C5 Hdi Irratic Loss Of Power When Engine Hot.

[John.A.S.]

Hi,

I have a C5 2L HDI (2006) engine number BW10TED4.

The car ran well when I bought it but never reached normal engine temperature. As winter was approaching I decided it was time for a new thermostat. That's when the problem started.

Car ran fine for around 7 miles (until the temp gauge got up to around normal) then setting of from the lights the car would start to pick up and then hesitate for a second, then pick up as normal, if you accelerate slowly its ok but normal acceleration would cause the same dip in power. If traveling at a constant speed and it starts to loose power ( only for a split second or so) either easing off slightly or increasing power slightly sorts the problem for a short while. If you put your foot down hard it would fly but left a dense cloud of black smoke behind.

I tried changing all the filters (Citroen filters used). But did find small shreds of metal in the fuel filter. So a new HP pump was fitted (no lift pump in the tank).

 

Citroen diagnostics said it was the EGR control valve and the supplied the unit that sits on the rear left of the engine, it supplies a vacuum to the turbo. The EGR valve on my car is at the rear right of the engine and is electronic.

 

I removed the EGR valve which looked newish, smooth in operation, and a good valve seal. No vacuum pipe on mine its electronic. Checked round all the vacuum pipes etc and could not find anything amiss.

Took it for a run and I had lost turbo. Checked over all the connectors and found one that looked connected but had not clicked in.

Took it for a run, turbo is back, no black smoke, but lacks a bit punch. It has run fine all summer, just a bit short on kick when you want to overtake but turbo is working..

 

The first frosty morning and we are back to the original problem OK when cold, when engine at operating power - momentary loss of power when setting off, accelerating, and cruising at around 65mph.But no black smoke.

It feels like the fuel supply is turned of for a second and then back on.

It seems to be temperature related.

The EGR valve I am told only operates when the engine is at operating temp. Also I have two pipes from the turbo to the inlet manifold. One direct from turbo to manifold ( when engine cold ) The other pipe turbo - cooler- manifold (engine hot).

I am using diesel from a BP garage.

Anyone any suggestions as to what is causing the hesitation.

Thank you for your time.

John

[ivorcitroen]

When i clicked on the favourites button to come on this website tonight instead of going to the homepage this came up.

C5 2005 2.0L 136Hp Diesel Hesitation, Help Please!

Which although is not exactly the same problem but simular

I have the same engine and the same hesitation( but not temp related) also i know someone with a peugeot 307 same engine same hesitation although i don't think temp related. .

the post above appeared on here in march 2013 i think. 

[John.A.S.]

Hi, I know it seems odd, but the problem only started after the thermostat was changed. I can do short runs with no problem, but after around 5 miles the temp starts to rise and then then as the temp starts to reach normal the problem starts.

I wondered if the air intake flaps from the turbo were sticking as now with the cold mornings the turbo - cooler - manifold flap would be closed and start to open as the engine reached normal operating temperature. If its not working as it should it could be causing momentary air restriction, which I think would cause a cut in fuel. I think the flaps are vacuum controlled so it could be a vacuum problem. Perhaps as the pump warms up it is failing in some way. Just grasping at straws to as certain extent.

[paul.h]

Welcome to the forum.

 

I am not sure about this, but the air flow meter measures the temperature of the air going to the engine so maybe this has a fault but not bad enough for the engine malfunction light, but enough to affect the fuel/air ratio. The other temperature measurement is the coolant, I think on the left end of the cylinder head, maybe this has a fault.

 

However, it is also possible the new thermostat is faulty - I had this once after replacing one. A code reader that gives live data so you can see these 2 temperatures would be useful and you could check the temp at which the thermostat opens. 5 miles seems a bit far for the temp to start rising, 2 should be enough to get close to normal temp.

 

If you think it is the egr valve and you have a replacement or the old one, you could try plugging the connector to the spare which would stop the installed one opening but let the car think one is installed - then it should be as though the egr valve has been blanked off.

[qman3428]

John A S, I think you will save money in the long run by getting a diagnostic check done

 

Ivorcitroen, try changing the fuel filter as they clog easily and the first sign is hesitation.

[paul.h]

There is an article on the BBC news site today saying that since the amount of bio-fuel has increased in diesel, in colder weather, the fuel filters are blocking up more leading to sudden power loss. Due to some rules, the amount of bio-fuel has to increase each year and now averages about 5% - so could be more in some areas. http://www.bbc.co.uk/news/business-25321913

[ivorcitroen]

thanks to qman 3428 iv'e recently done the filter didn't make any difference.

Bought a c5 in kent once and drove it to the north east,it ran ok until you overtook or went up a hill then used to splutter till you released the pedal a bit.

got home next day took fuel filter out,never ever seen one so black.

John.A.S you could always test the stat the old way (a pan of water on top of the gas)

[paul.h]

John.A.S - do you keep your car in a garage overnight. It may not be relevant but if so it would be warmish on starting up (like summer conditions) but then once out in the cold the fuel etc would cool down. Just thinking about the BBC report - it may be worth trying fuel from a different supplier than BP in case their bio-diesel level is high.

