I condone drugs that are not toxic.

Mercedes factories are located in America therefore
America makes mercedes.

I wish they made Sprinters too. They are fairly rare
on the lots.

Do they still make "ludes" ?

.

I thought Bert was the evil one!

Lambda sensor

The Lambda sensor(02 sensor) was introduced in 1977 in answer to ever
tightening automotive emission regulations.The sensor sits in the
exhaust system and monitors the amount of oxygen present in the exhaust
gases.

There are three major components of combustion:fuel,heat and air.The
combustible portion of atmospheric air is oxygen-28 %of air is
oxygen.If the correct ratio of fuel and air have been combined in the
combustion chamber,then all of the oxygen will be consumed during
combustion.If the engine is running rich,either too much fuel or not
enough air has been fed into the combustion chamber.Consequently,when
the engine runs rich there is almost no oxygen left over.When the
engine runs lean,either too much air or not enough fuel has been
delivered to the combustion chamber.The result is a high oxygen
constant in the exhaust system.

The Lambda sensor consist of two gas permeable layers of platinum
separated by a layer of zirconium oxide ceramic.When the temperature of
the Lambda sensor reaches 600 deg F.,the ceramic becomes conductive for
oxygen ions. The outer layer of platinum is exposed to exhaust
gases.The inner layer of platinum is exposed to ambient air.When the
percentage of oxygen is balanced between the inner and outer layers,the
ceramic will not attract oxygen ions from either side.When the
percentage of oxygen in the exhaust gases decreases,the Lambda sensor
begins to attract oxygen ions from the ambient air side and a voltage
is produced.

The output voltage of the Lambda sensor usually ranges from 100 to 900
mV. A voltage greater than 450 m V is considered rich;a voltage less
than 450 m V is considered lean.

Lambda Sensor Contamination

The Lambda sensor can be contaminated or damaged in several ways.

Leaded fuel is one example.The lead additive in regulator gasoline
forms a coating over the platinum,keeping the oxygen from passing
through to the ceramic layer.

A second possibility for contamination is some RTV silicone
sealants.Use caution when purchasing engine repair sealants to ensure
that they are Lambda sensor safe.Many silicone sealants also form a
coating over the platinum keeping oxygen from passing through.

A third potential source of problems for the Lambda
sensor is soot.Soot results from an engine running extremely rich or
from the engine burning oil.Soot coats the Lambda sensor,preventing the
oxygen from penetrating the platinum layer and reaching the zirconium
oxide.

When working around the Lambda sensor,be aware that even small amounts
of voltage can damage the sensor.Do not allow voltage to go down the
wire to sensor.Even small voltages,such as those from an ohmmeter,can
damage it.

Vibration can cause damage to the internal connections of the Lambda
sensor or even destruction of the sensor.Sources of vibration would
include hammering on the exhaust system,driving over rough roads and
driving at excessively high speeds.

Finally,heat can damage the Lambda sensor.Although the sensor requires
high temperatures to operate,excessively high temperatures can melt
it.These temperatures can occur in the exhaust system when there is a
crack in the manifold.

Testing the Lambda sensor

A simple test of the Lambda sensor involves two steps.

First,disconnect the connector between the Lambda sensor and the
computer.Connect a high impedance voltmeter between the sensor and
ground(earth).Then start the engine and allow it to run until the upper
radiator hose is hot and pressurized.Next,hold the Lambda lead to the
computer with one hand and touch the positive battery terminal with the
other hand.This delivers a small voltage to the computer,causing the
computer to believe that the engine is running rich.The engine rpm and
the Lambda sensor voltage should drop.

If there is no response,connect the Lambda wire that goes to the
computer to ground.This makes the computer believe that the engine is
running lean.The rpm and the Lambda sensor voltage should both
increase.

If the system passes either test,then the system is working properly.If
the rpm changes but the Lambda voltage does not,replace the Lambda
sensor.If neither change,check for continuity on the wire to
computer.If the wire is good and the connection is good,replace the
computer.