2011年12月12日星期一

WS7 Exhaust Gas Analysis

Exhaust Gas Analysis

Make Ford     Model KA
1.  With the analyser probe sensing normal air, what are the Four Gas readings? Record the amount and then what it means:
CO   0.00      means: There is no CO in the atmosphere
HC   13ppm   means: Left over HC in the probe
CO2 0.00      means: No CO2 in atmosphere
O2   20.91     means: O2 level in atmosphere

2. Start the engine idling cold, and record the Four Gas readings
Explain what is happening within the engine referring to the four gases: 
CO 4.465     HC 18.39    CO2 9.88     O2 9.26 
CO is high as there is low O2 as it has been burnt; HC is high as there is unburnt gas due to condensationand rich air/fuel mixture; CO2 is lower because there isn't enough O2; O2 is high due to same gas not being burnt

3. When the engine has warmed up, record the Four Gas readings:
Explain what is happening within the engine referring to the four gases:
CO 0.018     HC 188     CO2 13.58     O2 0.38 

4. Run the warm engine at 2500RPM, record the Four Gas readings:
Explain what is happening within the engine referring to the four gases:
CO 1.114     HC 173     CO2 12.71     O2 1.64
CO is low because there is more O2 being burnt; HC is low because most of the gas is being burnt; CO2 is nearly good as combustion is efficient; O2 is low as all the gases are being burnt

5. At idle, run the mixture rich with extra propane, LPG, or carburettor cleaner, and record the Four Gas reading:
Explain what is happening within the engine referring to the four gases:
CO 1.8        HC 197     CO2 14.70     O2 0.79
we sprayed it with the eater starter fluid so doing a test after that we notice that the engine is running rich so higher HC due to unburnt fuel and also engine is less efficeint there is higher O2 as there is too much fuel to burn so this also means higher CO levels due to the rich condition

6. At idle, create a lean condition with an air leak or vacuum leak, record the Four Gas reading:
Explain what is happening within the engine referring to the four gases:  
CO 0.175     HC 95      CO2 7.75      O2 9.65
CO is low as there is more O2 to create CO2; HC is high as there is not enough fuel to burnt evens thing; CO2 is low because combustion is not efficient; O2 is high as it's not being burnt

7. Accelerate the engine, by blipping the throttle a few times, and watch how the gas reading change.
Record the Four Gas readings when the CO is highest:
Explain what is happening within the engine referring to the four gases:
CO 3.947     HC 2313    CO2 12.59   O2 0.58
CO is high as there is not a lot of O2 to create; HC is high as there is a lot of unburnt gas due rich condition
CO2 is low because combustion is not efficient

8. Disconnect one spark plug wire, ground it with a jumper wire, then record the Four Gas readings as the engine idles:
Explain what is happening within the engine referring to the four gases:
CO 0.582     HC 1291    CO2 12.40   O2 7.61
CO is low because there is a lof of air going through the exhaust; HC is high as one cylinder is not buring any gas; O2 is high due to on cylinder not burning

9. If youcan get to it, disconnect the injector harness connector from one injector on an engine that has one injector for every cylinder: Record the Four Gas readings as the engine idles:
Explain what is happening within the engine referring to the four gases:
CO 0.747     HC 217     CO2 11.68     O2 5.17  
CO is low due to air going through the cylinder; HC is low as there is less gas going through; CO2 is low due to inefficient combustion; O2 is high as there is one cylinder not burning.

10. Optional: Make other changes to the engine at idle, such as turning on the air conditioning or rocking the steering wheel. Note the change you made:
Explain what is happening within the engine referring to the four gases:
CO 0.300     HC 8        CO2 14.73      O2 1.017 
All gas reading good as engine only a little bit higher making combustion more efficient

11. Explain the different readings you would get from a vehicle with a catalytic converter and a vehicle without one and why?


A vehicle without a cat convertor would produce greater CO and HC as the CAT convertor creates a chemical reaction to change emission into something different that is less harmful to the environment .

