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what do you know about lambda sensors?



Hi, guys.
Generally, it's not just bout the lamdas, it's about ECU.
As far as I know lambda provides info that ECU uses to adjust the ignition and the time of fuel injection to correct the fuel/mixture ratio. But the ECU also uses the pressure sensors and the one, sitting in the throttle (can't remember the appropriate word in english, sorry).
Several of my friends after installing ss (so called "free-flow") exhaust (and removing the catalysator to improve gas flow) have got some problems: unstable engine work with no load, increased fuel consumption and decreased perfomance. They haven't removed the lamda itself, just the cat.
So here's my idea: after the cat was removed, the temperature reduces and lambda is no longer in it's working temp. range, wich, I bielive, is about 300-400 C for th so-called "hot" lamda, wich is most common. So the ECU is emulating this info (not too precise, I guess) wich is causing the problems, I mentioned before.
Have you ever met such a problem? Or, wich I more tend to bielive, removing catalysator is illegal in UK and noone of you have removed it?
Please, tell me more about it.
More on this later....

I'll dig out my Renault 21 Turbo with emission control system manual tomorrow and see what I can find...with regards to removing the cat,its not really a problem providing your car was registered before July 92.
Anything thereafter required a catalytic converter for the MOT test (unless you got a friendly MOT tester that could be persuaded to 'look the ohter way'!! :wink:
With regards to your running problem,I've had a similar thing only it does very intermittantly so not really worried about it :wink: :wink:
Catch ya later (soz for the late reply) :oops:
Roj (21TOC Technical)
thanx for reply anyway.
hope, you'll find something interesting.

I wonder what do you, people do to a catalytic convertor, when mounting uprated exhaust system?
Waht is the difference between std exhaust and what you call perfomance exhaust? Is it just the steel, it's made of + wider tubing + more pleasant for both eyes & ears back box? Or it's de-cated system with a differently adjusted resonator box (but still ss & wider tubes)?
cat removal

mines gone 91 j no probs 'n' no silencers either, decated 21 sounds horrific dont it? :twisted:
The cat restricts airflow and when this is off it can tend to rev alot better and pull a little more, or so I found with my 21 which had a cat....also sounds better and with some other mods you get lovely pops and bangs from exhaust as well as flames.
So your engine feels OK after de-cating?
Any sensible changes in perfomance or fuel consumption?
How close is your lambda to the turbo?

Lambda sensor is about 12" before the bottom end of the downpipe. As for catalytic converter's, iv'e removed a fair few from 21T's with no ill effects save a little extra performance.
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