O2 Lambda Sensor replacement

davidhowson

Junior Member
Messages
474
Never let it be said that I don't tackle some serious jobs with my car!

Next on the list is to drop the cats to have a look if they are all ok (and possibly replace with something a little more appropriate)
and the change the O2 sensors.

I think I got a great deal from Opie Oils on these genuine Bosch sensors
 

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Zep

Moderator
Messages
9,110
That, I have to say, is an absolutely blinding deal. Good effort!
 

davidhowson

Junior Member
Messages
474
I'm wanting to take to old cats off to check them out as they have hit various raised things in the road over the years.
The O2 sensors and all the bolts have come out really easily but how the heck do I get the four bolts out of the manifold end!
These are difficult to get to the top two and the bottom two have been attacked by road grime, salt and general wear and tear to the extent I can't even get a socket on one of them.
 

Zep

Moderator
Messages
9,110
I'm wanting to take to old cats off to check them out as they have hit various raised things in the road over the years.
The O2 sensors and all the bolts have come out really easily but how the heck do I get the four bolts out of the manifold end!
These are difficult to get to the top two and the bottom two have been attacked by road grime, salt and general wear and tear to the extent I can't even get a socket on one of them.

I bought new bolts when mine had to come off to do the AC Compressor. I think the best bet is to carefully grind the heads off the bolts and then use a stud extractor or drill them out. Once they are off and you put a small drill through them that will probably wind themselves out of the other end of the hole.
 

Gp79

Member
Messages
1,393
I bought new bolts when mine had to come off to do the AC Compressor. I think the best bet is to carefully grind the heads off the bolts and then use a stud extractor or drill them out. Once they are off and you put a small drill through them that will probably wind themselves out of the other end of the hole.

My exhaust mounting bolts were in the same state, cut the bottom ones off easily, then dremel for the top two, was very slow work.
The exhaust took me 6-8 hours to remove completely due to wasted fittings
 

davidhowson

Junior Member
Messages
474
I think I need more than O2 sensors!!

I thought something wasn't right when I started this exercise; so dropped the side I knew had been hit to reveal this:

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And then this;

56114137145__49DE38F1-59B4-42E7-A674-0FDFF9F51772.jpg
 

dunnah01

Member
Messages
648
Definitely becoming a 'common' problem. All modern cars have these in-built hand grenades so I smell a US Class Action.

This was mine on the QPV after 50k. I grubbed out the remains of the primary and secondary cats on both sides put 200 cell cats in the primary casings then welded the cans back up. So a £200 upgrade in the end - every cloud and all that..

The cats on the QPV are buried up in the engine bay and a real PITA to get at but a combination of sockets, extensions, UJs and swearing either freed or broke all the studs to the manifold. Once out I ground off the studs and replaced them all.

I had to replace the right bank pre and post sensors which were damaged when the cat catastrophically failed but no CELs now and running and sounding the way it should.
 

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davidhowson

Junior Member
Messages
474
When I finally removed all the debris, I could see that the squashed bit of the pipe was just full of bits and how any gasses were getting through is beyond me.
The same section has also been grounded quite a number of times over the years and this has restricted further the pass flow.
I don't think the other side is going to be like this, as it was the near side that took quite a knock on a raised manhole cover.

I had to cut one bolt head off as it was so rusty and damaged, the other three came off using a long bar. Interestingly, the bolt heads seem to be half inch rather than 13mm! Is that right?
 

TimR

Member
Messages
2,656
Be interesting to see how bad it is. My very limited understanding of the issue is that it doesnt necessarily take physical abuse to effect failure..?


Grtzzz...!
 

dunnah01

Member
Messages
648
Be interesting to see how bad it is. My very limited understanding of the issue is that it doesnt necessarily take physical abuse to effect failure..?


Grtzzz...!
No signs of any physical abuse on mine - just age related I think. Feels much better having stainless rather than ceramic cores now.
 

Spartacus

Member
Messages
3,184
I had a look for lambda sensors on the Opie oils site but can t seem to find any listed for Maseratis, any advice ?
 

TimR

Member
Messages
2,656
Are they both wideband sensors?
Looking at the intervals, I staggered they recommend 160K kms. A narrow band sensor could be expected to last longer whilst still being reliably accurate.
The tuner I've had work on bike engines for me tells me he replaces his sensors every month or so... :eek:
 
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Spartacus

Member
Messages
3,184
Thanks , Am I right in thinking that the GS with American spec exhaust ( two bolt flanges ) has differant length leads than the 4200 ones ?
 
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