Citroen C5 2.0 Hdi Vtr 136 (Fap) Excessive Fuel Consumption

[paul.h]

Try your finger inside the tail pipe, should come out clean if the dpf is there - at least on our Citroens with a dpf you can see the metal is clean but that was around 50k miles.

 

With a diagnostic check the pressure drop over the dpf would be shown and if high that would indicate if the dpf was blocking up. You might also get a warning message on the car.

 

If anyone has any experience to share of the fuel consumption dropping after replacing a dpf it would be appreciated.

[adpace8]

Filled up the car with Total fuel today. I averaged 40MPG which was the same as last time. So it appears that i am regularly getting this figure.

 

I also checked the tailpipe and it is caked in black soot, i had quite alot on my finger and some on my hand. I could also feel a thick layer of the soot inside the tailpipe. So either the DPF has been removed, blanked off or is blocked and needs changing.

[paul.h]

The dpf could be bad news, try contacting the previous owner to see what has been done. Possibly it has been internally knocked through and maybe the ecu software changed so that the eolys fluid is no longer being dosed and warning messages being given. Possibly this was done instead of topping up the eolys at 80k miles. From February 2014 this practice was illegal for road going cars and if detected it would fail the MOT as well as insurance companies not covering the car due to a modification that would not pass the MOT. However, if the dpf has only had its insides knocked/drilled through and externally it has not changed, then it would probably still visually pass the MOT. If you got the car from a dealer/trader then you would have a claim against them if this has been done.

 

If the above has been done, then to get the car back to standard would need a new dpf fitting, the eolys topping up and the software putting back. The dpf will not have been blanked off or be blocked since the exhaust gases have to go through it and warning messages are normally given if the dpf blocks up.

 

If it is the dpf that is causing the poor fuel economy and the above has been done, your options may be to look at the cost (at a guess £500) for getting the dpf system working to improve the mpg or do nothing and accept the reduced fuel economy which could be overall cheaper. If you can not get any info from the previous owner, you may be able to see the eolys fluid level in its tank but you could also remove the dpf to see if it is internally in one piece and whilst it is off water jet it to remove any ash that could be blocking it, then put it back and see if the economy improves.

[adpace8]

Hi all,

 

Been a while since my last post regarding my issue, but I have been doing some digging around in an attempt to find out if the DPF has been removed or blocked off.

 

I was unable to contact the previous owner and the dealer I purchased the car from was no help either. So in a last ditch attempt to find out the problem  I took the car to my local Citroen garage who performed a diagnostic and the results were surprising.

 

They have told that the DPF is fine and does not require changing, I was also told that it is not regenerating correctly. They informed me that the cause of this (according to the diagnostic equipment) is the glow plugs, 2 of which are completely faulty. Also the Coolant temperature sensor is not working correctly. This fault was not found by Citroen but by myself as I have noticed since yesterday that the engine is being overcooled when in motion but maintains the correct temperature when stationary which rules out the thermostat and can only be the sensor. All of these would explain my excessive fuel consumption.

 

I have brought 4 new plugs and the sensor.

 

Now I know that the plugs are located at the back of the engine below the EGR Valve and cooler pipe and above the turbo. Access is not great at all and they cannot be seen without the aid of a mirror.

 

I was wondering if there was an easier way of removing and refitting the plugs?

 

Access from below doesn't seem possible due the turbo, pre cat and various of things in the way.

 

Any advice would be welcomed.

 

Thanks guys.

 

[paul.h]

'the engine is being overcooled when in motion but maintains the correct temperature when stationary which rules out the thermostat and can only be the sensor'

 

This to me means the thermostat is faulty since it should be closing a bit to reduce the coolant flow to the radiator when moving so the engine temperature is kept constant. It is probably opening early or too much. A new thermostat can be faulty, I had this once on a Saab. For the sensor to be causing this it would need to be switching the fan(s) on when moving but off when stationary.

[adpace8]

Been a while since my last post regarding this issue but i have now found the problem.

 

I had to use sat nav to get somewhere recently and noticed that the speed on the sat nav was different to the one being displayed on the speedometer in the car. The speedo in the car was under reading be 9 mph. Which meant that when i was doing 70 on the speedo i was in reality doing 79mph. As i mentioned in an earlier post i usually do 75mph which meant i was doing 84mph. After discovering this i started using the cruise control at 70 and in urban environments not exceed 2,000 rpm before changing gear and my fuel consumption was 47mpg.

 

To correct the speedo i had the system tested using a snap on diagnostic tool which confirmed it was out of sync. The needle had dropped off zero, it was put back on zero and re calibrated and was fine for a week and then dropped again. It was again looked at and the reason it keeps dropping was found. The stepper motor spindle has worn down and is not keeping the needle on zero. So i need a replacement motor or clocks. I can get clocks cheaper than a motor so will do that. Which brings me on to my next question.

 

Is the mileage stored on the clock unit curcuit board or the ECU?

 

I had read some where that if you replace the clocks it will revert to the highest value found on the clocks. E.g ECU shows 113,522k but clocks show 179,865 the clock will round and show 180k. If this correct?

 

Any advice would be very welcomed.

 

Thanks.

[paul.h]

An interesting end to your problem, lucky you did not get caught speeding anywhere. The speedo needle coming loose is a common problem. http://www.citroen-owners-club.co.uk/citroen/topic/15043-speedometer-repairs/

 

The needle on our C5 came loose due to a split in its collar and I simply put it back with a bit of glue and it has been ok since. A runny glue was needed and I had some wood glue which worked. To get it in the right position I did it with the instrument cluster connected and the ignition switched on since this moves the speedo motor to 0 mph.

 

The mileage is stored on both the instrument cluster and ecu so if you fit a replacement cluster from another car the ecu and cluster will go to the highest value between them. If you do this and get a replacement with more miles than your existing, you may need to take photos or keep another record since your insurance will have a mileage limit and could cause a problem if you need to claim.

[adpace8]

I know. Just goes to show that many of the cameras must be turned off following budget cuts.

 

Unfortunately glue didnt not work as the spindle which holds the needle is sheared.

 

I have been looking around for a replacement set of clocks with less mileage than mine but none of the breakers yards have recorded the mileage before removing them and do not know, which is frustrating.

I did phone Citroen but the price was simply out of this world £559.95+VAT! Got 2 on the shelf i was told by the guy on the phone. They will stay there forever at that price.

 

I would like to thank everyone for there responses and assistance in helping me with my issue.

 

In the meantime, if anyone on here happens to come across a set of clocks showing less than 114,000 on them, would you please contact me. Thanks.

[MikeLane]

I've noticed that wind direction and strength has a large effect on mpg. Travelling into a strong headwind from Calais to Rouen my indicated mpg was 47mpg. Then wind direction changed and strength dropped and, 350 miles later mpg indicated 57mpg. Actuel fuel usage turned out to be just over 12 miles/litre (about 55mpg).

(Where possible I use cruise control - especially in 30 mph areas and 30, 44, 56 and 69 in France where the police are alleged to penalise people exceeding speed limits by 1kph!)

Edited May 11, 2016 by MikeLane