Test NS-3A - Inspecting Mechanical System
NOTE:
For connector terminal identification, see CONNECTOR IDENTIFICATION
. For wiring diagram, see WIRING DIAGRAMS
at end of article.
- Turn ignition off. Check spark plug wires for proper firing order. If firing order is not correct, reconnect wires in correct firing order. Perform VERIFICATION TEST VER-1 . If firing order is correct, remove all spark plugs and inspect tips for fuel (flooding). Clean spark plugs as necessary. Reinstall spark plugs. Connect timing light to engine.
- Check ignition timing while cranking engine. If ignition timing is 0-25 degrees BTDC, go to step 3). If timing is not 0-25 degrees BTDC, replace engine controller. Perform VERIFICATION TEST VER-1 .
- Locate cylinder No. 1 on distributor cap and mark housing for reference. Position piston in cylinder No. 1 to Top Dead Center (TDC) of compression stroke. Remove distributor cap and check if rotor is pointing to mark on distributor housing. Reposition distributor housing into correct alignment, if necessary, and go to next step.
- Turn ignition off. Disconnect engine controller connector and MAP sensor connector. Using a DVOM, check resistance of Violet/White wire (Brown/Yellow wire on Wrangler) between MAP sensor and engine controller connectors.
- If resistance is 10 ohms or more, repair open Violet/White wire (Brown/Yellow wire on Wrangler). Perform VERIFICATION TEST VER-1 . If resistance is less than 10 ohms, check valve timing and engine compression. If valve timing and engine compression are okay, replace MAP sensor. Perform VERIFICATION TEST VER-1 . If valve timing and engine compression are not okay, repair engine as necessary. Perform VERIFICATION TEST VER-1 .