 

How many miles has the car done ?

[John.A.S.]

Hi, At the moment it sleeps on the drive as the garage is full of kitchen units. I am doing a kitchen refit and Christmas is looming.

Car been on drive all day, went to B&Q this evening, thermostat working as it should, hot air blowing at a mile, temp gauge starts to rise at 2 miles, gauge just coming up to normal as I arrived at B&Q. On the way back temp gauge reached normal on approach to roundabout, and the engine hesitated at take off from roundabout. My wife says it does not do it when she drives, so I thought I will drive as she does, lots of revs at take of and very much foot down and ease off, Driving hard it seldom happens, but I am far more casual and gentle on the accelerator. Fuel consumption average running round 40mpg,  touring at 55-65 mph 60mpg. Motorway at 70 - 55mpg.

The thermostat on mine is a sealed unit about 12 inch long and cost around the £65.

 

We do not have a good Citroen or diesel garage in Preston. But I do have a garage nearby who claim to be a Peugeot specialist and he charges £25 to read the cars brain. So will start with that. Will also call at a dealership in Eccleston who supply my bits and bobs as cheap as I can get them from the motor factors and get a new fuel and air filter. Then go all round the pipes again.

 

Still can't help feeling that the temp reaching normal caused the ECU to switch something on or off that's causing the problem.

 

On a side note, On many forums I have read about people having an annoying rattle on the front end when on rough road surfaces cobbles etc but not on things like road humps as I did. I checked every thing and never found the cause until last month I put new discs and pads on the car supplied by my friendly dealership. The pads that came out looked just like the Citroen ones I put in except for one thing the Citroen pads have a rubber coating on the back of them, I asked why when I got them, They said it prevents that rattling noise you can get with some none Citroen pads. And he was right nice and quiet when on rough road surfaces.

[John.A.S.]

Sorry missed the last question, it's done 74000 miles. 

[paul.h]

Almost sounds a bit like turbo lag that can happen on some cars - turbo does not kick in until engine revs reach say 2000 rpm. However, I do not know if the C5 2.0 hdi is known to suffer from this, our C5 is a 2.2 hdi. Also a bit as if the accelerator pedal electrics are worn - the diagnostic could check for this or try slowly increasing the revs and seeing if they increase gradually as the pedal is pressed. Maybe when the engine is cold the fuel mix would be a bit richer so could mask another problem.

 

Engine management systems are supposed to adapt to driving styles so maybe a bsi reset might help - see what others have to say on this.

 

When I have cleaned our C5 front brakes, the pads (Citroen ones with the coating) have been stuck in by the dust at the ends in the calipers so would not be free enough to rattle. I always use copper grease on the back when refitting though to help prevent squeal. I did have a rattle on a C3 which was an anti roll bar drop link that had worn at the joints.

[John.A.S.]

Hi All,

I changed the air and fuel filter no change. So had a diagnostic check and was told EGR valve. So searched EGR valve causes and cures etc on Google and found an interesting article which said

EGR valve can cause hesitation on setting off and whilst cruising. The valve should be closed under positive acceleration. A good pointer to the EGR valve being the culprit is if the car drives normally for the first 10 minutes or so and then starts to play up. The reason for this is that the EGR valve only operates when the engine reaches "normal operating temperature".

I got a new valve from Ebay - £98 Delphi it was exactly the same as the old one I took off.

Car ran great for around 25 miles, then just as I got on the motorway it started to lose power I held it at 3000 revs and prayed but it was a definite loss of power not the same as previously. Then the depollution symbol came on the dash followed by the service light and the dreaded depollution system faulty appeared in the display. Then the car burst into life again and was fine. Service light went off.

As I had the depollution symbol on the dash and disconnecting the battery overnight did not clear it I hunted round for a garage that might be able to help (Saturday after Christmas day). Found a tatty place and the old gentleman said he would reset the system, so I asked him to clear all the fault codes etc, which he did and did not want any payment for it, but I did give him something.

He asked what had happened, I told him the story and he said it was probably the ECU regenerating the depollution filter. I mentioned that the turbo was softer when the engine was hot then cold and he said make sure I check and clean the air intake changeover flaps as the hot air one tend to get a build up of muck and often prevents it from fully opening.

I have done about 250 miles and not a flicker turbo is smooth and revs up to 4000 with ease if I don't watch it. It drives like it has never driven in the past but the turbo is definitely more positive when cold running so will check the air intake flaps when I get the chance. Hope this feedback helps someone.

[paul.h]

Thanks for the feedback. So the culprit was the egr valve after all. However, it looks as if the dpf system may be starting to be giving problems, at about 74k miles it may be due for the filter replacing/cleaning and the eolys fluid topping up.

[John.A.S.]

