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 visual and physical checks as described under Diagnosis By Symptom/Preliminary Checks. - Important Preliminary Checks

Make sure the driver is using the correct starting procedure.

SENSORS
Check: Engine Coolant Temperature (ECT) sensor using a scan tool, compare ECT with ambient temperature on a cold engine. If ECT reading is either 5 degrees greater or less than ambient air temperature on a cold engine, check resistance in engine coolant sensor circuit or sensor itself. Compare ECT resistance value to the chart in "Diagnostic Aids" located in Diagnostic Trouble Code (DTC) 15. Powertrain Controls - ECM/PCM

Check: Manifold Absolute Pressure (MAP) sensor, Refer to Chart C-1D MAP Output Check. Chart C-1D Manifold Absolute Pressure (MAP) Output Check

Check: Mass Air Flow (MAF) sensor installation. A MAF sensor that is installed backwards can cause a rich condition. A malfunctioning MAF sensor may cause a no start or hard start.

Check: Throttle Position (TP) sensor for binding or a high TP sensor voltage with the throttle closed. The TP sensor voltage should read between 0.3 and 0.9 volt at closed throttle.

FUEL SYSTEM
Check: Fuel pump relay operation. The pump should turn "ON" for 2 seconds when ignition is turned "ON." Refer to Chart A-5 Fuel Pump Relay Circuit Diagnosis. Chart A-5 Fuel Pump Relay Circuit Diagnosis

Check: Fuel pressure. Refer to Chart A-7 Fuel System Diagnosis. Related Tests, Information and Procedures

Check: Contaminated fuel.

Check: Both injector fuses (visual inspect).

NOTE: A faulty in-tank fuel pump check valve will allow the fuel in the lines to drain back to the tank after engine is stopped. To check for this condition, perform Chart A-7 Fuel System Diagnosis. Related Tests, Information and Procedures

IGNITION SYSTEM
Check: For proper ignition voltage output with spark tester J26792 (ST 125).

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 shortened ignition wires.

Check: Loose ignition coil ground.

Check: Coil fuse.

Check: Distributor vent system. Refer to Chart C-4C Distributor Vent System Check. Chart C-4C Distributor Vent System Check

ADDITIONAL CHECKS
Check: Idle Air Control (IAC) operation using Chart C-2C Idle Air Control (IAC) Valve Check. Chart C-2C Idle Air Control (IAC) System Check

Check: Basic engine problem.

Check: PROM calibration I.D. for most current and/or incorrect software. Refer to PROM - Programmable Read Only Memory for calibration information. PROM - Programmable Read Only Memory