Preliminary Checks

Most driveability problems in the engine control system result from faulty or poor wiring, or loose and/or leaking hose connections. To avoid unnecessary component testing, a visual check should be performed before beginning troubleshooting procedures to help spot these common faults. A preliminary visual check should include the following:

• Verify that battery terminals are clean and that battery is fully charged.
• Verify that vacuum connections on rear of throttle body are secure and not leaking.
• Check that all vacuum connections to purge solenoid are secure and not leaking.
• Check hoses to vapor canister.
• Verify that PCV valve is securely attached to intake manifold vacuum port and orifice plug is in valve cover nipple.
• Check that alternator wiring and belt are secure.
• Check vacuum line to MAP sensor.
• Check fuel lines to fuel pump. Verify that wiring is secure and not damaged.
• Verify that heated air door vacuum connections are secure and not leaking.
• Check hoses to back pressure transducer.
• Check power brake and speed control vacuum hoses.
• Verify that all connectors to SMEC are fully inserted into sockets. Check all other connectors to various sensors and switches.