Lamda sensor in the Y piece
Discussion
Bugger, on close inspection I have a third sensor which is fitted into the original Y piece 
Hadn't noticed this before as it's tucked away very low down. Something in my memory recalls someone repositioning this into the exhaust pipe just after the Y piece/exhaust clamp. I haven't spoken to Clive yet (who I'm sure will have the answer) but anyone had to do this? I'm hoping someone is going to say 'no you don't need that coz you're running Megasquirt......' Nice shiny new Y piece now sitting back on sofa in lounge
Thanks chaps,
Chilli
Hadn't noticed this before as it's tucked away very low down. Something in my memory recalls someone repositioning this into the exhaust pipe just after the Y piece/exhaust clamp. I haven't spoken to Clive yet (who I'm sure will have the answer) but anyone had to do this? I'm hoping someone is going to say 'no you don't need that coz you're running Megasquirt......' Nice shiny new Y piece now sitting back on sofa in lounge Thanks chaps,
Chilli
Thanks for the replies guys...
Still digging into this, but logic (mine so not very reliable) suggests to me that this third Lambda sensor, after the main CAT, is there to provide info to the ECU about oxygen content, after the exhaust gasses have passed through the main CAT. But, (here's my probably faulty logic), if you don't have a main CAT then what this sensor senses will be the same oxygen content as the two lambda sensors in the manifolds.... So what function does it serve?
I dunno
Still digging into this, but logic (mine so not very reliable) suggests to me that this third Lambda sensor, after the main CAT, is there to provide info to the ECU about oxygen content, after the exhaust gasses have passed through the main CAT. But, (here's my probably faulty logic), if you don't have a main CAT then what this sensor senses will be the same oxygen content as the two lambda sensors in the manifolds.... So what function does it serve?
I dunno
Sardonicus said:
Its a Wideband sensor and not Narrow band (TVR originals in manifolds) and has much wider operating/scaling range ideal for setting up ECU mapping rather than the very narrow windowed narrow bands, hope this make sense.
Yes it does, but I was of the belief that my two manifold sensors were (installed when the MS2 was)wide band.... probably wrong though.... 
Chilliman said:
Sardonicus said:
Its a Wideband sensor and not Narrow band (TVR originals in manifolds) and has much wider operating/scaling range ideal for setting up ECU mapping rather than the very narrow windowed narrow bands, hope this make sense.
Yes it does, but I was of the belief that my two manifold sensors were (installed when the MS2 was)wide band.... probably wrong though.... Sardonicus said:
Chilliman said:
Sardonicus said:
Its a Wideband sensor and not Narrow band (TVR originals in manifolds) and has much wider operating/scaling range ideal for setting up ECU mapping rather than the very narrow windowed narrow bands, hope this make sense.
Yes it does, but I was of the belief that my two manifold sensors were (installed when the MS2 was)wide band.... probably wrong though.... dumbfunk said:
If you're running a mega squirt then theres a good chance the two original sensors won't be connected to anything. My MS installation just uses the one wide band sensor only.
Sorry dumbfunk didn't see your post before posting my last.. methinks you're correct....Thanks,
Chilli
And to compound things, unless the heater circuits in the original narrow-band probes have been kept energised whilst you have been running on the new wide-band unit, chances are they will be toast as they don't like being sat in an exhaust stream 'cold' (ie as a surrogate bung).
Obvious place for the wide-band is in the collector of the new Y, but no reason why it could not go into the system a bit further back if you really don't want to alter the Y (a decent fabricator/welder will do it in 20 mins). Just make sure the tip of the probe does not enter where condensation might pool (ie don't fit from the bottom); also, WB controllers often don't like sensor leads being extended.
Obvious place for the wide-band is in the collector of the new Y, but no reason why it could not go into the system a bit further back if you really don't want to alter the Y (a decent fabricator/welder will do it in 20 mins). Just make sure the tip of the probe does not enter where condensation might pool (ie don't fit from the bottom); also, WB controllers often don't like sensor leads being extended.
Pupp said:
And to compound things, unless the heater circuits in the original narrow-band probes have been kept energised whilst you have been running on the new wide-band unit, chances are they will be toast as they don't like being sat in an exhaust stream 'cold' (ie as a surrogate bung).
Obvious place for the wide-band is in the collector of the new Y, but no reason why it could not go into the system a bit further back if you really don't want to alter the Y (a decent fabricator/welder will do it in 20 mins). Just make sure the tip of the probe does not enter where condensation might pool (ie don't fit from the bottom); also, WB controllers often don't like sensor leads being extended.
<This Obvious place for the wide-band is in the collector of the new Y, but no reason why it could not go into the system a bit further back if you really don't want to alter the Y (a decent fabricator/welder will do it in 20 mins). Just make sure the tip of the probe does not enter where condensation might pool (ie don't fit from the bottom); also, WB controllers often don't like sensor leads being extended.
