WS7 Exhaust gas Analysis (Petrol only)

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: 0.506      HC: 188     CO2: 14.08    O2: 1.4

Low oxygen means the engine is running rich. As engine running rich, high HC coming out in exhaust gas. High CO2 is also caused by rich condition but high CO telling us that there is not much O2 in the exhaust to convert it into CO2 and also the catalytic converter is cold yet to convert it into CO2.

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:  0.476     HC:  221     CO2: 14.35     O2:  0.84

The engine is running more rich in this scenario. High HC, CO2 and low O2 are the signs of  rich condition of the engine. High CO may be because of low O2 availablity to converter it into CO2 or may because of cold catalytic converter.

4. Run the warm engine at 2500 RPM, record the four gas readings: Explain what is happening within the engine referring to the four gases:

CO: 0.713    HC: 249    CO2 14.06     O2: 1.09

O2 is now seems increasing. It means the engine is going toward rich side. CO2 is  not changing much. HC is going high because of high RMP and more fuel is coming into the cylinders. CO is increasing because of high RPM and also may not converting into CO2 because of cold catalytic converter.

5. At Idle, create a lean condition with an air leak or vacuum leak, record the four gas readings:

Explain what is happening within the engine referring to the four gases:

CO: 0.08     HC: 3745     CO2: 3.65     O2: 16.10

High O2 in exhaust gas shows the engine is running lean but on other hand high HC means its running rich. But here high HC does not mean that its running rich because low CO and CO2 values with high HC means the fuel is not burning proper in this scenario because of vaccum leak

6. Accelerate the engine, by blipping the throttle a few times (don't rev too high and damage the engine) and watch how the gas readings change. Record the four gas readings when CO is highest. Explain what happening within the engine referring to the four gases:

CO: 3.638    HC: 304    CO2:  11.29     O2:  2.83

High CO, HC and Low CO2 means the fuel is not buring properly because of lack of sufficent O2 for proper burnung because blipping of throttle sucking less air as compare to fuel going into the cylinders.

7. Disconnect one spark plug wire, ground it with a jumper wire, then record the four gas readings as the emgine Idles. Explain what is happening within the engine referring to the four gases:

CO: 0.07    HC: 104     CO2: 12.3     O2: 4.43

High HC and O2 in exhaust gas may be because of unburnt fuel in one cylinder . Low CO and high CO2 are because of catalytic converstion of converter.

8. If you can get it, disconnet 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: 0.09    HC: 92     CO2: 12.26    O2: 0.14

There is not much changes in the gas values as it is the same thing to disconnet the spark plug and take the harness out from one of the injector because there will not fuel burning in one of the cylinder in both cases.

9. Optional: Make other changes to the cylinder at idle, such as turning on the air conditioning or rocking the steering wheel. Note the change you made: turning the AC on and rocking steering wheel both.

Explain what is happening withing the engine referring to the four gases:

CO: 1.069    HC: 160     CO2: 14.7    O2: 0.14

With AC on and rocking steering wheel, more power is needed to do so. To compensate this need, engine will work hard and need more fuel and because the engine is at Idle so not more air can enter through the throttle. Thats' why even HC is burning properly but because of low air, some coming out as unburnt. High CO2 because of high combustion and more CO in exhaust because of low O2 to convert it into CO2 by the catalytic converter.

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

With vehicle having catalytic converter, the CO and O2 values would be low and CO2 value would be high but the vehicle without it would have CO and O2 values high in the exhaust gas and CO2 would be low.

11. Explain what the light off point means and what happened?

12.  On lambda, O2 sensors why do they have 1,2,3,4 or 5 wires and what do these extra wires do?

 Two wires are the battery positive and negative wires and third wire is a sensor wire which bring the signal from sensor to ECU and forth wire is ground wire for the sensor.