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MG MGF Technical - What is a lamba sensord

My MGF has just failed it's MOT due to the emissions test. It failed due to the lambda reading. I have been advised to change the lambda sensor - is something I can do or do I need a garage. I can't fing the instuctions in the workshop manual so I'm not sure what it involves.

It also failed on the handbrake :o( Can this be tightened ?

Hope you can help
Derren Benton

The Lambda Sensor is an Oxygen Sensor in the Exhaust. You may have one or 2 depending on year. This gives a signal/s to the ECU to control fuel and hence Emissions. Cost is £120 to £60 for an alternative aftermarket.
It is essential that the test is done with a hot engine which may need a 5 mile fast run on the way to the MOT.
Handbrake failure is often due to piston seizure in one of the rear calipers.
Geoff F.

G. Farthing

It failed on...


DESC CRITERIA READING
Eng Speed 2500-3000rpm 2789rpm PASS
CO =< 0.30% 0.00% PASS
HC =< 200ppm 3ppm PASS
~ 0.97-1.03 1.052 FAIL

The engine was hot - oil temp gauge showed 120 as I purposely took it for a good spin before hand.

Will changing the lambda sensor do the trick. If it doesn't - what do I do next ??? I'm convinced the testing unit was at fault as it took them 20 mins to get it working.

I've now replace the rear brake discs/pads as they are not wearing correctly. There doesn't seem to be any pad contact at the outer edge of the discs - therfore, they have corrded.???
Derren Benton

Okay, failed miserably trying to change the sensor. It is bolted in at a strange angle. The workshop manual says to use a claw spanner - what is this ?
Derren Benton

Sorry, the workshop manual says use a 22mm claws foor spanner. Still not sure what one is ?
Derren Benton

This tool is made for your purpose:
http://www.amazon.co.uk/LAMBDA-SOCKET-SPANNER-WRENCH-TOOL/dp/B0012L5AW4
Jon F

A claw spanner is a ring spanner with a slot cut in it to allow a cable or pipe to pass through. your Sealey dealer will have a special long socket to fit.
BUT the high temperature may have caused the thread to seize so soak it well with penetrant and use a good quality spanner. If you tear the thread then a dealer will sell you a new downpipe or a good engine shop will charge you £1:00 for a 16mm spark plug helicoil insert. 4th draw in my toolbox.
Geoff F.
G. Farthing

how about an MOT at another station?
Leigh

This thread was discussed between 16/02/2008 and 17/02/2008

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