WS7 Exhaust Gas Analysis (Petrol Only)

Exhaust Gas Analysis 

I tested a couple of cars with the Exhaust Gas Analyzer, the first car was given mixed reading and found out the car had a exhaust leak which gave the O2 sensor a high Oxygen reading. The next car i tested the results follow.

Carbon Monoxide (CO) = .007
Hydrocarbons (HC) = 25
Carbon Dioxide (CO2) = 0
Oxygen (O2) = 207.9

When the engine was cold the the engine is running rich, this is why the HC is very high, (unburnt fuel). Also the CAT isn't working yet as the engine is not at running temperature. The engine is still running in open loop making it rich, this makes more CO.

CO = 1.9
HC = 180
Co2 = 13.3
O2 = 1.42


When the engine had warmed up i did the test again. The engine is now in closed loop and runs leaner. This leaves less HC in the exhaust and more CO2 because the mixture is burning properly. CO goes down because of good combustion.

CO = 1.51

HC = 130

Co2 = 13.8

O2 = 1.36

Next when ran the engine at 2500 RPM, and recorded the readings. It burned efficiently less air is left over because of good combustion.

CO = .6

HC = 73

Co2 = 144

O2 = .65

At idle again, we sprayed in CRC to run a rich mixture. HC rises in the exhaust because of more fuel to burn. CO goes up from incorrect burn and CO2 goes down. Less oxygen is left over because we have replaced it with extra HC.

CO = .8

HC = 115

Co2 = 14.2

O2 =  1.14

At idle, i created an vacuum leak and the engine and recorded my results. With a lean mix, HC goes right down, because of less fuel. In turn O2 goes up because less of it is used up to burn the fuel. CO2 goes up Because the burn is good and CO goes down.

CO = .2

HC = 75

Co2 = 14.5

O2 =  1.5

Snap Acceleration, CO goes up because of rich mixture not burning properly. CO2 goes down from poor combustion. HC goes right up because the injectors are spraying longer and O2 goes up from opening the throttle.

CO = 2.1

HC = 2000

Co2 = 9

O2 =  3.6

I disconnected one spark plug wire and grounded it with a jumper wire. This causes HC to rise because of no injection in one cylinder.

CO = 2.1

HC = 3294

Co2 = 8.2

O2 =  7.83

Summary


A catalytic Converter connects bad gases coming out of the car into friendly ones, thus HC, CO2 and CO will go down but the oxygen level will rise because the CAT is changing some of the gases into more oxygen and water.

The CAT becomes effective usually around 400 - 600 degrees F