Pug 306 Lambda system control problem

I recently used a gunsons unit to flash the fault code from my PUG 306 2.0
XSi 1997 reg. Basically it stalls when starting from cold. I thought it was
something to do with lambda sensor. The gunsons unit gave me code 52 which
in it's code book means the car has a fault with the Lambda system control.

Now is this something I can fix myself? I.e. put in a new lambda sensor or
lambda system control or is this a garage job? I'm pretty handy with the
car, not the best but I can muddle through. The Haynes manual I've got isn't
much use with this 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 <rpEJc.275$>

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

 

Pardon me for asking what the problem is. I thought this was a forum for
asking other people's advice. If you cannot help, please don't patronise.

 

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

 

The message <>

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 shite
thats it

 

The message <40f98c67$0$6446$>

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.