Hi, No eoyls on mine just a particulate filter. Which the book says if display says depollution fault drive normally at a steady speed until the display clears. The Citroen agent told me if the filter starts to block the ECU will adjust the timing and fuel so the engine runs hot and the hot exhaust gases will burn the residue off the filter. Still not sure which is right. I was told that at around 65k you should have a new one fitted. My local garage says they take them off and power wash them, dry them out and they are fine. So will wait to see if the DPF has regenerated if not will try the power wash. Thanks for your interest.

[coastline taxis]

It cant regenerate without eloys oil. it needs this to burn the soot out the filter

[John.A.S.]

Hi,

Mine is the 136bhp with particle filter But does not use the eloys oil system to clean the filter. Mine regenerates by advancing the timing and increasing the fuel, this creates very hot gases in the exhaust system which in turn burn all the deposits off the filter.

A mechanic at the Citroen dealership did say you can add a small amount of eloys manually when you fill up and it will help to keep the filter clean but he could not say how much per litre. I have found out that there is a specific additive designed to be added to the the fuel which will allow the deposits in the filter to burn off at a lower temperature.

But for the time being I will see how long the car keeps running so well. 

[paul.h]

It may be worth you doing some extra checks on the eolys fluid. It is in a small tank under the back of the car, also the fuel tank cap willl have a couple of magnets in it to tell the car when you fill up - if you remove the cap you will be able to see them. If not already done, check the parts diagrams using your vin on the service.citroen website - you will need to register as another professional, member of the Citroen Owners Club.

 

I thought the DW10TED4 engines on the mark 2 C5 were all 138 bhp.

[John.A.S.]

Hi, Sorry yes it is 138 bhp, I do have access to Citroen box online and no signs of the eloys system on the diagrams. Dealer confirmed mine is not eloys system and I double checked when I fitted a Citroen towbar. No container at the rear end for eloys. My vin VF7RCRHRH6734809.

They also do a 138bhp without a FAP. When I bought mine I was under the impression all 138bhp did not have a FAP but it turns out some models were fitted with them. 

[paul.h]

If you want to see the eolys system parts they are under engine/air and fuel supply/fuel tank fuel gauge. The vin you have given is a digit short, there should be 17 - if a 7 is added after the HRH it comes up with a C5 which fits your description but with an eolys system shown under fuel tank fuel gauge. The eolys tank is part 9 - additional fuel fuel additive.

[John.A.S.]

Hi, Yes you are right. When I had problems with the "depollution system faulty" being displayed they never mentioned the eloys system and when I queried it they said Citroen used two systems (a)eloys or (b) ECU increasing the fuel delivered along with advancing the timing creating very hot gases in the exhaust. They told me mine was (b).

I Have been on to them and now they say they are almost sure mine is in fact eloys.

I have not had any display saying eloys fluid low, but did read somewhere that some models of the C5 do not tell you when the fluid is low the ECU just generates a 'depollution system fault' in the display.

They told me to ring Monday when the boss is back in the chair, but have said they will check for the eloys system, fill the system, check it is working and reset the ECU counter for £190. But the boss may give me some discount as they did not mention the possibility that the fluid could have run out and I buy all my bits from them.

I know its around £100 for the fluid and approx. £35 to reset the ECU counter. They did say recommended top up was 75 to 80,000 and I am now on 75,000. Will be interesting to see if it has run out.

But if the fluid has not run out I could have a problem elsewhere.  

[John.A.S.]

Hi Moderator.

Found something interesting when looking on Citroen box under air and fuel system. I clicked on the diagnostics and my problem is listed under straight to the fault.  (For some reason I can't copy and paste the information for all to see). But it does say models manufactured between Oct 2005 and Jan 2006 had problems with the EGR valve sticking and causing all the problems I have been having. As my car was registered first registered in Sept 2006 their is a good chance mine is one of them.. Will see what the fix is when I go to the garage on Monday. John.

[coastline taxis]

 ( B) ECU increasing the fuel delivered along with advancing the timing creating very hot gases in the exhaust. They told me mine was ( B).

 

this sounds like a forced regeneration to me. Not recomended for a enginge that your having trouble with as the engine sits at high revs for 45 mins.  seen it done on a 1.6 that was having trouble and it blew the turbo

[qman3428]

John A S just so you know there is a brilliant Citroen dealer in Eccleston, suggest you get them to do a diagnostic. You will find them on the green.

[John.A.S.]

Hi, qman,

I am guessing  you mean Rigbye and Sons. I live in Preston less than a mile from Looker's but always go to Eccleston for my bits and advice, If you moan at the price of the parts you end up getting them a lot cheaper. I get my oil and filters from them cheaper than at the motor factors or Ebay.  Car is running great at the moment, I have even cured the annoying rattle on the front end after 12 months of trying to find it. I just need the ECU programming to "learn new part"  ECU.

There is an auto electrician just up the road from me and he cancelled my last faults at no charge. So will get him to connect his lexia up and programme the ecu I think. Thanks John. 

[paul.h]

As a reminder, what was the annoying rattle (please do not say it was a passenger) ?

 

On the more recent version of the Citroen service box, the fault finding section has been removed.