Technical Excess emissions

[blu73]

Well I can't say I've ever sat and watched my lambda correction value while my car is running, but i can tell you from that video that the sensor itself appears to work, 450mV is equivalent to stoichiometric and its oscillating above and below that number on your meter which is exactly what this kind of sensor should do.. I don't know how the ecu comes up with this correction value though and therefore its hard to exactly understand what it means..

I know what you are saying, lambda 1.0 is fully stoic mixture but how a car with a narrowband sensor can spit out a steady number i don't really understand to be honest. It must be related to the sensor of course but you can see the sensor going below and above 450mV as expected and that means its reporting lean then rich then lean then rich in an endless cycle and the ecu should then use that to make corrections to keep it within a set parameter. Those readings from the sensor oscillating like that prove that its not constantly rich though or it would be staying above 450mV all the the time..

Which is kinda of what Jack and myself were saying earlier, there is no way this system can tell you how rich or lean it is, its simply not possible with the setup these cars have, its not how narrowband lambda sensors work; so what really is that value because its not telling you the actual lambda of the exhaust gas cause, it can't.. and it is labelled as a correction value as well not just lambda. I seriously think at this point it needs to go on the proper test equipment to see what's actually coming out the tailpipe. Just because the ecu is deciding that it needs to put extra fuel in (what this lambda correction probably really means it doesn't necessarily mean its running rich, it could mean its merely adding fuel to keep the mix right. And when you have your emissions tested they don't read this number from your ecu, they measure what comes out the pipe which gives you an actual lambda reading not a correction value. Hope that makes sense to you.
The only thing i might do prior to that is take the sensor out and clean it, with the car being run for who knows how long with the stat innards removed it could be pretty coked up from running a too cold on idle and running an enriched mix.


The water out the exhaust, thats normal. Water is a by product of combustion, the cars been sat idling for a while so the exhaust pipe won't be hot hot all the way to the back and therefore the water condenses in the pipe. If you were to drive it the pipe would get hot and the water would be out the exhaust before it condensed back into liquid

 

[ct3im]

That won't work because the throttle potentiometer is only part of the system the map sensor is involved.
Are there any leaks in the exhaust manifold ? Exhaust front pipe?

Aparently no problem in exhaust pipe , i could tell you , last year when I lost in MOT I have replaced CAT including front pipe but not solved.

might onto something here, its only a narrowband sensor so it can't possibly be tell the ecu how lean/rich the mixture is, it can only flip between rich and lean so i think this figure its spitting out is probably misleading you to think its running really rich when its not.. Which kinda leads me back to getting a printout from the test centre off the gas analyser telling you want all the actual levels of different gases out the tailpipe are.
I'm inclined to think it might be okay now, and if its not it'll be a leak in the exhaust or intake or the CAT is now weak from the engine running too cold and the ecu enriching the mixture as a result for a prolonged period.
From what little I've read on this topic, the lambda signal is a useful diagnostic tool but not on its own. For one, as i previously mentioned its a narrowband so doesn't tell you how rich/lean it is and secondly its an O2 sensor, doesnt tell you the levels of the other gases which you need to make any concrete diagnosis.

Aparently no problem in exhaust pipe , i could tell you , last year when I lost in MOT I have replaced CAT (removed from a working car) including front pipe but not solved.

In video is possible to see the voltage at lambda in my opinion is runing but not go more 0,6 , aparently runing 0,1to 0,5 or 0,6.

I have checked other posts in forum and the people do reference to the value lambda must read they must be in values arround min 0.97 to max 1.03 to have a correct (accepted) misture, In my car that value is 0.70 / 0,75 , I know this value not good , in this state the motor working for 20/30 min at +_800rpm the sparks goes black , but if I run fast it clean and goes to “normal color” .

Last year a friend provide one same model car to I read the parameters and compare with mine , and in that car the lambda correction I read value 1.
Other mechanic is the first to advertise me about that , he said if that value readed in lambda if is not 1 it mean the mixture is not 14,7 air per 1 fuel.

I have another injection body , include the admission collector , I have buyed a more long fuel pipe to test if the injector is not loosing fuel in the o ring , have buyed joint glue to guarantee no false air is entering . In next days I expect I have more news about this.

 

[blu73]

yes of course, sorry i wasnt trying to imply there isnt an underlying issue here by saying just take it for the test, more that with an actual readout of the gases coming out the tailpipe it might give you more of an indication of whats going on with the combustion - you could just go to somewhere that does the tests and ask them to do a few tests, one at idle, one at medium engine speed and another at fast engine speed to see what the car actually puts out rather than just saying there is something wrong because the correction value is wrong. I agree that value is wrong.

Could be beneficial to do a compression test if you haven't yet just for peace of mind. Keep us posted

 

[jackwhoo]

Have you used Iaw to look at map sensor readings ? Are they plausible ?
Any fault codes stored in ecu?