Emissions problems - Lambda sensor?
21 November 2004, 12:05 AM
#1
Scooby Regular
Thread Starter
Join Date: Dec 2001
Location: SE London
Posts: 331
Likes: 0
Received 0 Likes
on
0 Posts
Emissions problems - Lambda sensor?
Hi All,
Went to get the Legacy (MY'93 UK Turbo) MOT'd today and it failed on emissions. Only mods are a H&S backbox (both cats still in place).
Have been told that a dodgy Lambda sensor might be the cause of the problem, but I haven't a clue what it does or how it effects the emissions of the car. Can anyone enlighten me?
Went to get the Legacy (MY'93 UK Turbo) MOT'd today and it failed on emissions. Only mods are a H&S backbox (both cats still in place).
Have been told that a dodgy Lambda sensor might be the cause of the problem, but I haven't a clue what it does or how it effects the emissions of the car. Can anyone enlighten me?
22 November 2004, 09:38 AM
#2
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Following extract taken from www.lambdasensor.com...
The Lambda Sensor is at the heart of emission control continually monitoring the exhaust gas. Carbon Monoxide (CO) is produced by the engine. If the mixture supplied is too rich then CO will be high and visa versa. Having plenty of fuel (Rich) the engine will try to burn as much as possible, using up all available Oxygen, conversely if there is not sufficient fuel to maintain a correct burn then the excess Oxygen will pass into the exhaust system.
Rich mixture = High CO = Low Oxygen
Weak mixture = Low CO = High Oxygen
The Zirconia lambda sensor, by using precious metals, can determine the Oxygen difference between atmosphere and the exhaust gasses. The greater this difference, the higher the voltage it will produce, up to app 1volt. Lambda sensors will not operate until around 300 deg. They are heated by the exhaust and often have their own heater element. Single & twin wire lambda sensors have no heater element and are usually situated near or in the manifold, three & four wire sensors have an built in heater to aid rapid warmup and may be placed further downstream.
The Lambda Sensor is at the heart of emission control continually monitoring the exhaust gas. Carbon Monoxide (CO) is produced by the engine. If the mixture supplied is too rich then CO will be high and visa versa. Having plenty of fuel (Rich) the engine will try to burn as much as possible, using up all available Oxygen, conversely if there is not sufficient fuel to maintain a correct burn then the excess Oxygen will pass into the exhaust system.
Rich mixture = High CO = Low Oxygen
Weak mixture = Low CO = High Oxygen
The Zirconia lambda sensor, by using precious metals, can determine the Oxygen difference between atmosphere and the exhaust gasses. The greater this difference, the higher the voltage it will produce, up to app 1volt. Lambda sensors will not operate until around 300 deg. They are heated by the exhaust and often have their own heater element. Single & twin wire lambda sensors have no heater element and are usually situated near or in the manifold, three & four wire sensors have an built in heater to aid rapid warmup and may be placed further downstream.
Thread
Thread Starter
Forum
Replies
Last Post
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
28 December 2015 11:07 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM