Citroen C5 HDi Diesel/Smoking/Rough Running

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Sherrie E
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Citroen C5 HDi Diesel/Smoking/Rough Running

Post by Sherrie E »

We have a 2005 C% saloon which safe for 1 or 2 small problems, has been one of the nicest cars we have had, very reliable and so clean that during its first MOT the tester thought his machine was faulty because of such low readings. However following a rear end shunt 2 years ago, which made a mess of the car that hit us, left our car quite undamaged thanks to the tow ball. Unfortunately ever since the very sweet running has gone. The car smokes badly from cold starting-the worse the colder the weather- and runs very roughly until it reaches working temperature. Then it runs reasonably well but the exhaust smells acrid, which was never the case.
Various main dealers have changed the fuel injectors, EGR valve, glow plugs and checked valve timing at ruinous cost and achieved nothing. Even more money was charged by a so-called expert who had no clue what the problem was but charged us money for it.
Although when warm, the engine runs OK it would stop rather dangerously in traffic and then after a short pause start up and run OK for weeks. Since having an EGR blanking plate fitted, there is still much smoke but running is improved and the stalling in traffic no longer happens.
We like this car and want to keep it a bit longer but we are now desperate to get this problem fixed. Can anyone help with advice as to how a rear end shunt could have caused this problem?
Thanks
Sherrie E
jgra1
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by jgra1 »

Where are you sherrie? I think a free diagnostic session from a nearby member may help.. I personally can't see how a rear shunt could cause rough running but..
Stranger things have happened :)
John

edit , sorry just seen you are in Ongar (viewed the post from my phone which doesn't show the location)
Bick
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by Bick »

Really daft question, did the rear end shunt damage the exhaust in any way?
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myglaren
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by myglaren »

Welcome Sherrie.

As John has said, if you contact one of our members who own the proper diagnostic tool (Lexia) they will run a diagnostic session for you that may help to pinpoint the problem.
Most only make a very modest charge for this service.

Contact them by PM to arrange a time and location.

All members who offer this service are listed here: Lexia Locations
Your closest one is in Chelmsford.
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Stickyfinger
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by Stickyfinger »

Or take a day trip round the M25 ?
http://www.blautos.co.uk/index.html
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myglaren
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by myglaren »

^True, if they can't fix it no-one can.
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Stickyfinger
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by Stickyfinger »

and not that far from Ongar either for it to be the "local" garage for the car.
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by wurlycorner »

Hi Sherrie,

Sorry to hear of your woes :(

I'm in Chelmsford and wouldn't dream of charging for a Lexia session :-)

I'll be honest though, that while I can drive Lexia ok, I am not an expert on that engine - so I can tell you what Lexia shows (what faults logged etc and from when) and also run through any actuator tests, but when it comes to watching live readings from engine sensors, I wouldn't know what is normal and what is out of spec (and by how much). I can always take screen prints and post on the forum though, that others can then digest later...
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by wurlycorner »

Ok they brought the car round to me today and I was happy to be able to check it over with Lexia.
It's a 2.0 HPi (138bhp) rather than a 1.6.
Unfortunately nothing jumped out in terms of logged faults.
The Injection ECU did have some logged faults;
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I went in to check some of the parameters. I don't know what's 'normal' on this engine and what isn't, so some screen dumps for other people to check over please and see if anything looks out of spec;
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Annoyingly I couldn't even easily compare things against my 2.0 HDi 110bhp, 'cause the parameters shown (and the units used) are different. e.g. on mine the injector flow control is in actual flow rate, whereas on the HPi it's in % :evil:

So, nothing jumped out there to me - maybe someone else can spot something.

Interrogating the fault log though, was potentially more interesting?
3 faults that are 'not listed'
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And another that is apparently an 'engine torque' fault, but logged in the ABS ECU???
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The 'not listed' and 'engine torque' faults are the most recent ones;
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So I went into the ABS ECU to look at the torque fault;
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So there we go...
Any thoughts anyone?

The only thing that's occurred to me is that the engine has an EGR blanking plate fitted and I seem to recall reading on here that if that's done, you need to disable the EGR in the ECU. As it's logged a fault, I guess that hasn't been done???

What is the coolant bypass valve that has a fault logged? What does that do and is that relevant?


One other thing of note is that it was incredibly sluggish updating the live values on the laptop. It would take something like 7 seconds to change the readings when altering the throttle;
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That was from around 2500rpm, throttle lifted to idle at 2 seconds in, displayed values didn't react until 12 seconds in.

