For 1990-2009 cars

### Strategy Based Diagnostics

1. Perform a Diagnostic System Check - Vehicle before using the symptom tables, if applicable.
2. Review the system operations in order to familiarize yourself with the system functions. Refer to Disassembled Views , Engine Component Description , Drive Belt System Description , Lubrication Description.

All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system problem. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis.

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the Engine. Refer to Checking Aftermarket Accessories.

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

• | Check for the correct oil level, proper oil viscosity, and correct filter application.

• | Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.

• | Compare the engine sounds, if applicable, to a known good engine and make sure you are not trying to correct a normal condition.

### Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Base Engine Misfire without Internal Engine Noises

• | Base Engine Misfire with Abnormal Internal Lower Engine Noises

• | Base Engine Misfire with Abnormal Valve Train Noise

• | Base Engine Misfire with Coolant Consumption

• | Base Engine Misfire with Excessive Oil Consumption

• | Engine Noise on Start-Up, but Only Lasting a Few Seconds

• | Upper Engine Noise, Regardless of Engine Speed

• | Lower Engine Noise, Regardless of Engine Speed

• | Engine Noise Under Load

• | Engine Will Not Crank - Crankshaft Will Not Rotate

• | Engine Compression Test

• | Oil Consumption Diagnosis

• | Oil Pressure Diagnosis and Testing

• | Oil Leak Diagnosis