SYMPTOM DIAGNOSIS
Symptom checks cannot be used properly unless problem is actually present while vehicle is being tested. To reduce diagnostic time, ensure battery voltage is okay and starter motor turns engine over before attempting to diagnose symptom.
Check engine mechanical condition (compression pressure, valve timing, etc.), wiring harness and connections (terminals not corroded or pushed back), and vacuum hose (not disconnected or leaking).
Also check for correct tire sizes, as recommended by manufacturer. Ensure wheels rotate freely (brake drag or bad wheel bearings). Symptoms available for diagnosis include the following.
- Engine Does Not Start Or Is Difficult To Start When Cold
- Engine Does Not Start Or Is Difficult To Start When Warm
- Uneven Idle Or No Idle With Cold Engine Or During Warm-Up
- Engine Starts But Stalls
- Idle Speed Exceeds Specification
- Poor Acceleration With Cold Engine Or During Warm-Up
- Engine Stalls While Driving
- Poor Performance
- Engine Run-On (Dieseling)
- High Fuel Consumption
- Engine Knock
- Engine Runs Unevenly Over Entire Speed Range
Note. When working on Digifant and Motronic systems, use symptoms listed only as a diagnostic guide. Specific symptoms for Digifant and Motronic systems are not available from manufacturer.
INTERMITTENT PROBLEM DIAGNOSIS
Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to computer setting a Diagnostic Trouble Code (DTC) which may help in diagnosis.
If problem vehicle does not produce a DTC, monitor voltage or resistance values using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.
When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.