Citroen c5 2003 Engine trouble

[Kristian27]

The short term fuel trim is governed by the readings from the oxygen sensor. What do the readings from the oxygen sensor do at the same time?

Bellow is a picture showing STFT and O2 bank 1 readings

could it be related to the MAP sensor ? (this car does not have MAF sensor)

[Kristian27]

when I changed the fuel pump, I only changed the pump itself, not the whole assembly. I am starting to think there might be a Pressure regulator in the assembly that is causing the fuel pressure to be too high/low? haven't measured the fuel rail pressure yet but will do.

[Paul-R]

I haven't followed the whole thread but here's a thought. Is the pump you fitted the correct one? For instance, is there a difference between petrol and diesel pumps and could you have used the wrong one?

[Kristian27]

I haven't followed the whole thread but here's a thought. Is the pump you fitted the correct one? For instance, is there a difference between petrol and diesel pumps and could you have used the wrong one?

Hi! I am pretty sure the fuelpump is the correct one. It was changed to try to fix the issue. It hasn not gotten any better or worse afterwards. The pump put in is the "MESSMER 770119A"

I am thinking that the "fuel pressure regulator" might be bad. So i will get the proper equipment to measure the rail pressure.

[Kristian27]

So I have now measured the fuel pressure, which is stable at 3.5 bars. But! I noticed the Negative terminal clamp on the battery was a little Slacks, Not loose but had some movement in it. I changed both clamps to the screw type as well as taking off all grounding points and sanding away any oxidation. to my surprise, the engine hasn't had a single stutter after this. I am hoping this has been the issue all along!

[Kristian27]

The car has been running without issue for around 1 week now

also, would anyone here know at what voltage Economy mode is triggered? I have a SilverCalcium battery that is only 1 year old now fully charged the battery a couple of days ago but still getting "Economy mode active" the second the engine is switched off, measured the battery voltage a few days after fully charging it and it was reading 12.4V.

[Hell Razor5543]

Economy mode is not usually triggered by voltage, but by a timer linked to how long the engine was running. If you have been out for a long drive economy mode normally kicks in after 30 minutes, but a short journey would result in a shorter period until economy mode kicks in. Economy mode is there to ensure you have enough power left in the battery to start the engine.

[Kristian27]

Economy mode is not usually triggered by voltage, but by a timer linked to how long the engine was running. If you have been out for a long drive economy mode normally kicks in after 30 minutes, but a short journey would result in a shorter period until economy mode kicks in. Economy mode is there to ensure you have enough power left in the battery to start the engine.

That's the issue, I can drive for 30 minutes but when the engine is switched off economy mode is immediately triggered

[GiveMeABreak]

The car has been running without issue for around 1 week now

also, would anyone here know at what voltage Economy mode is triggered? I have a SilverCalcium battery that is only 1 year old now fully charged the battery a couple of days ago but still getting "Economy mode active" the second the engine is switched off, measured the battery voltage a few days after fully charging it and it was reading 12.4V.

I'm not sure why you have a silver Calcium battery? They are not designed for these cars: "Silver calcium batteries generally require more charging voltage (14.4 to 14.8 V) and deteriorate rapidly in vehicles which do not provide the required voltage range. (Alternators) which never reach required voltage range will cause rapid sulfation due to battery never being charged fully. As a general rule, silver-calcium batteries should not be installed to vehicles or systems which are not specifically designed for silver calcium battery chemistry."

So I would consider getting a normal battery of at least the required specifications if not higher.

I'd check all your battery terminals, wiring and the earths. Make sure you have no accessories draining the battery. C5s will use power when not running to power the alarm and sensors if fitted, the 'wake up' circuit which waits for an unlocking request from the fobs etc., the suspension pump when the doors are opened etc., so there is power consumption. This cold weather will take its toll on car batteries as everything freezes, so always get as good a battery as you can afford when replacing it.

[Kristian27]

The car has been running without issue for around 1 week now

also, would anyone here know at what voltage Economy mode is triggered? I have a SilverCalcium battery that is only 1 year old now fully charged the battery a couple of days ago but still getting "Economy mode active" the second the engine is switched off, measured the battery voltage a few days after fully charging it and it was reading 12.4V.

I'm not sure why you have a silver Calcium battery? They are not designed for these cars: "Silver calcium batteries generally require more charging voltage (14.4 to 14.8 V) and deteriorate rapidly in vehicles which do not provide the required voltage range. (Alternators) which never reach required voltage range will cause rapid sulfation due to battery never being charged fully. As a general rule, silver-calcium batteries should not be installed to vehicles or systems which are not specifically designed for silver calcium battery chemistry."

So I would consider getting a normal battery of at least the required specifications if not higher.

I'd check all your battery terminals, wiring and the earths. Make sure you have no accessories draining the battery. C5s will use power when not running to power the alarm and sensors if fitted, the 'wake up' circuit which waits for an unlocking request from the fobs etc., the suspension pump when the doors are opened etc., so there is power consumption. This cold weather will take its toll on car batteries as everything freezes, so always get as good a battery as you can afford when replacing it.

Hi ! thanks, found the issue also got a regular battery but that was not the cause. turns out that for the entire time i have had the car the BSI has been in factory mode.. i always found it odd that the signal lights didnt come on when locking/unlocking and why i had a button on the fob with no function. fiddled around with lexia and was promted to put the bsi into operating mode, and no more economy mode

[Kristian27]

But one thing i am still stuck on is deleting the fault codes on the Injection system. I get the After-sales zone stuff prompting me to put in the milage, then it starts deleting then gives a communication error. have tried with engine on and engine off

[GiveMeABreak]

But if there are permanent faults, they can't be magically deleted - they will return as soon as the ignition or the engine is started depending on the fault.

Re-run the Global test again and allow it to fully complete, then post up what the remaining faults are.

[Kristian27]

But if there are permanent faults, they can't be magically deleted - they will return as soon as the ignition or the engine is started depending on the fault.

Re-run the Global test again and allow it to fully complete, then post up what the remaining faults are.

hi again sorry for the late reply, totally forgot about this I found that even though it gives a com error it seems to delete the fault codes.. seems strange .. but I have a permanent fault on "mid fan speed" I think it was.

video showing the issue
https://www.dropbox.com/s/1lecbmegrkogs ... 7.mp4?dl=0

[GiveMeABreak]

No problem better late than never!

That video seems to indicate a few possibilities: Is your VCI kit a full chip CAN compatible unit? If not, some Chinese clones can cause communications problems if they don't have all the hardware components on the circuit board (missing certain resistors and optocouplers). That's way some of the cheaper units are cheaper as they are cut down versions.

Secondly is the battery fully charged - if the system is going into energy saving mode during diagnostics it can cause issues.

[Kristian27]

No problem better late than never!

That video seems to indicate a few possibilities: Is your VCI kit a full chip CAN compatible unit? If not, some Chinese clones can cause communications problems if they don't have all the hardware components on the circuit board (missing certain resistors and optocouplers). That's way some of the cheaper units are cheaper as they are cut down versions.

Secondly is the battery fully charged - if the system is going into energy saving mode during diagnostics it can cause issues.

Hi again, got the Lexia Kit from Easy diagnostic UK so that should be fine ? battery is completely new and charged.
asked EasydiagUK for tips, they suggested i try diagbox 7.57 instead of v9 so will try that tomorrow and see how it goes