C5 engine hesitation when engine warm

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johnsumner
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C5 engine hesitation when engine warm

Post by johnsumner »

Hi all,
I have a C5 VTR 2ltr Hdi 138bhp, 2006. Vin VF7**************[VIN obfuscated, can be read by forum staff] (10063) First Reg Sept 2006.
History-
Shortly after buying the car winter came along and the heater was not getting up to temperature so a new thermostat unit was fitted. Then the problems started.
When the engine reached operating temperature the car would hesitate when moving of from stand still and when cruising you often got small drops in power for just a second or so. The car was fine when engine cold, also OK when driven hard.
Citroen dealer diagnosed turbo electronic control valve to be the problem. I changed it with no effect. They then said the it must be the pipe from the valve to the turbo, changed it with no effect.
I knew the EGR valve (electronic on mine) only comes into use when the engine reaches operating temperature and only opens when the engine is not under load (cruising). So I removed the EGR and it was surprisingly clean and looked fine. When I refitted it the problem went but the car was lacking in power a little I thought. Ran fine all summer, first frost the problem is back.
I fitted a new EGR valve over Christmas and it was like a new car bags of power and free revving etc until I went on the motorway and held it at 3000 revs to give the engine a clean out, After about a mile the engine closed down, service light on, depollution symbol lights up and depollution system fault in the display. It continued to lose power and fire up several time.
I stopped switched off and started up again all was ok running well again. I had system reset to clear the lights and its run fine since. But just occasionally it feels as if it's going to hesitate on setting off.
So I decided to look at the Eolys system on Citroen box under "air and fuel supply", and for some reason pressed diagnosis not expecting to see anything .
The following appeared-

Straight to the fault, Hesitations at low engine speeds (between 1500 and 2500 rpm and under light load) linked to the operation of the exhaust gas recycling (EGR) valve for vehicles manufactured between October 2005 and January 2006, the EGR valve can become jammed in the open position, causing failure to start or even cutting out while the vehicle is being driven Lighting of the engine diagnosis warning lamp / message "depollution system anomaly" on the multifunction display. Engine hesitation at low engine speed (1500 to 2500 rpm) and low load linked with the operation of the exhaust gas recirculation solenoid valve. Total lack of power while driving resulting in stopping of the vehicle ; the engine continues to run at idle until it is switched off ; when starting a warm engine normal operation

The system would not let me see any further information. This is the problem I have had off and on for 2 years. I have checked pipes connections, airways etc many times and found nothing.

I showed the Citroen dealer and asked if they check to see if it included my vehicle and what the fix was. No he said we always start with a basic diagnosis and see what faults are recorded in the cars log and proceed from there. I said if there are not fault codes what then. He said in that case the car does not have any problems!!!
Citroen have themselves highlighted a problem in the diagnosis list and will surely have listed a fix. was I asking too much of the dealership?
So I am still no wiser as to whether it applies to my car or not.
Can anyone help.

Thanks
John.
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Re: C5 engine hesitation when engine warm

Post by RichardW »

Hi John

Welcome along!

Not a common problem we have seen before - I looked up the VIN of your car, and it reports a build date of 23/01/06 - so you would be within the window of that bulletin. No idea what is wrong with it, it doesn't suggest any solution - the obvious one (new EGR valve) has been done.... Unless it's an ECU fault 8-[
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Re: C5 engine hesitation when engine warm

Post by jgra1 »

John.. worth noting that the faults log and logged current faults are seemingly different.. when i saw my log recently, it had thousands of entries (a lot from a non de-iceing mirror to be fair).. a lexia clone (and a laptop) will diagnose the car and cost about the same as a trip to dealer for a fault clearing session.. john

Apologies if thats no use or you already have a lexia..
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Re: C5 engine hesitation when engine warm

Post by dnsey »

I wonder what would happen if you were to temporarily disable the EGR valve.
It might at least confirm where the problem lies (or not).
johnsumner
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Re: C5 engine hesitation when engine warm

Post by johnsumner »

Many thanks Gents,

This time it looks like I have picked a sensible Citroen forum.

Richard; If I put C5 engine hesitation into Google quite a few people seem to be experiencing the same problem. Hesitation on moving off and little dips in power when cursing the later not being a big problem, I just ease off a bit or increase speed a tad then back off and it's OK for a while.
Why do Citroen highlight a problem then do not list a repair. Perhaps they used a different manufacturer of EGR for that batch of cars and replacing the EGR did away with the problem. Thanks for checking.

jra1: I did not know a lexia clone was available probably worth a go. Is the clone a read only device. Last time the system was checked with a lexia at Christmas I told the guy to clear everything. So only current faults should be available. You can display alerts on the cars display but the only thing that is ever in there is depollution fault. At the moment it displays nothing.

dnesey: This has been done by someone and the fault went away. but it did throw up faults and these had to be cleared by lexia when the EGR valve was reconnected.

The dealer said it may just need the new EGR programming into the ECU but he was not sure if it did require doing, I know sometimes new parts do require an ECU setup. But never heard that a new EGR needs programming in but if they did use a different manufacturer for the original EGR valve he could be right. The valve I took off was a delphi and was identical to the one I put on.

The only cure for the fault I have come across is a new download of the current software which cured the problem in one case I read about. So yes could be the ECU or its software.

The car has only faltered once since the new EGR was fitted and I have done 300 miles since then and it is running well.
I am also using BP diesel at the moment which always improves the running, usually alternate between BP and Sainsbury's. Put ASDA's in a couple of times and it ran like a three legged donkey.

The dealer did say they were getting info from Citroen that fuel filters are causing some problems since the increased amount of bio fuel now being used in diesel. I changed all my filters a couple of months ago and I noticed the fuel filter was dirty.

I am in Preston Lancashire, If you know of any good Citroen or diesel garages in my area please let me know.

Thanks

John.
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Re: C5 engine hesitation when engine warm

Post by myglaren »

John, one thing you may not yet be aware of is that a lot of our members own Lexia clones and offer to run diagnostics sessions for other members for a very low fee compared to the dealers - this is something to be agreed between you and whomever agrees to run the diagnostic.

The nearest to you is trainman. He is currently pretty short of time and may not be able to help but there are others reasonably close to you.

To contact them, check this thread then look the appropriate member up in the members list and PM them. Not that there is a map there to make locating them simpler - the map can take a moment or two to load!


The Lexia is Citroen dedicated and can run a huge array of tests, clear fault codes and tweak user settings that cannot be accessed any other way. Almost magic.
johnsumner
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Re: C5 engine hesitation when engine warm

Post by johnsumner »

Hi myglaren,

Just found this on a Peugeot forum for HDI engine. Replying to someone who had fitted a new EGR and was still having problems.

When you fitted the new EGR, did you tell the car it had a new one with PP or Diagbox so it can re-learn
read that somewhere but looked everywhere in PP but couldn't find any reference to "Re-learn" the EGR. Any pointers on where to look.
No idea about PP as I use Diagbox, but on Diagbox you go into the ECU and there's an option for New bits (forget what it's called) and then EGR is listed.

Is this something the lexia is capable of doing. If a Peugeot ECU needs to be told it has a new ECU then its a safe bet a Citroen does.

Moving forward slowly.
John.
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