WS7

WS7Exhaust Gas Analysis

  

Make Nissan Model Cefiro Year 1996

Exhaust Analyser

CO0.00

Carbon Monoxide (CO) Caused by a rich mixture and not enough oxygen (HC + O2 can’t all complete to CO2, so Carbon Monoxide is created.

HC 3ppm

Hydrocarbon emissions (HC) also called Volatile Organic Compounds (VOC). Measured in parts per million (ppm)

CO2 0.09%

Carbon Dioxide (CO2) doesn’t cause pollution, used for diagnosis

           

O2 20.80%

Oxygen (02)

Start Cold(Engine Idle)

CO0.197% HC279ppm CO2 14.61% O2 0.31%

This reading indicated that the engine’s emission is running rich because HC and NOxs high cause by the cold start and the catalytic Converter is not warm up.

Warm Engine (Idle)

CO0.004% HC251ppm CO2 14.75% O2 0.19%

With the engine has warm, HC at 251ppm now decreasing but still not enough for a clean emission at this point. The problem is that the ignition time is not set to be ignited at the right time or before TDC. The timing adjusted is too far advance and fire the plugs before there is enough time for ideal vaporization, and so HC is creates.

Engine at 2500 RPM,

CO2.167% HC 372ppm CO2 13.42% O2 0.17%

With the warm engine at 2500 RPM we detect another problem with this vehicle’s emission. It’s possible this vehicle’s oxygen sensor is giving out fault reading. The O2 sensor is telling the system it is lean, so the system rich it up and that’s the problem here causing HC increase.

Rich mixture with extra propane (Idle)

CO 12.29%  HC 2161% CO2 6.44% O2 1.91%

With extra propane add, the ECU would not sense the fact more fuel is drawn in the cylinders causes increase on HC. With a limit of Air from Intake Manifold is not enough, causes O2 decrease. Bad mixture because of HC and Oxygen is not complete to CO2, so more CO is created.

Lean condition with an air leak or vacuum leak (Idle)

CO 0.66% HC 2001ppm CO2 9.3% O27.4%

Lean condition with the vacuum disconnected engine is under a load and fuel with no pressure, this induce heat to the engine temperature   causing increase of NOx and HC.

Accelerate engine, by blipping the throttle a few timesRecord the Four Gas readings when the CO is highest:

Idle 900 - CO 2.083% HC576ppm CO2 13.22% O21.00%

 As the accelerating blipping the throttle wide open and closed, this quickly withdrawn fuel and HC is create but less Carbon Dioxide and so CO is induces.

Disconnect one spark plug wire; ground it with a jumper wire, then record

CO0.501% HC1686ppm CO211.90% O23.61%

The increase on HC is cause by misfire from one engine cylinder, un-burn fuel occur and with less air affecting the mixture as results of low CO could not create more.

Disconnect one harness of fuel injector (engine idle)

CO0.114% HC153ppm CO211.84% O2 4.86%

With an unplug injector and no injection in one cylinder and engine temperature rise, this indicate decrease on HC and CO as CO2 and O2 increase.

Air Condition (on) 

 CO 0.119% HC25ppm CO2 14.52% O2 0.54%

With AC ON more power is needed, the engine withdrawn more fuel at the engine idle and with limit amount of air come through the throttle. At this state HC is properly burn but CO2 is high cause high combustion and more CO in tailpipe cause low O2 convent into CO2 by the catalytic converter. 

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

Vehicle having catalytic converter, CO and O2 values is low and CO2 value increase and with the vehicle without it, Value would be opposite.

The catalytic converter work to reduce fuel evaporation from exposing   to the atmosphere. One possible change is known tested is high CO from the engine exhausts entering the catalytic converter. This clean up CO gas and reduce it causing increase on CO2 from the tailpipe.

A vehicle without the catalytic converter is uncontrollable fuel emission, engine run richer, high level of gases.

On lambda, 02 sensors why do they have 1,2,3,4 or 5 wires and what do these extra wires do?

The Vehicle that we test has the O2 sensor with four wires.

Grey – Sensor Ground

Black – Signal for ECU

White – Power Heater

White – Heater Ground