1984 440 lambda light?

[Ian Fife]

I have a 440 with the B20F engine (Renault based I believe). In the last few weeks the green lambda light on the dash has started to come on from time to time. If I switch of the ignition and then on again it usually clears the warning light. The light coming on seems to be associated with idling when not fully warmed up.
Any suggestions as to what this might indicate and what I should check please? The car is running fine so I am tempted to leave it, but I suspect this may be an MoT fail point if it happens to come on during the MoT test.

Ian F.

[dcw]

Well, various things could be sending your emissions wrong, which is what that light implies, but my first thoughts would be either that the catalytic converter is starting to pack up perhaps, or else the lambda sensor itself could be giving up the ghost.

Have you read the error codes from the engine management system? It's the procedure using the flashing LED on the little black box on the passenger side strut, quite weldocumented on here if you do a quick search. That might point you in the right direction....

David

[Ian Fife]

Thanks David. I guess checking the error codes would be the best place to start. I just wasn't sure what the light actually signified - it can't be the emissions leaving the exhaust system as far as I can see, because the sensor is before the catalyst? So perhaps the light coming on indicates that the exhaust gasses at the lambda sensor are outside the range that the catalyst can deal with?
I didn't want to replace the catalyst as I couldn't see how the lambda sensor could detect whether it was working or not?

Ian F.
VOC member

[dcw]

Originally Posted by Ian Fozzard

So perhaps the light coming on indicates that the exhaust gasses at the lambda sensor are outside the range that the catalyst can deal with?

Hi Ian

I think you're right: the handbook for my 1995 480 (same thing in this respect I think) just says that the light "...means that the exhaust gas emissions are no longer in accordance with the specifications and are potentially harmful for the catalytic converter and the environment..."

If you can check your error codes first I'd say that would be best - it's a pretty basic system (no surprise given its age!) but it does work. I'll assume you know how to do this or have found it on here, but if not say so and I or others will guide you with pleasure!

David

[Ian Fife]

Hi David and all, used the diagnostic system this afternoon and it worked just as it should! I got one fault code from socket 2, a 2-1-2 code which indicates "Oxygen Sensor: Not responding or faulty".
So surprisingly the lambda warning light on the dash has led to an indicated fault with the lambda probe!

Since the car appears to be running OK (perhaps a little lumpy and hesitant when just warming up, but nothing that's a problem) I wonder whether I should replace the lambda probe? Perhaps wait until the light comes on permanently (it is very intermittent at present)?

Any views most welcome,

Ian F.

[Anadinolin]

Probably best to replace when you can, your mpg will suffet

[dcw]

Ian, glad the diagnostics worked OK!

I'm with Anadinolin on this one - I'd do something about it (have a go at cleaning it perhaps? or, more likely, replace it) as soon as you can because it's not going to get any better, your mpg will undoubtedly suffer and your emissions are almost certainly out, which of course won't help your MOT prospects...

David

[Ian Fife]

Originally Posted by dcw

Ian, glad the diagnostics worked OK!

I'm with Anadinolin on this one - I'd do something about it (have a go at cleaning it perhaps? or, more likely, replace it) as soon as you can because it's not going to get any better, your mpg will undoubtedly suffer and your emissions are almost certainly out, which of course won't help your MOT prospects...

David

Thanks David. Just scanning Eurocarparts web pages and see they list 3 different lambda sondes, all three wire, for my year of 440. I did ask them which one and of course they replied that I needed the most expensive one on the list!
Other suppliers also list more than one option.

Does anyone know how I might identify the correct lambda sonde, or does it make little difference (except to the wallet) which one I fit?

thanks,

Ian F.

[Anadinolin]

Originally Posted by Ian Fozzard

Thanks David. Just scanning Eurocarparts web pages and see they list 3 different lambda sondes, all three wire, for my year of 440. I did ask them which one and of course they replied that I needed the most expensive one on the list!
Other suppliers also list more than one option.

Does anyone know how I might identify the correct lambda sonde, or does it make little difference (except to the wallet) which one I fit?

thanks,

Ian F.

hard to tell, depends on the maker of the object in question and what you want to do, cheapness to me = poorer quality and sooner to fail - it could last for the life of the car, who knows?