I removed my original Lambda probes and sold them on Ebay for £60 recently however they were heated for the very short period they was still in situ after the MS install, I got fed up with looking at them hanging from my wiper blade rack doing nowt on a daily basis 
in fact it may of been you Pupp that gave me the link for the Allen bungs to fill the TVR holes 
Edited by Sardonicus on Wednesday 27th February 23:10
Why are y having to have your new y piece adapted, do only some cars come with said sensor. Why does the Clive y piece not come ready to install,did you order it without knowing and if so does Clive know? Very disappointing if he knows of such differences and didn't check what you have! I'm confused as usual, oh Chilliman I read your Marbles post, if it wasn't so unnerving I'd have found it funny. I've been away 2 days, I'm so un convinced I'm sure the f
ker will be back when I get into her! Keeping my fingers crossed, moral of the story, thank fk you did this so we can save our knuckles, back and general wellbeing! Lol. This dash off thing, I'm gonna do it just to take the fear of it away!
Back to topic, i realise it sounds like I'm having a go at Clive, no not at all but to find out the y piece needs more fettling don't seem right. Someone clear up my upset, I hate hearing of product that is not quite correct! Feel free to churn me up if I'm talking bks. Is it's Chilli's fault for not giving correct information or some other reason!
ker will be back when I get into her! Keeping my fingers crossed, moral of the story, thank fk you did this so we can save our knuckles, back and general wellbeing! Lol. This dash off thing, I'm gonna do it just to take the fear of it away! Back to topic, i realise it sounds like I'm having a go at Clive, no not at all but to find out the y piece needs more fettling don't seem right. Someone clear up my upset, I hate hearing of product that is not quite correct! Feel free to churn me up if I'm talking b
ks. Is it's Chilli's fault for not giving correct information or some other reason! Alun450 said:
Why are y having to have your new y piece adapted, do only some cars come with said sensor. Why does the Clive y piece not come ready to install,did you order it without knowing and if so does Clive know? Very disappointing if he knows of such differences and didn't check what you have! I'm confused as usual, oh Chilliman I read your Marbles post, if it wasn't so unnerving I'd have found it funny. I've been away 2 days, I'm so un convinced I'm sure the fker will be back when I get into her! Keeping my fingers crossed, moral of the story, thank fk you did this so we can save our knuckles, back and general wellbeing! Lol. This dash off thing, I'm gonna do it just to take the fear of it away!
Back to topic, i realise it sounds like I'm having a go at Clive, no not at all but to find out the y piece needs more fettling don't seem right. Someone clear up my upset, I hate hearing of product that is not quite correct! Feel free to churn me up if I'm talking bks. Is it's Chilli's fault for not giving correct information or some other reason!
Entirely down to me Alun, if I'd taken a closer look at the lower end of the existing Y I'd have seen the sensor and could've advised Clice accordingly..... Never mind mate, you live and learn ker will be back when I get into her! Keeping my fingers crossed, moral of the story, thank fk you did this so we can save our knuckles, back and general wellbeing! Lol. This dash off thing, I'm gonna do it just to take the fear of it away! Back to topic, i realise it sounds like I'm having a go at Clive, no not at all but to find out the y piece needs more fettling don't seem right. Someone clear up my upset, I hate hearing of product that is not quite correct! Feel free to churn me up if I'm talking b
ks. Is it's Chilli's fault for not giving correct information or some other reason! Chilliman said:
Alun450 said:
Why are y having to have your new y piece adapted, do only some cars come with said sensor. Why does the Clive y piece not come ready to install,did you order it without knowing and if so does Clive know? Very disappointing if he knows of such differences and didn't check what you have! I'm confused as usual, oh Chilliman I read your Marbles post, if it wasn't so unnerving I'd have found it funny. I've been away 2 days, I'm so un convinced I'm sure the fker will be back when I get into her! Keeping my fingers crossed, moral of the story, thank fk you did this so we can save our knuckles, back and general wellbeing! Lol. This dash off thing, I'm gonna do it just to take the fear of it away!
Back to topic, i realise it sounds like I'm having a go at Clive, no not at all but to find out the y piece needs more fettling don't seem right. Someone clear up my upset, I hate hearing of product that is not quite correct! Feel free to churn me up if I'm talking bks. Is it's Chilli's fault for not giving correct information or some other reason!
Entirely down to me Alun, if I'd taken a closer look at the lower end of the existing Y I'd have seen the sensor and could've advised Clice accordingly..... Never mind mate, you live and learn ker will be back when I get into her! Keeping my fingers crossed, moral of the story, thank fk you did this so we can save our knuckles, back and general wellbeing! Lol. This dash off thing, I'm gonna do it just to take the fear of it away! Back to topic, i realise it sounds like I'm having a go at Clive, no not at all but to find out the y piece needs more fettling don't seem right. Someone clear up my upset, I hate hearing of product that is not quite correct! Feel free to churn me up if I'm talking b
ks. Is it's Chilli's fault for not giving correct information or some other reason! http://www.ebay.co.uk/itm/Exhaust-Lambda-Boss-M18-... make sure you also fit the compulsory warning label though 
Edited by Sardonicus on Thursday 28th February 12:27
Andav469 said:
I also suspect it has something to do with your Megasquirt set up, I have changed the Y Piece on mine for a Clives Y Piece and had no third sensor in my system (Chimaera 500 1999).
Phew! I will be installing my new shiny Y piece and thought I had missed summat!Cheers
Phil
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