Pug 306 Lambda system control problem

Basically 1) the lambda sensor doesnt have sufficient control of the fuelling to cause a stall (i.e. enough of a rich or lean condition)- it only affects fuel trim within a +/- 15% range, and 2) the lambda sensor will not be heated sufficiently to produce a realistic signal until ~ at least 5 mins from cold start. In anycase the ECU will disregard the o2 sensor signal until a certain coolant temp and run time from startup have occured, and run in open loop mode, deriving the fuelling purely from the stored map + compensation from CTS and ATS + a small amount of trim from what its adaptive memory.

So, although you may have a fault with the lambda sensor system which needs checking out and rectifying, it won't be causing your stalling when starting from cold. More likely its overfuelling from either an oil filled MAP sensor hose, or CTS fault, or along those lines...

Tim..

A couple of weeks ago I drove up to Nottingham and back from London. I put some injector cleaner in the tank. For a few starts it didn't stall from cold, then it went back to normal, ie stalling from cold starts. When starting it after 5 mins of warming up it doesn't stall. Also I've had a look at the MAP sensor, and it seems to be ok, but two out of the three wires that link to it were rubbing and were bare and touching. I put insulating tape round these wires. Could this be the problem? I could look at these wires again and re-insulate them alot better. Many thanks for your info.

The lambda sensor doesn't effect the mixture on a cold engine.

Only if they were worn through or shorting.

Common cause of poor running while warming up is the coolant temperature sensor - it has a large effect on the mixture.

Thanks for that but any ideas what is causing the car to stall if it isn't the lambda sensor? I can see no air leaks, and all hoses seem ok.

Only thing I did notice and rectify was three leads coming from the MAP sensor. Two of the were wearing against a plastic hose clips, and were quite bare. I put insulating tape round the two wires. Could these need replacing?

It would probably be worth buying Mr Haynes Engine Management book - I'm not sure if the latest version covers your car exactly. but much of the fault finding is common to many. And cheaper than just guessing.

In the past 6 weeks I have replaced the stepper motor and the engine temp sensor with new parts.

I'm just trying to eliminate all diy efforts before I take it to a dreaded garage.

always nice to see people out there giving advice who havent the faintest idea what they are talking about dont be insulted guys most of the people i work with in the motor trade are exactly the same its why people are driven to guessing games using out of date equpment from the likes of gunson

The message from "Cookacat" contains these words:

And more to the point - it's far from clear which bit he didn't like.

Ahh - but he works in the trade. This automatically means he knows what he's talking about.

The message from "Dave Plowman (News)" contains these words:

And doesn't need to explain to us - just sneer and suck air through his teeth.

What is it the last few weeks - we've had a flood of these people.

Yup. They have to gain credibility by explaining properly problems that defeat others before doing that with justification.

But of course it's easier just to try and appear clever.

I notice our AC 'expert' from across the pond who didn't know the correlation between BTUs and watts seems to be a bit quiet...

Thanks for your help guys. I'm gonna bite the bullet and take it to a garage. it needs a service, and hopefully that may sort out the problem in turn.

the 206 suffers from a fairly common cold start routine problem and as of yet there's no guaranteed fix

good luck with it

miner.-

but the point is still valid the dealer has the equipment needed and you could easily spend a fortune fitting unneeded parts just because a fault on someone elses car needed a certain part to cure it doesnt really mean you need the same part if in doubt at least buy a wiring schematic and check the systenm yourself for wiring faults but to just keep fitting parts is a waste of money

i'm not sneering ,,,,,,,,,,the car needs to go to the dealer gunsons equipment is s**te thats it

The message from Mindwipe contains these words:

Are you saying that what his reader says is a fault 54 (or whatever it was) isn't a fault 54? While their analogue stuff might be somewhat flakey they'd be hard pushed to design a code reader which returns the wrong codes.

Similar advice was given earlier in the thread.