System Diagnosis - Fuel System

FUEL SYSTEM DIAGNOSIS

Poor cold start
^ Low volatility
^ Injector deposits-Refer to Fuel Delivery and Air Induction / Testing and Inspection / Procedures / Fuel System Deposits
Poor warm up
^ Low Volatility
Poor cold weather performance
^ Low Volatility
Poor hot start
^ High Volatility
Poor hot weather performance
^ High Volatility
Vapor lock
^ High Volatility
Spark/detonation
^ Low octane
Poor fuel economy
^ High volatility
^ Injector deposits-Refer to Fuel System Deposits
^ Intake valve deposits-Refer to Fuel Delivery and Air Induction / Testing and Inspection / Procedures / Fuel System Deposits
^ Low octane
Excessive exhaust emissions
^ Low volatility
^ Sulfur Content
^ Injector deposits-Refer to Fuel System Deposits
^ Intake valve deposits-Refer to Fuel System Deposits
Reduced Power
^ Low octane
^ Intake valve deposits-Refer to Fuel System Deposits
^ Injector deposits
^ Improper volatility
Rough/unstable idle
^ Injector deposits-Refer to Fuel System Deposits

Always start with the Powertrain OBD System Check. The Powertrain OBD System Check table will identify other tables for specific checks, such as:
^ Fuel System Pressure Test
^ Fuel Injector Balance Test
^ Fuel Inj Coil Test - ECT Between 10-35 Degrees C
^ Fuel Inj Coil Test - ECT Outside 10-35 Degrees C
^ Idle Speed Control Check

DIAGNOSTIC AIDS
If there is no fuel pressure check all component and circuit grounds.