1. Tips and Tricks NACAT 2001 Winnipeg, Manitoba, Canada July, 2001 James D. Halderman Sinclair Community College Dayton, Ohio jdhalderman@aol.com

2. 5-Gas Exhaust Analysis Five-gas analysis is sometimes difficult for students to understand. Tip: “Your Nose Knows” If you smell exhaust, it is unburned fuel (HC).

3. 5-Gas Exhaust Analysis If your eyes water, it is oxides of nitrogen (NOx plus water around your eyes forms a mild nitric acid solution which burns your eyes).

4. 5-Gas Exhaust Analysis If you get a headache or feel dizzy, it is likely caused by excessive CO emissions. Think of CO meaning “clogged oxygen” or not having enough air for the fuel or having too much fuel for the available oxygen.

5. Easy to Remember Specifications w/o CAT w/ CAT HC 300 ppm or less30 - 50 ppm or less CO 3% or less0.3 - 0.5% or less O 2 0% - 2%0% - 2% CO 2 12% - 17%12% - 17% NO X less than 100 ppm @ idle less than 1,000 ppm @ WOT

6. Quick and Easy Tip CO should equal O 2 CO = rich indicator O 2 = lean indicator If both are the same, the mixture is OK

7. 5-Gas Sample Question #1 What is wrong? HC and CO 2 = high and CO and O 2 = low

8. Answer to Question #1 The problem is most likely ignition (“spark stuff”) related. It is OK for CO and O 2 to be low. It is OK for CO 2 to be high (high efficiency)

9. 5-Gas Sample Question #2 What is wrong? HC = 3 ppm O 2 = 20.8% CO = 0% CO 2 = 0% NO X = 3 ppm

10. Answer to Question #2 The exhaust probe was not in the tailpipe! No carbons (CO and CO 2 ) indicate no combustion occurred. Tip: Think of CO and CO 2 as ash left over from a fire. No carbon – no fire!

11. Fuel Injection Tip Use a stethoscope on an injector. Should hear a “clicking” sound not a “clunking” sound Students really understand fuel injectors if they hear them work.

12. Quick and Easy Trick Use a stethoscope to listen at the fuel return line from the fuel pressure regulator.

13. Quick and Easy Trick If you hear fuel moving back to the tank, the fuel pump pressure is greater than regulator pressure. If you do not hear fuel moving, the fuel pump or the fuel pressure regulator could be defective.

14. Sensors High Authority sensors include: 02S – when in closed loop MAF MAP ECT – especially at engine start TP

15. Sensors Low Authority sensors include: IAT BARO (if separate from MAP) TFT

16. Sensor Tip “If in doubt – take it out.”

17. Tip Explanation A high authority sensor can be “skewed,” Which means that it is working OK but not accurately measuring the engine condition. If the engine runs better with a sensor disconnected, the sensor is either defective or is somehow measuring the condition incorrectly. If disconnected, PCM substitutes a replacement value.

18. Student Projects Lighter Socket to Meter Heated Oxygen Sensor to Meter Extension Cord and Plug to Check Relays Fused Meter Lead Fused Jumper Wire Wheel Speed Sensor to Double Banana Plug

19. Lighter Socket to Meter Fused Lighter Plug 274-335/Double Banana Plug 274-717

20. Heated Oxygen Sensor to Meter

21. Extension Cord and Plug to Check Relays

22. Fused Meter Lead Inline Fuse Holder 270-1213

23. Fused Jumper Wire

24. Wheel Speed Sensor to Double Banana Plug

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