C5 intermittent power loss

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Galmac
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C5 intermittent power loss

Post by Galmac »

I hope someone has had a similar experience and can help me diagnose a fault with my car (apologies if this has been asked before - I did try searching and couldn't find a similar thread). I have a 59 plate C5 1.6 HDI VTR+ Nav (diesel) and every now and then when driving the revs drop for a second. It is sporadic, sometimes it'll go a week without doing it, sometimes it will do it on consecutive trips. The best way I can explain it, is It feel like you are driving and you have taken your foot off the accelerator for a second and then reapplied it (just for clarity the revs drop not increase so I'm pretty sure its not the clutch). There is a noticeable drop in revs on the tachometer, but it lasts for about a second and then goes back to normal. It tends to happen when I am cruising/maintaining a constant speed and RPM, usually between 1500-2000RPM. I had the main dealer look for error codes when it had its most recent service and there were none, and then a month or so ago at in independent garage who specialise in French cars and they could not replicate the fault and there were no error codes. I have noticed that every time the fault occurs, when I turn the car off the engine fan is running, even though the temperature gauges are all normal and not showing any overheating (I'm not sure if this is related but it seems to happen too often to be a coincidence). If anyone has experienced this fault before and has any solutions it will be much appreciated!
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Re: C5 intermittent power loss

Post by Jeff »

Dont know about fan but power loss symptoms similar to faulty MAF. Should be able to find some infor on forum....
Currently driving Citroen c5 2.0 HDI 51 Plate
Galmac
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Re: C5 intermittent power loss

Post by Galmac »

I took out the MAF and gave it a real good clean with some of that MAF sensor spray. I thought it had solved the problem but this morning it was back to its old tricks. Whilst it was playing up I was trying to get more details to help with a diagnosis. I can add that the car hesitates for a second on acceleration as well. If I floor it the car hardly increases speed for a second and then it kicks in properly and pulls as it should. That give anyone any more ideas?
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Re: C5 intermittent power loss

Post by RichardW »

Hesitation on the 1.6 HDi is not uknown - and it seems to be related to the EGR valve - it's probably kicking the EGR valve as part of starting the DPF regen. My guess is if you track it you will find that it occurs at around 300 mile intervals - and if it happens on successive journeys then the first one probably ended shortly after the kick, and the DPF was not fully regenned.... As to how to fix it, well.... blank the EGR (plates available on E-bay cheaply - what I haven't got 100% to the bottom of is whether this will upset the DPF regen process); get the DPF removed (subject of discussion as to legality / MOT issues); clean the EGR valve (might only be short term); replace the EGR valve (ouch + probably comes back a bit longer than cleaning it would); sell the car 8-)
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Re: C5 intermittent power loss

Post by Stickyfinger »

Again, exactly the same early symptoms as mine (it get to total cut out), proved to be the big electrical connector (EGR) hidden under the Air Filter Box at the back or the engine.

I, (on recommendation from my Indy) cleaned the insides with contact cleaner (Maplins) and then some waterproof spray and reconnected....Never had the problem again.
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Galmac
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Re: C5 intermittent power loss

Post by Galmac »

The mechanics did check the EGR and said it was working fine - I never included this info in the original post as they said they checked something but as I don't know names for most parts of the engine I couldn't remember what they said but your posts jogged my memory! I will first try the cleaning and waterproofing the connectors as that sounds easier than cleaning/blanking the EGR valve.
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Re: C5 intermittent power loss

Post by Stickyfinger »

you need to be a "Six Fingered Octa-Monkey" to get to it from above....not tried from below....hope it works
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Re: C5 intermittent power loss

Post by momma06 »

Galmac wrote:I hope someone has had a similar experience and can help me diagnose a fault with my car (apologies if this has been asked before - I did try searching and couldn't find a similar thread). I have a 59 plate C5 1.6 HDI VTR+ Nav (diesel) and every now and then when driving the revs drop for a second. It is sporadic, sometimes it'll go a week without doing it, sometimes it will do it on consecutive trips. The best way I can explain it, is It feel like you are driving and you have taken your foot off the accelerator for a second and then reapplied it (just for clarity the revs drop not increase so I'm pretty sure its not the clutch). There is a noticeable drop in revs on the tachometer, but it lasts for about a second and then goes back to normal. It tends to happen when I am cruising/maintaining a constant speed and RPM, usually between 1500-2000RPM. I had the main dealer look for error codes when it had its most recent service and there were none, and then a month or so ago at in independent garage who specialise in French cars and they could not replicate the fault and there were no error codes. I have noticed that every time the fault occurs, when I turn the car off the engine fan is running, even though the temperature gauges are all normal and not showing any overheating (I'm not sure if this is related but it seems to happen too often to be a coincidence). If anyone has experienced this fault before and has any solutions it will be much appreciated!
Hi, just wondering if you have sorted this problem? I have the exact same issues with my c5 1.6 hdi+vtr. Any light on the subject would be a great help. Thanks in advance.
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