C5 2.7v6 Hdi Lumpy Running

[Guest Mark Budd]

Hi,

 

My 2008 new shape C5 with the V6 diesel engine and auto box normally runs perfectly well but sometimes when cold (and possibly damp) the engine runs really erratically - much like older cars used to run if the manual choke was set to provide the wrong mixture. This is affecting the gearchange as well, although when I put it into manual the situation improves because I can allow more revs before a change. It also disappears if I drive harder but returns when driving gently. It only lasts until the engine warms up and only seems to happen in the winter months and not even every time I start. The car has done about 23k miles.

 

I would tend to suspect a dodgy connection with a sensor somewhere but where would I start to look? Has this fault occurred on other C5s and C6s with the same engine? Citroen were less than helpful suggesting that an expensive diagnostic check would only be worth doing if the problem was actually present at the time which I can't guarantee, and in any case I would have to leave the car there overnight so it was cold! By the time they confirmed the problem was there by driving it, it would have warmed up and gone away again!!

 

Hopefully someone can offer some help,

Thanks.

[paul.h]

Could be a temperature sensor problem. I would have thought it should be sorted by Citroen as part of the 3 year warranty.

[Guest Mark Budd]

Hi,

 

I'd have thought the warranty should cover it too, and it's only got a couple of months' left. Problem is diagnosing a problem which they can't see at the time. I notice too they have a disclaimer at the desk saying that I'll have to pay investigation costs if they don't find anything! Would the temperature sender be (part) responsible for adjusting fuel/air mixture then? It certainly feels like over-fuelling. It's not necessarily outside temperature related, rather I notice most when it's damp - but the engine certainly is always cold.

 

Thanks,

Mark.

[paul.h]

Usually a temperature sensor on the cylinder head will set the fuel mixture (along with the air flow meter and accelerator position) plus possibly some input from one on the air inlet to the engine. I suppose first you need to get the garage to agree/see there is a problem before doing any diagnostic checks (and then they pay for them since they think they are needed) but this would mean having the car at the garage when it is first started. It will be interesting to see what other people think and with more experience of diesels. I would also think you could go to another Citroen dealer if you are not happy with the service with this one.

[coastline taxis]

Something similar but wont affect you as yours is a auto but you never know it might point you in a direction to take . 2009 c5 2litre diesel exactley the same symptons as your but its a manual. Car was a bitch till warmed up then ran ok Turned out to be the dual mass flywheel. New one in and the car is running fine now

[Guest Mark Budd]

Interesting - I wonder if it's still the case that the warranty covers work outwith the warranty period providing the problem has at least begun to

be investigated before it expires? I'm beginning to think I had better take it to Citroen either way although they are guaranteed to hit me with a diagnostics bill whether it needs it or not!

[Guest womble]

I suppose first you need to get the garage to agree/see there is a problem before doing any diagnostic checks (and then they pay for them since they think they are needed) but this would mean having the car at the garage when it is first started. It will be interesting to see what other people think and with more experience of diesels. I would also think you could go to another Citroen dealer if you are not happy with the service with this one.

I bought my Berlingo a few months back from a Citroen owned dealership in Manchester with a 12 months Citroen Select Used Vehicle Warranty, it had to go back due to the engine fault light illuminating, trouble is we are based some 40 miles away in Stoke but no problem and they provided a courtesey car. Diagnostics came back as no fault found and the receptionist described it as a "Phantom Fault" and ok to drive.

 

The fault came back and I approached my local dealership here in Stoke. The receptionist had never heard of a 12 months Citroen Select Used Vehicle Warranty and even though I pointed out that the vehicle was showing a fault on the instrument panel SHE was quick to point out that I would be charged an hours troubleshooting in the event of No Fault Found.

 

All they want to do is take the money

[Guest Mark Budd]

I would argue they can't charge if they can't find a fault that you can physically show is there - it's not your fault if they are not competent enough to do a job they say they can!

[Guest womble]

I would argue they can't charge if they can't find a fault that you can physically show is there - it's not your fault if they are not competent enough to do a job they say they can!

I agree, that is why I want to get a hand held code reader that I know will communicate with my motor then I can get some useful evidence viz. fault codes, dates and duration to shove under their nostrils. Argue with that you so and so b**tards!!!

[coastline taxis]

Has the dealer not been upfront with you already as they told you there was no point in doing a diagnostic if the car was running ok. Some garages would take your diagnostic fee and tell you theres no faults recorded. The only way to start to sort this out is to leave it with the dealer overnight then in the morning they can plug the car in go to live data and see what the engine is doing as it warms up as thats when the fault mainly ocours

[Guest Mark Budd]

I think you are right - the only reason I have been put off is that the fault is intermittent - it didn't happen for six months during last year but returned this winter, and even then only on some days. Hopefully luck will be on my side!

 

Cheers,

Mark.

[coastline taxis]

It couldnt be when you use certain garages for fuel try and think or do you use the same garage all the time

[Guest Mark Budd]

I hadn't thought about the fuel - I normally go to a supermarket but not always the same one. A friend has a Jaguar S-Type with the same engine and his manual says you can't use as high a percentage of biodiesel as is now the norm - he has to go to a special supplier as he doesn't want to take the risk. I looked at the Citroen manual and no mention of this is (obviously) made - but it would possibly make sense with regards to my problem. It is the same engine after all so what affects the Jag should really affect my C5 too. The V6 isn't common in the C5 - perhaps I should try the C6 forum as well?

[coastline taxis]

Supermarket fuel are cheap because they bulk them up with silicone. Try a some shell ultra clean see if that help

[Guest picnmix]

Supermarket fuel are cheap because they bulk them up with silicone. Try a some shell ultra clean see if that help

Yes they add it to diesel as an anti-foaming agent but it should be in strictly controlled quantities. In 2007 someone cocked up at Harvest Energy who supply the supermarkets and added a load of silicon to unleaded petrol where it definitely shouldn't be damaging car's oxygen sensors and cost the supermarkets millions in repair costs.

 

Water in fuel is another risk a Texaco station me to me had a problem with that a few years ago and won't pay out until it became obvious as all the local garages suddenly had loads of cars with engine management faults and it hit the local papers.