TEST ACTION APPLICABILITY
6 Turn the ignition off.
Connect a Vacuum Gauge to a Manifold Vacuum source.
Start the engine.
Allow the engine to idle.
Note: If engine will not idle, maintain a constant RPM above idle.
With the DRBIIIt in Sensors, read the MAP Sensor vacuum value.
Is the DRBIIIt reading within 19 of the Vacuum Gauge reading?
All
Yes → Go To 7
No → Replace the MAP Sensor.
Perform POWERTRAIN VERIFICATION TEST VER-5-NGC.
7 Note: For this test to be valid, the thermostat must be operating correctly.
Note: This test works best if performed on a cold engine (cold soak)
Ignition on, engine not running.
With the DRBIIIt, read the Engine Coolant Temperature (ECT) Sensor value. If the
engine was allowed to sit overnight (cold soak), the temperature value should be a
sensible value that is somewhere close to the ambient temperature.
Note: If engine coolant temperature is above 82°C (180°F), allow the engine
to cool until 65°C (150°F) is reached.
Start the Engine.
During engine warm-up, monitor the ECT Sensor value. The temperature value
change should be a smooth transition from start up to normal operating temperature
82°C (180°F). The value should reach at least 82°C (180°F).
Did the ECT value increase with a smooth transition and did it reach at least 82°C?
All
Yes → Go To 8
No → Replace the Engine Coolant Temperature Sensor.
Perform POWERTRAIN VERIFICATION TEST VER-5-NGC.
8 Check for any of the following conditions/mechanical problems.
AIR INDUCTION SYSTEM - must be free from leaks.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
correct injector
Are there any engine mechanical problems?
All
Yes → Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER-5-NGC.
No → Test Complete.
105
DRIVEABILITY - NGC
P0171-FUEL SYSTEM 1/1 LEAN — Continued
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