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

^ Refer to Important Preliminary Checks and Visual and Physical Checks Before Starting.

^ Check PCM grounds for being clean, tight and in their proper locations. Refer to Diagrams / Powertrain Control Module for PCM ground numbers and locations.

^ Search for Technical Service Bulletins.

SENSOR/SYSTEM

^ Check Engine Coolant Temperature (ECT) sensor for being shifted in value. Connect a Scan Tool and compare Engine Coolant Temperature with Intake Air Temperature (IAT) on a cold engine. The ECT and IAT should be within 13°C (5°F) of each other. Check the resistance of the ECT sensor if the temperature is out of range with the IAT sensor. Refer to Specifications / Temperature vs Resistance for resistance specifications. Replace ECT sensor if the resistance is not within the specification. If the sensor is within the specification, repair ECT signal circuit for high resistance.

^ Check Mass Air Flow (MAF) sensor installation. A MAF sensor that is installed in the wrong direction, may cause a hard start. Embossed arrows on the MAF sensor indicate air flow and must point toward the engine. Install MAF in the proper direction. Refer to Mass Air Flow Sensor / Service and Repair.

^ Using a Scan Tool, monitor Throttle Position (TP) sensor voltage. The TP sensor voltage should be less then 0.9 volt. If the TP sensor voltage is greater than 0.9 volt, inspect the Acceleration Slip Regulation (ASR)/Traction Control System (TCS) adjuster assembly (If so equipped). Also inspect throttle body and accelerator cables for binding. Refer to Adjuster Assembly Throttle And Cruise Control Cables.

FUEL

^ Check fuel pump relay operation; pump should turn ON for 2 seconds when ignition is turned ON. Refer to Fuel Pump Relay Circuit Diagnosis.

^ 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, refer to Fuel System Diagnosis.

^ Check both injector fuses for being open. An open injector fuse will cause four injectors not to operate. Replace fuse and inspect injector circuits for an intermittent short to ground.

^ Check for low fuel pressure. Refer to Fuel System Diagnosis.

^ Check for restricted fuel filter. Refer to Fuel System Diagnosis.

^ Check for contaminated fuel. Refer to Alcohol/Contaminants-In-Fuel Test.

IGNITION SYSTEM

^ Check for proper ignition voltage output with spark tester J 26792. Refer to Distributor Ignition System Check.

^ Remove spark plugs and check for the following:

- Wet plugs

- Cracks

- Wear

- Improper gap

- Burned electrodes

- Heavy deposits

^ Refer to Spark Plug / Service and Repair / Replacement.

If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

^ Check for bare or shorted ignition wires. Refer to Spark Plug Wire / Service and Repair.

^ Check for loose ignition coil ground. Refer to Distributor Ignition System Check.

^ Spark plugs for proper heat range. Refer to Spark Plugs / Application and ID.

^ Check distributor vent system for being restricted or open. Refer to Distributor Vent System Check.

ENGINE MECHANICAL

^ Excessive oil in combustion chamber-Leaking valve seals. Refer to Engine / System Diagnosis.

^ Low cylinder compression. Refer to Engine / System Diagnosis.

^ Combustion chambers for excessive carbon buildup. Clean using Top Engine Cleaner. Follow instructions on can.

^ For incorrect basic engine parts. Inspect the following:

- Cylinder heads

- Camshaft

- Pistons, etc.

Refer to Engine.

ADDITIONAL CHECKS

Using a scan tool, check Idle Air Control (IAC) operation.