Engine Cranks But Does Not Run

Circuit Description
Battery voltage is applied to the ignition coil when the ignition switch is turned to the ON or START positions. The ignition control module toggles the primary windings of the ignition coil in order to induce a high voltage in the secondary windings of the ignition coil. The powertrain control module (PCM) commands the ignition control module based on numerous inputs including the camshaft position sensor. The high voltage induced in the secondary windings of the ignition coil is applied through the distributor cap and rotor to the spark plugs.

Diagnostic Aids
Check for any of the following conditions:
^ The fuel injectors may spray fuel, but not enough fuel to start the engine. Check the engine coolant temperature (ECT) sensor reading with a scan tool. The indicated temperature should be close to the actual engine temperature in order for the PCM to deliver the correct amount of fuel.
^ Check TP sensor reading with a scan tool. The TP sensor reading should be 7-18% (0.42-1.15 volts) with the throttle closed.
^ Check the battery condition and the engine cranking speed. The engine will not start and improper diagnosis may occur if the starting system is not operating to necessary levels.
^ Water or foreign material can cause a no start during freezing weather. The engine may start after 5 or 6 minutes in a heated shop. The malfunction may not recur until parked overnight in freezing temperatures.
^ Low fuel pressure can result in a very lean air/fuel mixture which may be difficult to ignite. Observe the fuel discharge from the fuel injector and check fuel pressure. Refer to Fuel System Diagnosis. Component Tests and General Diagnostics
^ Fouled or damaged spark plugs will cause an Engine Cranks But Will Not Run condition.
^ A vehicle that starts and runs after being brought to the shop for a Engine Cranks But Will Not Run complaint, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and wiring in order to check for an engine miss or stall.
^ Check for a malfunctioning main relay. A faulty main relay can cause no MIL and an engine that cranks but will not run. Refer to Main Relay Circuit Diagnosis. Component Tests and General Diagnostics
^ Check the fuel injector resistor for faulty electrical connections or high electrical resistance. Normal fuel injector resistor resistance is 1.9-2.8 ohms at 20°C (68°F).
^ Check for a faulty IG fuse.

An intermittent malfunction may be caused by a fault in the ignition system electrical circuit. Inspect the wiring harness and components for any of the following conditions:
^ Backed out terminals.
^ Improper mating of terminals.
^ Broken electrical connector locks.
^ Improperly formed or damaged terminals.
^ Faulty terminal to wiring connections.
^ Physical damage to the wiring harness.
^ Broken conductor inside the wire insulation.
^ Corrosion of electrical connections, splices, or terminals.

Test Description
The numbers below refer to the step numbers in the Diagnostic Table.
1. The Powertrain OBD System Check prompts the technician to complete some basic checks and stores the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
3. This step checks for spark at the spark plugs.
5. This step checks for faulty secondary ignition wires.
10. This step checks for proper resistance of the ignition coil.
16. The test lamp should flash from dim to bright, indicating a good reference pulse to the ignition control module (Igniter).
17. A test lamp that stayed ON or OFF in step 20 indicates an open or a short in the ignition control module (Igniter) trigger circuit.
19. This step checks for a faulty noise suppressor filter.
20. This step checks for a faulty noise suppressor filter.