Engine Cranks But Does Not Run. Pontiac Firefly (Canada) 1999

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 1999 🢒 Firefly (Canada) 🢒 Engine 🢒 Engine Controls - 1.3L 🢒 Engine Cranks But Does Not Run

Engine Controls Components
Cell 21: Ignition System
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The battery voltage is applied to the ignition coils when the ignition switch is turned to the ON position or to the START position. The circuitry within the ignition coil assemblies 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) controls the ignition event based on numerous inputs including the crankshaft position sensor. The high voltage that is induced in the secondary windings of the ignition coils is applied through the spark plug wires to the spark plugs.

Diagnostic Aids

Check for any of the following conditions:

•	Check the battery condition and the engine cranking speed. The engine will not start, and incorrect diagnosis may occur if the starting system is not operating at necessary levels. Refer to Starting System Check .

•	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 occur again until the vehicle is parked overnight in freezing temperatures.

•	Low fuel pressure can result in a very lean air/fuel mixture which may be difficult to ignite. Refer to Fuel System Diagnosis .

•	Fouled spark plugs or damaged spark plugs may cause an Engine Cranks But Will Not Run condition. Refer to Spark Plug Visual Diagnosis .

•	A vehicle that starts and runs after an 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 on the wiring in order to check for an engine miss or for a stall.

•	Check for a malfunctioning main relay. A faulty main relay can cause an engine that cranks but will not run and prevent illumination of the MIL. Refer to Main Relay Circuit Diagnosis .

•	Check for a faulty ignition-coil fuse.

An intermittent malfunction may be caused by a fault in the ignition system electrical circuit. Inspect the wiring harness and the components for any of the following conditions:

•	Backed out terminals.

•	Incorrect mating of terminals.

•	Broken electrical connector locks.

•	Incorrectly formed terminals or damaged terminals.

•	Faulty terminal-to-wiring connections.

•	Physical damage to the wiring harness.

•	A broken conductor inside the wire insulation.

•	Corrosion of electrical connections, of splices, or of terminals.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

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 that was stored when the fault occurred. The information is stored in the scan tool for later reference.

The PCM uses the CKP sensor for engine reference. Without engine reference signals there is not any spark or any fuel injector pulse. DTC P0335 sets after 3 seconds of cranking the engine if the CKP sensor signal is not present.

The PCM uses on the CKP sensor for engine reference. Without continuous accurate reference signals, there is not any reliable spark or any fuel injector pulse. The engine speed display should be approximately 260 RPM while cranking. If erratic values are displayed, the engine reference signal is not stable enough for the engine to start and to run correctly.

The PCM uses on the CKP sensor for engine reference. Without continuous accurate reference signals, there is not any reliable spark or any reliable fuel injector pulse. An ignition reference low circuit that is shorted to ground causes a faulty reference signal to be sent to the PCM, but does not set DTC P0335.

This step checks the TP sensor, the ECT sensor, and the MAP sensor for a faulty signal. A faulty sensor input to the PCM may cause a fueling condition that results in a no start.

This step determines if the fuel system pressure is within specifications with the ignition ON and with the fuel pump running. The fuel pump may be operated with the Output Control feature of the scan tool if the fuel level is more than 20 percent.

This step checks for adequate secondary ignition voltage at the spark plugs.

This step checks for faulty secondary ignition wires.

This step checks for correct resistance in the ignition coil secondary windings.

This step checks the ignition control circuit from the PCM.

This step checks for an ignition signal from the PCM while cranking the engine. The PCM sends a fluctuating voltage to the ignition coils after determining the engine speed from the CKP sensor.

Step

Action

Value(s)

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Check for DTCs with a scan tool.

Is a DTC P0335 set?

Go to DTC P0335 Crankshaft Position (CKP) Sensor Circuit

Go to Step 3

Observe the Engine Speed parameter on the scan tool while cranking the engine.