|
|
5. MAP SENSOR OPERATION 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. Is the scan tool reading within 1 ( of the Vacuum Gauge reading? Yes >> Go To 6 No >> Replace the MAP Sensor. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 6. ECT SENSOR OPERATION 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) With a scan tool, read the Engine Coolant Temperature (ECT) Sensor value. If the engine was allowed to sit over- NOTE: If engine coolant temperature is above 82°C (180°F), allow the engine to cool until 65°C (150°F) is During engine warm-up, monitor the ECT Sensor value. The temperature value change should be a smooth tran- Did the ECT value increase smoothly and did it reach at least 180°F (82°C)? Yes >> Go To 7 No >> Replace the Engine Coolant Temperature Sensor. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) 7. ENGINE MECHANICAL PROBLEM Turn the ignition off. 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? Yes >> Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE) No >> Go To 11 9 - 186 ENGINE ELECTRICAL DIAGNOSTICS KJ |