Topic

Good evening - last October some nice people relieved me of my catalytic converter and SS backbox on my 04 MGTF. I've just bought a new aftermarket CAT but wanted to know which oxygen sensor i need to buy - I know they have cut the wires but as i put the car away over the winter have yet to fully investigate the damage underneath .
Also i'm looking at a Gravity SS back box on e-bay - does anyone have any experience of them - are they any good /too noisy etc  
The Cat comes with a fitting kit but the exhaust does not - what else might i need ?

Hi and welcome to the forum

Sorry to hear about the hassle of cat theft.

I assume that you car is mk2 F or a TF as the mk1 only has one probe which is well up on the manifold.

If you follow the wires up from where they were cut you will find the plug.

Experience tells me it is worth spending the extra to get a genuine probe as they last much longer than the cheap ones.

James

Hi Robbie,
                  Really sorry to hear about your cat and exhaust. For exhaust fitting kits I would go onto Mike Satur’s site. They are really good. I would also recommend going for mg genuine o2 sensor. I would try Good old Rimmerbros.
Lastly I would consider using some antisense on o2 sensor threads only(avoid getting any on sensor) to make future removal much easier. I used some antiseize- permatex 81343. I sourced the permatex and an o2 22mm sensor socket on good old Amazon. Good luck. Simon.  

 

 

Just be aware that a lot of cheaper cats contain the bare minimum of active mesh and getting through an mot can be a right palaver.
I got sick of the battle to get the  annual emissions  to pass and bought a genuine cat. That was 6 years ago and the car has flown through each year without having to mess around.  

Hi Guys yes its an 04 plate Sunstorm 135 TF with believe it or not 98000 miles on it ( head blew at 42k under previous owner at 42 k and was replaced with the stronger landrover part) . Its not in great condition but its a bit of fun and budget is quite important in this repair but not at the expense of operation..
Yes i won't skimp on the probe - prices vary from circa 25 to the bosch at around 90 .
With regards to the box i had a MG Owners club SS one but that was £300 and look what happened . This gravity unit is 209 compared to the Toyo at around £150 and Mike Satur at £356 so it sits within  my budget range - just wondered if anyone had bought one ?
I'm planning to do the full investigation this weekend as there was a bit of the heat shield left on the drive under the car so may need a new on of those as well but i'll trace the wires up and take the engine cover off to see where they go . 
    

Hi Robbie,
                The o2 sensor is found between ecu and back of airbox on my car. It is black and had 4 wires coming out of it. It has a plug-in tab and needs to be pulled upwards to free it from the mounting plate. The push in tab at the bottom of the connector can be swapped over to the the connector of new sensor. I would try and leave old o2 sensor in at the moment and use old cut wires to tie around new sensor so that your can pull it up into the engine bay. I have an old heat shield that is intact and but needs resilvered if you want that. I will try and post photos below of o2 sensor connector.

 

Hi All and thanks for the comments and the photo SIMS . I've had a look under the car now and thankfully they seem to have unbolted everything except the sensor . The heat shield is still in place as all they had done is ripped a little bit off when the removed the fixing bracket ( so thanks for the offer SIMS but it think i'm ok with that ). Still had no comments re the Gravity exhaust so still not taken the plunge on that one. 
One question - i cannot see any fixings /bracket for the missing CAT - should there be one there or does it rely being fixed to the down pipe and the exhaust ? 
Thanks for the picture of the sensor - i'll order one and try to do that next weekend 

Hi SIMS I may be being a bit thick here but have just had a look in the enginefrom the boot by the ECU and cannot dsdsee where the lambda valve comes up or plugs in - please see attached photos - any help appreciated 
Robbie 

Hi Robbie,
                  I have a LE500 but I have looked at the pre SAIC MGTF manual and it should be in the same area. As you have an 04 plate the there should be pre and post cat o2 sensor.
I have copied the page from manual.
Have you followed the wires upwards from underneath the car where they cut it off assuming they are still there.
There should be the remnants of the harness if they pulled the whole o2 sensor wiring out with the cat. 
Sorry can’t be of much more help
Good luck

Simon

Hi SIMS I may be being a bit thick here but have just had a look in the engine from the boot by the ECU and cannot dsdsee where the lambda valve comes up or plugs in - please see attached photos - any help appreciated 
Robbie 

The plug for the sensor sits under the airfilter box and on top of the gearbox.

The cat is held in place by the three bolts and nuts at each end.
The centre pipe with the flexi has one mounting hook and the silencer has two.