[Engine] Spluttering below 2500 rpm

[oilyrag]

If you look at the black plastic fuel rail that supplies the injectors the right hand end has a cap like a tyre valve dust cap - with the ignition off ease this open - it may have some fuel under pressure. With the cap removed put a piece of tubing on the threaded stub and the free end in a jar/bottle. When the ignition is switched on the pump should run (possibly only briefly) and this will allow you a fuel sample. Alternatively looking at the left hand end of the rail you'll see where the fuel supply line attaches. This has a fiddly clip which when undone allows you to take the supply pipe away and again sample fuel.
A cautionary note - this fiddly clip does not re-fasten that well and mine came off again when I went to start the car. It now has a tie-wrap over the top of it to lock it firmly in place.
I think you'd be looking at a weakening mixture as the problem (guessing!) as you open the throttle at lower revs. The engine expects a dose of fuel when the throttle opens and you may be getting a dose of air. Do check for any inlet manifiold leaks, cracked pipes, loose connections, any of which could be allowing additional air in.
Good luck!

[Softweigh]

Thanks Oily Rag I did find that the screws I replaced in the air filter housing were too short so it could suck air??? Still only splutters after a long highway trip but not as bad ... Is it worth also checking the o2 sensor ? If so can you simply disconnect it to see if that's the issue or must it be changed ..that could cause an incorrect mixture ...in the meantime doing a careful check for air leaks on the intake side .. it's our rainy season here so you have to wait for a break in the weather to do stuff. There is an o2 sensor in the pipe below the manifold and the ECU doesn't make a fuss if I disconnect the plug but I need to do it when it's idling rough .. What is the sensor mounted on the manifold ? Another O2 one???

[oilyrag]

The air cleaner box screws will have no effect - any air leaks will need to be downstream of the throttle body. Wouldn't recommend randomly pulling any plugs off - see attached doc - as you may well upset the ECU and throw up codes that you then can't clear. 
Once you have done all of the cleaning/servicing/leak checking then it's going to be difficult to make much more progress without delving into the ECU and any codes that might be happening when the problem arises.
  Scan_20220617.pdf (Size: 4.54 MB / Downloads: 5) .

[oilyrag]

The attachment is upside down to make it easier for you to read!

[Softweigh]

Thank Mate ..Love your sense of humour but I promise we down walk upside down !! Thanks for all the really useful information. I took the van to a European specialist who charged me $150 for a diagnostic test but said they couldn't determine any error because someone had over-ridden the rad fan relays ..(I have since taken that single 12v wire off as the fan works fine) Maybe it needs to go to a Citroen dealer ... quite a few of our local car/electronic stores have OBDII scanners ..Would one of these below help me at all???

https://www.jaycar.com.au/obdii-engine-c...gLuHvD_BwE

[oilyrag]

This is where an oldie like me comes unstuck when dealing with technology that doesn't date from the 1930s , but (re)-start a new thread on the subject as members like Zion have a great understanding of how to collect data and help interpret what's happening.  
Good luck!

[Softweigh]

Thanks! Me too ..I would much rather have a carb and distributor, points and condenser. I used to race a Ford Anglia (the one with the bird poo proof rear window) we put a Fortina 120E 1500 cc motor in it bored out to 1850cc ..stage 4 cam and twin Weber 40 DCOE carbs ..Now THAT I can work on!! No ECU and no sensors!!!!

[Sol]

That scanner may help somewhat, but generic ones only get engine codes (P-xxxx) so they are limited on the Citroen.

Ideally you want live data, especially AFR (air-fuel ratio) and Injector Fuel Trim plus MAP etc. You won't get that stuff from any generic set I've tried, even Torque Pro is woefully poor at reading internal parameters from the Citroen vehicles.

If you can get Diagbox from eBay with the Interface (as a kit) and install on a laptop, that's the gold standard and will tell you everything.

Look for a seller who offers a VM version, and run it using VirtualBox / VMware Player, then hand the USB interface over to the VM where it will work, saves a whole lot of heartbreak trying to install Diagbox, as it's a major pig to do from scratch.

If you find something on Oz eBay, post the link and we can have a look.

[Softweigh]

Thanks Zion

This van has a bit of a sordid history so for your and my friend Oily Rag's benefit here is a brief summary plus what happened today on a local trip :
When I bought it and gave it a test drive I noticed the radiator fan was running continuously. The rat fink salesman said “Oh all European cars that come into Australia have the fan running as soon as you turn the ignition on” Total rubbish of course and I noticed a pink wire running from the relay box to the fan relay box so when the ignition was on the relay came in and ran the fan at high speed ..a situation which only should happen when the gauge almost is in the red.
I wasn’t happy with this running all the time so I cut the wire and installed a toggle switch on the dash so I could manually kick the fan in if I needed to. After great advice from the forum guys they assured me that this “mod” was not needed and true to their word I ran without the fan “hotwired” and in fan found that the fan DID come in when my temp gauge read around 110 degrees (however I also discovered both fuel and temp were over-reading by between 15 and 20%) so that means the fan actually comes in around 95 degrees and drops out at around 90 degrees)

Right..on to today … as the fan over-ride switch is always off I thought I would try and kick it in when I came to an intersection to see if the rough idling and stuttering stopped and amazingly it did!!! Now I have a temp issue as well so when I drop the engine temp idle stays steady at 1000 and the van pulls off smoothly … I did change coolant around 2 years ago but was wondering if a fresh coolant would help even without the fan running all the time??? I left the fan over-ride running on my home run today (lots of traffic lights) and everything was smooth and my gauge never went over 90 degrees and idle never dropped below 1000 and all take offs were smooth

Time for some fresh coolant ???? ..could it be as simple as that with the spluttering and rough idle as I cannot rely on the temp gauge! or maybe there is an ECU error telling the fan when to kick it???

[oilyrag]

Well, it could just be the air where you are, but clearly someone had 'overcome' a fault in the past by running the fan continually. What seems (to me!) unclear is why there is no great change in temp gauge reading and that overheating, if that's what it is, wouldn't normally cause the symptoms that you have.
If the symptoms go away immediately when the fan is switched on it points to something odd happening with the fan /temp sensor / relay - maybe an intermittent short that is being picked up via the ECU/ignition system and that's generating a mis-fire or mis-fuelling. 
If the issue is simply directly related to a rise in engine temperature then there are some checks to do. 
With the engine cold bleed out any air via the point at the thermostat housing and at the bulkhead where the heater pipes go in. Check or replace the pressure cap.
Cleaning out the system with a flushing agent and making sure that the rad isn't choked with dust might help.
An after-market fan switch - Kenlowe etc.- which can be adjusted and allow you to have more control over temp settings could do the job - if, as you say, the fan fixes the issue (no matter what the causeeffect was) then, on an old van, that might be a cheap option.