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Gently revving it up/down. No reaction.

I thought maybe it was the laptop playing up but straight after I went over to my C5 to check immediately afterwards and it was reacting as it should;
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Whether that's relevant or not, I don't know?

Anyone have any thoughts?
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GiveMeABreak
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by GiveMeABreak »

The first thing that stuck out to me Iain was the particulate filter is almost completely full of soot. At this level of blockage, regeneration is likely to be impossible and the DPF would likely need replacing / properly cleaned out and the additive topped up. (I note a slight typo as you've referred to it as an HPi petrol at the top of your notes , but it should be an HDi Diesel) :wink:

Here is an extract explaining this - and with Sherrie's C5 soot level readings at nearly 97% it is way past the regeneration stage according to these guys:
Forced regeneration
Forced regeneration is required where `Active` regeneration criteria have not been met or where soot levels have increased within the DPF to a point where normal regeneration cannot be performed: typically around 70% soot loading. At this point the vehicle will enter a 'restricted performance' mode to prevent further damage. If left the soot loading will keep rising.

At this level of soot loading a diagnostic tool must be used to force regeneration. Above around 85% soot loading regeneration can no longer be performed on the vehicle and the DPF will need removing to be cleaned or replaced.
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by wurlycorner »

I thought I'd commonly seen HPi rather than HDi used to differentiate between the HDi engines with and without particulate filter?

Interesting... Where are you picking up that the filter is clogged?
Based on these readings, I'd taken it to be ok?
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(only "35% soot" and "filter in correct state")
What am I missing?
(I now note that it also says regeneration is impossible! But why?)


EDIT: ah, interesting... 97% soot load, in the first screens.
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So... what's the difference between soot load and actual soot?

Surely %soot clogging is the amount of actual soot in the filter?
Is soot load the balance of flow it sees across the filter?
Or the amount of soot being passed into the filter?

Does that suggest the filter itself isn't blocked, but perhaps the pipework to it, is???
Or am I misunderstanding what soot clogging is?

And why hasn't it logged a particulate filter fault, if there is a problem there?


I think they were told by a garage that the particulate filter had been changed?
Last edited by wurlycorner on 30 Jan 2016, 17:59, edited 1 time in total.
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GiveMeABreak
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by GiveMeABreak »

Hi Iain, the HPi is the PSA High-Pressure Direct-Injection Petrol engine featuring lean-burn stratified-charge technology.
On the 6th screenshot down - SOOT LOADING 96.86%. :wink: It also states on this shot that the 'Driving Type' is Severe (Town Driving), which indicates that the car is not getting hot enough to start a regeneration cycle. Too many short trips typically and not good for the DPF. If this driving style is maintained without a good long run frequently, the filter will just keep getting fuller and fuller of soot. Once it reaches these high levels, there is usually no option other than to have it replaced.
Short story, don't get a diesel with a DPF if you only use it to nip to the shops and back. It will end up costing you more in the long run.
Last edited by GiveMeABreak on 30 Jan 2016, 18:02, edited 1 time in total.
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by wurlycorner »

GiveMeABreak wrote:Hi Iain, the HPi is the PSA High-Pressure Direct-Injection Petrol engine featuring lean-burn stratified-charge technology.
Ah fair do's. I must have seen it misused then.

Anyway;
On the 6th screenshot down - SOOT LOADING 96.86%. :wink:
Yep, see above - that conflicts with a low filter soot clogging % reading though, does it not?
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by GiveMeABreak »

Just edited previous post to add a bit more info - but I've dug this technical article extract out, which talks about the issues of correct measurements:
Efficient after treatment management requires accurate sensing of both particulate filter soot and ash levels for optimised feedback control. Currently a combination of pressure drop measurements and predictive models are used to indirectly estimate the loading state of the filter. Accurate determination of filter soot loading levels is challenging under certain operating conditions, particularly following partial regeneration events and at low flow rate (idle) conditions.
So it would seem that the load state may not be accurate, but given the 'severe' town driving warning and the soot levels, I would hedge my bet on the filter being blocked and would partly explain the poor performance.
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white exec
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Re: Citroen C5 HDi Diesel/Smoking/Rough Running

Post by white exec »

Worth a hot, fast motorway blast before the soot builds up any further.
And maybe avoid supermarket diesel?
Just a thought...