12. Explain what light off point means and what happens?


In order for CAT convertor to work it has to be hot enough to work. CAT convertor is a device used to reduce the toxicity of the exhaust from the internal combustion engine .Most modern car engines control the amount of fuel they burn. That the Cat convertor has to get to certain level of temperature to start working

13. On lambda, 02 sensors why do they have 1,2,3,4 or 5 wires and what do these extra wires do?
One is ground, other one is signal and another can be heaters.

WS5 Scan Tool Diagnositics

Scan Tool Diagnostics

Warning: Be careful working around engines and exercise caution to avoid injury.
1. Scan Tool Data
1.1 Find a vehicle which is appropriate for the scan tool.
1.2 Connect the scanner, power it on, follow the instructions andinput the correct vehicle information it asks for so you can view the data.

1.3 Find the data for the information listed on the next page.Turn engine on to idle. Fill in the letter used to label the information and the value of that data.Note: not all vehicles will support all information, just find as much as you can. If the engine won't run, input the information with the key on, engine off.


Type of information (PID = Parameter Identification)

Letters to describe it
E.g. TPS
Value of data
Units for data
E.g. volts
Engine Load (how much air comes in)
AS
 1.30
 V
Engine RPM

E.S
 762
 rpm
Throttle angle

 TPS
 0.48
V
Engine coolant temperature
ECT
 69
 C'
Intake air temperature
IAT
49
C'
Fuel Injection opening pulse
injection time
 2.7
 ms
Transmission select position



Vehicle Speed



KM
Oxygen sensor(s)

O2
0.27
V
Fuel Trim




Idle control

IACV
 69
 %
Power steering condition



Air conditioning condition
 AC signal
 off

Exhaust Gas Recirculation (EGR)




Fuel Evap or Purge condition



Malfunction Indicator Light (MIL)



Barometric Pressure




Battaery


14.1
V






2 Trouble Codes or Fault Codes
2.1 Find where the Codes are listed
2.2 Record any codes, and what system and condition they describe in the chart below (Example: might be code number 21, for Throttle Position Sensor, signal voltage too low) If
there are no codes listed, put “none”.
The car's system as normal and there is no faults and the car also run good. If the car has any problem it will come up with trouble code . 

3 Lecturer put in Fault
3.1 Find your lecturer and have him create a fault under the hood (don’t look)

Record New Codes
4.1 Look up the codes now in the scan tool
4.2 Record the codes in the chart below. Also record what system is affected, and what condition is described.
when I checked through the scan tool it show me 2 problems in scan tool data but when I check for the codes it's didn' come up,we checked the data we got from before and then compared it and we got the TPS senor and Air flow sensor, that voltage was very high for TPS and the engine was running rough.

Find What Data Has Changed
5.1 Look through the scan tool data to see what PIDs (Parameter Identification of system voltages) have changed.
Which readings don’t make sense or don’t read what you would expect. Concentrate on the PIDs related to the codes.
5.2 Record the PIDs that have changed below:
I checked the data sheet and notice that the throttle position sensor voltage was very high that was 5.10 V when its normal that should be around 0.48V. That's what I got when it was normal and also i notice that the engine was not idling well so we notice that air flow sensor wasn't connected so the engine was running rough.


6 Visual Inspection to find fault
6.1 Do a visual inspection under the hood to find where the problem is. Use information from the code to know where to look for the problem and what type of problem to look for.
Describe problem you found:


I've already knew what I have to looking for when I opened up the hood,I found that the Throttle position sensor and the Air flow sensor were disconnected so engine wasn't idling well and also engine was running rough.I just had to plug back in the sensors i turned off the engine but the ignition on then I use the scan tool to clear out the faults and check it if it was cleared it was and the system was back to normal.I also checked the data sheet, the voltage was back to normal. Other ways for fix the faults codes or other light on your dash board you can remove the battery terminals for 30 seconds also you can remove the main engine fuse to get ride of the fault codes.
The importance of live data fault finding is that its very easy to know what's the problem on your car.
Scan tool is very handy to use now it makes the work easy and very useful for workshop to have one be makes job easier faster and can be done very quickly.