E.C.C. Trouble Diagnoses (Models with catalyzer) - How to Perform Trouble Diagnoses for Quick and Accurate Repair (Cont'd) - Diagnostic Worksheet

There are many kinds of operating conditions that lead to malfunctions on engine components.

A good grasp of such conditions can make troubleshooting faster and more accurate.

In general, feelings for a problem depend on each customer. It is important to fully understand the symptoms or under what conditions a customer complains.

Make good use of a diagnostic worksheet such as the one shown below in order to utilize all the complaints for troubleshooting.

Worksheet sample fields — Customer name (MR/MS), Model & Year, VIN, Engine #, Trans., Mileage, Incident Date, Manuf. Date, In Service Date. Symptoms: Startability (Impossible to start, No combustion, Partial combustion, Partial combustion affected by throttle position, Partial combustion NOT affected by throttle position, Possible but hard to start, Others); Idling (No fast idle, Unstable, High idle, Low idle, Others); Driveability (Stumble, Surge, Detonation, Lack of power, Intake backfire, Exhaust backfire, Others); Engine stall (At the time of start, While idling, While accelerating, While loading, Just after stopping). Incident occurrence (Just after delivery, Recently, In the morning, At night, In the daytime). Frequency (All the time, Under certain conditions, Sometimes). Weather conditions (Not affected); Weather (Fine, Raining, Snowing, Others); Temperature (Hot, Warm, Cool, Cold, Humid, °F). Engine conditions (Cold, During warm-up, After warm-up); Engine speed scale 0 to 8,000 rpm (2,000 / 4,000 / 6,000). Road conditions (In town, In suburbs, Highway, Off road (up/down)). Driving conditions (Not affected, At starting, While idling, At racing, While accelerating, While cruising, While decelerating, While turning (RH/LH)); Vehicle speed scale 0 to 60 MPH (10/20/30/40/50). Check engine light (Turned on, Not turned on).