Transcript A.S.T. Training Presents:
A.S.T. Training Presents: Quick Check Diagnostics
What are the average shop’s
dilemmas?
• No profit in driveability work.
• How to Diagnose today’s vehicles.
• High cost of equipment. • Who should do driveability work. • Charging for diagnostic time.
• Do I really want to do driveability work?
Tonight’s Seminar Agenda
1. Discuss Necessary vs optional equipment.
2. Discuss
hypothetical
vehicles and gather current diagnostic procedures.
3. Discuss in detail, problem
highly profitable
, new diagnostic procedures.
4. Follow
Quick Check Diagnostics
Worksheets.
Equipment
Necessary
1. Volt Ohm Meter 2. Scan Tool 3. Information Source 4. Lab Scope 5. Low Amp Probe 6. Fuel Pressure gauge
7. Automotive Common Sense Optional
1. Ignition Scope 2. Gas Analyzer
Diagnostic Job #1
1999 Volvo
Customer Complaint:
Battery Goes Dead
after 2 days of sitting.
Service Manager: Charged customer 1 hour diagnostic time. This charge does not include repairing the vehicle.
What would you do in your shop?
3 Possible Tests
1. Check TSB’s 2. Test Battery 3. Check For Drain on Battery
What Could Happen
1. Technician checks for drain on battery the conventional way by removing the negative battery cable and installing his amp meter in series with the cable and battery post. He finds an excessive draw and identifies the cause of the fault to be a faulty mercury switch inside the trunk, which keeps the trunk light illuminated. 2. Customer comes to pay his bill and pick up vehicle.
3. Vehicle will not start.
4. Vehicle gets towed to dealer to re-flash prom. Several hundred dollar charge is applied to you!
Quick Check Test
Several late model vehicles will have unwanted effects if we disconnect the battery cables. To perform a safe parasitic draw test, be sure to use an inductive low amp probe!
Diagnostic Job # 2
1989 Buick Century
Customer Complaint: Runs rough / No Power & Check Engine light on.
Service Manager: Charges 1 hour diagnostic time and promises to call before repairs are performed.
Technician: Found trouble codes 34 MAP sensor high & 45 Rich exhaust
What would you do?
Possible Diagnostic Steps
1. Diagnose trouble codes 2. Perform fuel and ignition system tests 3. Search for quick tips. (troubleshooter) 4. Perform engine mechanical tests Vacuum Compression Cylinder Leakage
Quick Check Tests
Diagnostic Job # 3
1992 Ford Taurus
Customer Complaint: Intermittent cut out hot.
Service Manager: Charges customer 1 hour diagnostic time, and tells you that the vehicle has been fine for several weeks now…….
Technician: Hates service manager’s guts!
Possible Steps
1. Drive car and park outside…no problem showing up.
2. Perform scan tool diagnostics 3. Hook up a bunch of equipment and drive or run vehicle until problem shows up. 4. Perform ignition and fuel systems conventional testing.
5. Guess at what is most likely the cause 6. Go home sick……
Quick Check Tests
This calculates to over a half an amp drain, using the 10mv = 1 amp scale.
We need to know if there is a drain on the battery, but if we disconnect the cable and use our amp meter, we may turn on some unwanted lights. What can we do?
Attach your low amp probe around the negative battery cable.
Remember to zero your probe!
If you think that your vehicle is running out of fuel, try using a pressure transducer. If you see a gradual decline all the way to a point of stalling then you are on the right track. What else can you use one of these for?
Missing Ramp = Open Injector Abnormally High Ramp = Shorted Injector
“No Clue”
Ignition Diagnostics
• Listen to the complaint.
• Formulate an attack plan.
• Think like the PCM. { strategies } • Compile best diagnostic tests for problem at hand.
• Check reference materials. Example: TSB & Silver Bullets • Follow analytical diagnostic procedure like the ones provided here.
Capitalize on the power of your scope!