensor/System
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| • | Inspect for 24X Crankshaft position and Camshaft position sensors
on scan tool. If both are not responding, inspect the sensor feed circuit
(Both sensors use a common feed circuit). |
| • | 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. |
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Ignition System
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| • | Test for proper ignition voltage output using the following steps: |
| 1. | Clip the J 26792
spark tester to engine ground. |
| 2. | 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. |
| 3. | Connect one end of another spark plug wire to the other coil
tower, connect the other end of the spark plug wire to ground. |
| 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 adequate 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
5000-8000 ohms (5K-9K ohms). | - | 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
600 ohms per foot (1 968 ohms per meter).
| | 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.
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| - | Ignition System Wiring--Loose ignition module feed or ground
connection, or damaged system wiring. |
| • | Remove 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. |
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Engine Cooling System
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| • | Inspect for proper engine coolant level. |
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Engine Mechanical
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| • | Inspect engine mechanical for the following: |
| - | Sticking or leaking valves |
| - | Excessive oil in combustion chamber-leaking valve seals. |
| • | For incorrect basic engine parts. Inspect for the following: |
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Additional Inspections
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| • | Inspect exhaust system for possible restriction. Inspect for
the following: |
| - | Inspect exhaust system for damaged or collapsed pipes. |
| - | Inspect mufflers for heat distress or possible internal failure. |
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