Engine Is Difficult to Start

ENGINE IS DIFFICULT TO START

Conditions
^ No DTCs.
^ Engine is hot.

Fault Sources
^ Contact resistance in Engine Speed (RPM) Sensor connector.
^ Defective RPM sensor.
^ Contact resistance in Camshaft Position (CMP) Sensor connector.
^ Contact resistance in Engine Coolant Temperature (ECT) Sensor connector.
^ Defective ECT sensor.
^ Defective/damage spark plugs/ignition leads.
^ Defective distributor cap/rotor.
^ Faulty fuel or residual pressure.
^ Contact resistance in power stage connector.

TESTING PROCEDURE





Cleaning and Greasing of ECM Connector
^ Switch Ignition OFF.
^ Wait for approx. 150 seconds.
^ Remove ECM.
^ Rectify the ECM's connector with regard to contact resistance and oxidation.
^ Reinstall the ECM.
^ When the connector is rectified: Clean and grease the ECT sensor's connector.

Cleaning and Greasing of ECT Sensor Connector
^ Switch Ignition OFF.
^ Disconnect the ECT sensor.
^ Rectify the ECT sensor's connector with regard to contact resistance and oxidation.
^ Connect the ECT sensor.
^ When the connector is rectified: Check the engine coolant temperature.





Checking the Engine Coolant Temperature
^ Ignition ON.
^ Check that the ECT reading is reasonable.

Engine coolant temperature should be above 80°C (176°F) with a hot engine, the upper radiator hose should be hot.

If the reading is OK:
- Clean and grease the CMP sensor's connector.
If the reading is incorrect:
- Test with a new ECT sensor.
- Then continue with: Cleaning and greasing of the CMP sensor's connector.





Cleaning and Greasing of the CMP Sensor's Connector
^ Ignition OFF.
^ Disconnect the CMP sensor.
^ Rectify the CMP sensor's connector with regard to contact resistance and oxidation.
^ Connect the CMP sensor.
^ When the connector is rectified: Check the RPM sensor.





Checking the RPM Sensor
^ Ignition OFF.
^ Disconnect the RPM sensor.
^ Connect an ohmmeter between the RPM sensor's connector 1 and 2.

The ohmmeter should show 200 - 500 Ohms depending on the engine coolant temperature.

If the reading is OK:
- Clean and grease the RPM sensor's connector.
If the reading is incorrect:
- Test with a new RPM sensor.
- Then continue with: Cleaning and greasing of the RPM sensor's connector.





Cleaning and Greasing of the RPM Sensor's Connector
^ Ignition OFF.
^ RPM sensor disconnected.
^ Rectify the RPM sensor's connector with regard to contact resistance and oxidation.
^ Connect the RPM sensor.
^ When the connector is rectified: Check the ignition coil's primary winding.





Checking the Ignition Coil's Primary Winding
^ Ignition OFF.
^ Undo one of the terminal connectors from the ignition coil.
^ Connect an ohmmeter between the primary winding's two connectors (1 and 15).

The ohmmeter should show 0.5 - 1.5 Ohms at +20°C (68°F).

If the reading is OK:
- Check the ignition coil's secondary winding.
If the reading is incorrect:
- Test with a new ignition coil.
- Then continue with: Cleaning and greasing of the power stage connector.





Checking the Ignition Coil's Secondary Winding
^ Ignition OFF.
^ Disconnect the ignition coil's high-tension lead.
^ Connect an ohmmeter between connector 15 and the high-tension connector on the ignition coil.

The ohmmeter should show approx. 8 - 9K Ohms at +20°C (68°F).

If the reading is OK:
- Clean and grease the power stage connector.
If the reading is incorrect:
- Test with a new ignition coil.
- Then continue with: Cleaning and greasing of the power stage connector.





Cleaning and Greasing of the Power Stage Connector
^ Ignition OFF.
^ Rectify the power stage connector with regard to contact resistance and oxidation.
^ Connect the power stage.
^ When the connector is rectified: Check the distributor cap, rotor and ignition leads.





Checking the Distributor Cap, Rotor and Ignition Leads
^ Ignition OFF.
^ Check the distributor cap, rotor and ignition leads for signs of damage, cracks and flashover.

If a fault is suspected:
- Clean or if necessary replace components which may be damaged or faulty.
- Reinstall the distributor cap and rotor.
- Then continue with: Spark plugs.





Spark Plugs
^ Ignition OFF.
^ Replace all spark plugs.

NOTE: It is vital that the correct spark plugs are fitted, see the parts catalogue for the P/N. Check also the spark gap of the new spark plugs before fitting them. The gap should be 0.7 - 0.8 mm.

^ Reattach all ignition leads.
^ Then continue checking the fuel and residual pressure.