Hard to Start

DEFINITION
Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

PRELIMINARY CHECKS
- Perform the careful visual / physical checks as described in Preliminary Checks.
- Make sure the driver is using the correct starting procedure.

SENSORS
- Check the Engine Coolant Temperature (ECT) sensor using a Tech 1, compare engine coolant temperature with Intake Air Temperature (IAT) on cold engine.
- If engine coolant temperature readings are 5 degrees greater than or less than intake air temperature on a cold engine, check resistance in engine coolant sensor circuit or sensor itself. Compare ECT sensor resistance value to the DTC 15 chart, refer to Procedures / Diagnostic Charts / Code 15 Coolant Sensor Circuit. Testing and Inspection

- Check the Throttle Position (TP) sensor for binding or a high TP sensor voltage with the throttle closed. Scan tool and/or voltmeter should display less than 0.85 volt and 0% throttle angle (throttle closed).

FUEL SYSTEM
- Check the fuel pump relay operation - pump should turn "ON" for 2 seconds when ignition is turned "ON", refer to Procedures / Diagnostic Charts / Chart A-5 Fuel Pump and Relay Electrical Test. Testing and Inspection
- Check Fuel pressure, refer to Procedures / Diagnostic Charts / Chart A-6 Fuel System Diagnosis. Testing and Inspection
- Check For contaminated fuel and sufficient fuel quantity.
- Check the fuel pump relay - Connect test light between fuel pump "test" terminal and ground. Test light should be "ON". If not, refer to Procedures / Diagnostic Charts / Chart A-5 Fuel Pump and Relay Electrical Test. Testing and Inspection

IGNITION SYSTEM
- Check for proper ignition voltage output with spark tester J 26792 (ST 123) or equivalent.
- Check spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. Repair or replace as necessary.
- Check bare or shorted wires.
- Check for moisture in the distributor cap and for a worn shaft.
- Check the pickup coil resistance and connections
- Check for loose ignition coil connections.
- Check circuit 423 (ignition control) for short to ground.

ADDITIONAL CHECKS
- Check Idle air Control (IAC) valve operation, refer to Procedures / Diagnostic Charts / Code 35 Idle Air Control (IAC) System. Testing and Inspection
- Check Exhaust Gas Recirculation (EGR) operation, refer to Procedures / Diagnostic Charts / C Charts / EGR System Check. Testing and Inspection
- Check Service Bulletins for PROM updates.