V6 non starting/stalling

[smaustralia]

I have a 2000 24v Exclusive very lightly used but only in city traffic with only 69,000klms. It has been regularly serviced but recently (12mths) has been getting harder to start and stalls more and more at intersections while cold.
Cleaning the throttle body, New spark plugs and a 200kl. expressway run had no effect. It performs well, (but with noisy intake on acceleration), when hot and starts easier then but not as easily it should. It is very 'course' at idle but not missing. Fuel consumption is getting much worse and my garage sais they cannot get the LEXIA to contact with the ECU ???
As there are not many 24v XMs in Oz ,and they are generally trouble free, I dont have much experience available to address the problem.
Possibly needs an engine ECU, or a Air flow /temp sensor or..........?????????
Thanks in advance
Peter

[xantia_v6]

Welcome to the forum. It is good to hear of another low mileage late V6. I have a 1999 V6 with manual transmission in France that has now done 75000 km.

It would be worth putting some effort into getting Lexia communication with the ECU, maybe check for continuity from the ECU connector to the diagnostics connector. Maybe try another Lexia.

My pick for your fault is the MAP sensor on the back of the manifold. They fail ( or get accidentally disconnected) causing hard starting, bad running and high fuel consumption.

They are a common part, but there were 2 versions with different connectors used on the ES9.

It would also be worth checking or changing the ECU coolant sensor (the green one) and the air temperature sensor (grey).

There is more ES9 experience on http://www.frenchcarforum.co.uk than here.

[CitroJim]

Peter, a warm welcome from another ES9 owner, both in XM and Xantia guise..

I quite agree with Mike's list of things to check..

It seems almost common that the Lexia cannot communicate on an ES9 V6. I'm currently running around with an ECU on test in my XM that speaks perfectly to the Lexia on mine but fails to speak when fitted to its own car... As yet we do not know why..

First question is, can the Lexia 'see' any other ECUs? If other ECUs can be read then that suggests the basic socket is OK (receiving power and so on). I apologise for stating the obvious, but the keypad must be unlocked to be able to read the engine ECU.

[Charles M]

Welcome! Nothing to add technically, but I take it from your handle that you are another SM owner, or even the Peter McLeod of Citroen SM Australia?

[xmexclusive]

The Lexia no access to a particular ECU is a regular problem.
It happens with genuine kit as well as the clones.
The ability to talk to other ECU's is not always a good guide.
30 pin sockets and the leads to the Lexia are the most common problems.
With this system the Lexia addresses each ECU over its own set of pins contacts and wires.
The Lexia uses a set of relays to select a particular ECU and contact wire pair.
I have a jumper lead made up from a recovered PSA plug that lets me wire into 30 pin contacts.

John

[CitroJim]

That's a fair point about the Lexia John. Sorry, should have thought of that.

If you can see other ECUs then you do at least know the socket has the two power supplies it needs and the correct earths..

Clone Lexias can be very 'iffy', especially on the older cars. For that reason I rarely use mine on the XM and usually use the ELIT which generally is very reliable. Hence why I forget...

Good idea to have a breakout box. Do you find this can help read an ECU when the standard leads can't?

[xmexclusive]

Hi Jim

Getting 30 pins in a single plug to connect fully with the socket is virtually impossible to check.
The genuine Actia leads can still give problems and variable results.
One Indy I talked to about this had two sets of genuine leads.
He would try both if necessary.
He said that even then the results were not always consistent.
With clone leads the 30 pin plugs are a long way short of PSA plug standards.
They often need physically modifying to fit the car socket fully.
Only use 30 pin to round plug leads with Type 1 & 2 (Round plug) clone Lexias.
Only use 30 pin to 25 pin "D" plug leads with Type 3 (25 pin "D" plug) clone Lexias.
If you need to add an extra converter (round to 25 pin) lead in the chain between car and Lexia there will be wiring missmatch.
The electrical contents of clone Lexias can vary with each factories method of cloning.
As the study on FCF a while ago showed the PCB quality, circuitry and component count can be vastly different in clone Lexias.

John

[Jan-hendrik]

It would also be worth checking or changing the ECU coolant sensor (the green one)

I replaced this sensor about 2 years ago at about 54000 km, which cured stalling and hesitation when cold. This is the water temperature: injection sensor. This job is easy to do and the sensor itself is not expensive. I'd replace it before continuing with endless fiddling with the Lexia. Wish you success, Peter.

[marc61]

I replaced the coils on ours and it made a big difference, much more than changing the plugs. The symptoms were roughness, stalling and hot start difficulties.

Marc