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Discussion Starter #1
Driving today and the fated return to dealer scare mongering lit up...

quick scan with multi scan this evening reveals i have a lambda issue..

But a few quick questions.. why does the Gta require four of them.. will two do if the fronts are fooled with adapters

Where is the best place to get genuine Bosch ones as i,m guessing buy cheap buy twice on these

And with P1155 / P0150 Lambda 2 / P0155 showing up which lambda should i start with please..

All knowledge great-fully received and soaked up in a sponge like fashion ... thanks in advance..
 

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Don't assume that lambda fault codes are caused by faulty lambdas for a start.

Could be plugs, coil packs, HG's :eek: exhaust leaks, intake trunking split.

Mine's throwing a similar hissy fit atm too...

Using a genuine bosch lambda is a given but afaik, the only real difference between the various narrow band sensors is the length of the connecting wire. So others will fit, but may have a longer or shorter wire than necessary. My Dad's usual trick is to find out how long the wire is and factor that into his eBay search.
 

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What is MES telling you?

Pre-cat ones are telling the ECU to flip between slightly rich and slightly weak by signalling between 0.05V and 0.75V, about once a second. If you take those out, the ECU will definitely be annoyed. The post cat sensors under the car are all about catalyst efficiency - they could be rock steady 0.46v approx. If the catalysts aren't working, then the after cat lambdas will be either cycling or high/low which will upset the MCSF light.

Look at the graphs in my image thread - aside from the weird bits, the pre-cat lambda graph is what yours should look like. If one is cycling very slowly, it is probably knackered. If it is flatlining (rich or lean) then it could well be something else. E.g. if you have a dead coilpack, then the pre-cat lambda in that bank will be signalling very rich (loads of oxygen pre cat) and if the catalysts are in good order, then the post cat will be normal as the cats will be doing the combustion (and getting very hot).
 

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Discussion Starter #4
Don't assume that lambda fault codes are caused by faulty lambdas for a start.

Could be plugs, coil packs, HG's :eek: exhaust leaks, intake trunking split.

Mine's throwing a similar hissy fit atm too...

Using a genuine bosch lambda is a given but afaik, the only real difference between the various narrow band sensors is the length of the connecting wire. So others will fit, but may have a longer or shorter wire than necessary. My Dad's usual trick is to find out how long the wire is and factor that into his eBay search.
Plugs are new coil packs are new will check exhaust and intake first .. thanks for the advice
 

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Discussion Starter #5
What is MES telling you?

Pre-cat ones are telling the ECU to flip between slightly rich and slightly weak by signalling between 0.05V and 0.75V, about once a second. If you take those out, the ECU will definitely be annoyed. The post cat sensors under the car are all about catalyst efficiency - they could be rock steady 0.46v approx. If the catalysts aren't working, then the after cat lambdas will be either cycling or high/low which will upset the MCSF light.

Look at the graphs in my image thread - aside from the weird bits, the pre-cat lambda graph is what yours should look like. If one is cycling very slowly, it is probably knackered. If it is flatlining (rich or lean) then it could well be something else. E.g. if you have a dead coilpack, then the pre-cat lambda in that bank will be signalling very rich (loads of oxygen pre cat) and if the catalysts are in good order, then the post cat will be normal as the cats will be doing the combustion (and getting very hot).
will check again.. as was pushed for time yesterday.. think i recall open circuit on lambda 2 .. removed pre cats so might be an issue.. as above ignition all new so hoping it is just a dead sensor or even a broken wire.. will investigate further..
 

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Discussion Starter #6
sorted this today was the front bank pre cat lambda ... all is well again for at least 8 hours before i start it again..
 
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