Hesitant Engine in my 2010 C5 1.6HDI

[johnmc5]

Hello.
I've just joined your Forum and this is my first post.

I've a 2010 Citroen C5 1.6HDI 110 BHP with approx 330,000 km on the clock. I spent quite a lot within the last 4 months on large ticket items incl a new steering rack, new clutch, new alternator, a new battery & Eolys fluid replacement and I dont want to have to replace the car for a while yet having spent so much on it. The car is usually driving ok but there is one issue that's concerning/puzzling me over the last 12 months or so and I was hoping that someone might be able to shed some light on the source.

When I'm driving, its as if the engine can momentarily loose some power and become hesitant in itself. Other words I'd use to describe it is a brief labouring or chucking/shunting lasting a fraction of a second. It generally clears itself if I drop down a gear and increase the revs. This can happen quite regularly, sometimes 3-4 times a day Its very subtle - as if your left foot is very lightly tipping the brake whilst the right foot is on the accelerator. It can happen in any gear - from 2nd up to 5th. If it happens as I'm cruising in a high gear, I sometimes notice a cyclical pattern to it. (until I drop the gear & give it welly).

I know v. little about engines but would it be something relating to fuel feed? I put it through a diagnostics check at the Citroen Garage. They could find nothing wrong apart from a fault showing on the electrical accelerator pedal. I got this replaced but it didn't solve the problem. I've also had the fuel filter replaced recently. Leaving the house for work this morning, the car conked out at the front gate. It eventually started again (fortunately I had a new battery fitted a couple of days ago!). On starting again this morning, an orange engine management light came on with a message appearing "Anti Pollution System Faulty". I've noticed this message & the fault light appearing at times over the last 12 months but it tends to go out again after a day or 2.

Can someone shed some light on this engine issue please - what I'd describe as an issue causing a subtle hesitancy in the cars forward motion that happens frequently. Would it cost much to resolve it??

Thanks. John

[GiveMeABreak]

To be honest John you need to have it diagnosed again. With this message on it should of triggered a stored fault that can be retrieved. Anti-pollution faults can be caused by several things, but without further info, and having ruled out the fuel filter which you have changed, it will be difficult to diagnose correctly.

It may be that given the mileage the vehicle has done (205k miles), there could be a lot of carbon / sludge build up in the intake manifolds, a sticking or clogged EGR valve etc.

You may want to try some diesel fuel system cleaner additive in the next few tankfuls and let that work it's way through (don't top up the fuel tank again until the tank is low, or you will dilute the effects of the additive). This should clean the injectors and fuel system.

Another thing could be the DPF starting to block or limit performance - it has gone well over its service life at this mileage and I'm surprised you have not yet had a warning about this.

[johnmc5]

Thanks Marc.
I have the car about 10 yrs now and have filled up the Eolys fluid twice over this time (most recently about 3 months ago) - each time being prompted by a message that appeared "Particle Filter additive level too low". I often buy Dipetane and add it to the fuel tank when filling. My mechanic ran it through a diagnostic test yesterday. It didnt show any fault with the EGR valve but it did show I have a couple of glow plugs not working apparently and some fault or other with a rail pressure sensor??. I was about to spend money on a replacement EGR valve but I think I'll get the glow plugs sorted first and see if that helps. Maybe I should also consider getting both the EGR valve & DPF cleaned out. What do you think? I understand (from looking at YouTube videos) that cleaning out the EGR valve is relatively straight forward but that removing the DPF takes more time.
Thanks again. John

[GiveMeABreak]

The clue there is in that last bit of new info - Rail pressure! That will be referring to the fuel rail pressure sensor. The engine management ECU checks the pressure of the diesel fuel in the fuel high pressure common injection rail in a closed loop via the fuel pressure sensor. If this is faulty then it can of course affect the info being sent to the engine ECU which will affect the other components in the fuel system.

Is your mechanic using Diagbox to diagnose the vehicle? If not he may be missing faults that his scanner won't pick up. For fuel rail issues the following are possible faults. All these can cause jerking / stalling or lack of power. So may be worth ensuring you get a diagnostic done with Diagbox so you are not missing key faults. Replacing parts is not going to help if the root cause is not correctly identified.

This is the high pressure common rail

(12) is the high pressure fuel sensor
'K' is the high pressure fuel supply.

These are some fault codes that may be stored concerning the fuel pressure:

P0087: High pressure fuel regulation - The measured rail pressure is too low in relation to the set point
P0088: High pressure fuel regulation - The measured rail pressure is too high in relation to the set point
P0192: Fuel pressure signal - Short circuit to earth
P0193: Fuel pressure signal - Open circuit or short circuit to the plus

[myglaren]

May be worth knowing that the glow plugs can be a nightmare to remove on the 1.6. As they are rarely used it may not be worth pursuing.
If at first they don't come out, forget them.

[Paul-R]

A motto for life.

If at first you don't succeed - give up.

[admiral51]

May or may not be helpful but has the Turbo Solenoid Valve been cleaned/replaced ?
Stuttering/flat spot were issues i had years back on 1.6.

Have a look at viewtopic.php?p=583548#p583548

Not my 1.6 but very good info

Colin

[johnmc5]

@Colin - Thanks for that
My God! - After reading that article - viewtopic.php?p=583548#p583548
I think I'll get myself a bicycle
John