Citroen C5 rough running-ecu problem?

Unless you get a diagnostic scan carried out and see what shows , you could be fitting parts not required , plus labour costs .

True, the scan initialy showed an injector fault, that injector was replaced but it still shows that injector is faulty so I suspect an ECU issue, any thoughts?

you need to check the associated wiring from the ecu to the injector but it does sound like an ecu fault.You could try having the ecu checked/repaired

Could test injector wiring with a noid light test kit , this explains .

https://www.youtube.com/watch?v=5MmR-wXddVw

Injector/ECU it may be
but if I'm reading this right then it gets worse/bad when its hot?
But starts fine when cold?
A big chunk of initial diagnosis is talking to the driver.
Or interrogating might be closer.
Your guy seems to have done the right things but made a bit of a leap.
The next step I would take is cylinder compression when hot,
And if good I would then check the suspect injector pattern waveform trace with an oscilloscope.
Which I'm guessing your guy doesn't have.
So my advice is find a diagnosis specialist locally and explain the fault in detail listing what has been done so far and asking them to check the injector waveform on the 'scope.
My ECU tester charges around £50,
Which is how much I'd charge to 'scope the system.
But you might get the ECU back as passed.
Then you back to finding a garage with an oscilloscope.
.

Thanks, the garage is an independent Citroen specialist, the checked compressions, all good, also the coil pack, new, and good.
It does start well, runs well for a short time and then runs rough, sometimes seeming to clear with speed, sometimes not!!
The Garage ran diagnostics and fault code was with injector 1, they fitted new injector but fault remained, wiring looks ok back to the ecu.

Yup.
Ok but that confirms my concern.
Is it loosing compression when hot,like a tight valve clearance?
But back to the 'scope.
an oscilloscope can display either voltage or current,
if No 1 compared with the others differences can be seen
It might be the current ramp on #1 is different than all others indicating an ecu driver fault.
Sorry if I'm getting technical but these kind of faults can be only diagnosed by looking at the signal patterns on an oscilloscope.

if the fault code is specific to an injector and the injector has been replaced and the wiring /connections are good at ecu and injector the problem will be an internal ecu fault I would only scope it if it was an an intermittent misfire fault

I have come to the conclusion the ECU is faulty, found another at a breakers, is this just fit or is there a set up needed, my remote locking facility has long gone so not worried if this is "lost" also radio etc.

Any thoughts?

you wont be able to just fit ecu due to trans code.you will need plips bsi and ecu for everything to work properly.

What is a plips bsi?

Do I need to get someone to set it up or?

the bsi communicates key codes etc with engine ecu for immobilser.the remotes are programmed to the vehicle so bsi recognises keys and informs engine ecu correct key present to enable vehicle to start and run.I don't think you will be able to reprogram the transponder code into a second hand ecu.