Adjusting Idle Speed

[Tuscan1969]

Hi All,

 

My 2004 C5 2.0 SX petrol is garaged over night but still hates the cold weather. It allways starts fine but within 30 seconds the idle slows right down and the car runs rough - it will frequently stall and trigger the catalyst and anti pollution failure lights (although I know there is in fact nothing wrong with these as the warnings go off later the same day once the car has been driven around enough and is properly warm.)

 

.....so whats the problem guys? Is there some faulty sensor somewhere (the garage can't find one but they are not a citroen sepcialist so their diagnostics may not log all faults?)

 

Any ideas gratefully recieved.....

 

PS it had a full service inc filters and plugs etc only 1000 miles ago and its only covered 54K...

[paul.h]

First give the inside of the throttle body and plate a clean with carb cleaner or turps on a cloth to remove any carbon build up - this should be done each service on any car. Also have a look for any hose splits. If then you still have problems it could be the coolant temperature sensor that is faulty.

[coastline taxis]

do you have any fault codes. And good advice of paul as the temperature sensor acts as choke on the petrol engines

[mlkey]

I also have a 2004 SX petrol, and while I do not have the stalling during warm up, it does start to run rough after about 30 seconds to 1 minute. Once it has warmed through it drives like a dream.

 

I have Lexia and there are no fault codes. I have also done a lot of research about this, the only thing I have come up with is that there was an issue with the hydraulic cam followes. There are various accounts on the internet, including several Citroen technicians saying they have change them and cured the car. I work with 3 Citroen technicians, none have heard of this. That said, it is affected very quickly when you start the car, indicating whatever it is is subjected to a fast temperature change, valve lifters would fall into this. I have also checked all sensors and they are giving good readings.

 

I plan to try another set of followers next year as that is the only thing that spoils the drive on an otherwise faultless drive.

 

Hope that helps.

[mechcanico lee]

Hello Mikey i have seen this fault a few times on peugeots 206cc and 307s with the 2.0l 16 valve engine (think the eng code nfx but not sure )is this the same engine as the c5 petrols ??

Like the other post says they have modified hydraulic buckets , basically as the mileage of the engine gets higher laquer builds up in the hydraulics and they carnt releive the oil fast enough from cold when the oil is thick and less viscous , this results in the valves being jacked open and it makes the car run really rough and sometimes stall (the fault may not be there through summer months )

 

You can go down the route of changing the hydraulics for the modified ones , quite expensive and fair strip down or ......... use a flush in the oil first , take for a run to get it flushed around properly, drain oil ,change filter and use a 0w 30 grade oil , in the ones i have done this as worked quite well with only reports of slight roughness on the coldest days ....like under -3 degrees and the likes, the 0w grade just helps with the cold start period .

 

Not saying this is your fault but your symptoms sound familiar to this , you say it was serviced recently ...do you know what grade of oil was used?

It could be what Paul says throttle body clean and re learn new adaptations ,either way all these things want cost much money to have a go at .

 

Lee

[mlkey]

Hi Lee,

 

I was not the original poster, just saying I have the same issue. My car has 42k miles on it now, I got it with 31k. I have done flushes and use either 5w 30 or 0w 40 oil. I suspect it is cam followers / buckets in my case and will be changing them soon.

[mechcanico lee]

Sorry Mikey

Looks like you have been down that way then with flushes and oil grades and so on , it a bit of a pisser though that you have to take it all apart to fit the modified buckets coz its still a low mileage car as mileage goes nowadays , if you think about it worked ok when it was new , so its just as the mileage gets higher that this fault occurs.

 

We have another additive at work for hydraulic followers , its for when they get noisy like the clack, clack sound you get from them , this gets rid of laquer build up also , this is more a treatment which goes in the oil ....it can take up to 300 miles to work fully ,its made by Wynns .

 

Just trying to try all other methods before you have to open it up and spend the dosh on the buckets and other related parts to see the job out.

[qman3428]

Had this fault on a similar aged C3 it turned out to be the Mass Air Sensor, no fault codes showed but when the MAS was changed it then showed the EGR at fault so it looked like the two faults counter balanced each other. MAS was £80 and the EGR was about £40 both from the main dealer.

[Tuscan1969]

Hi Again Everyone,

 

Thanks for the advice / thoughts....just to add some more info.

 

- the water temp sensor was replaced but has made no difference (NB the oil temp is ALLWAYS low and seems to take a long time to get towards the middle reading....is this sensor worth changing?)

- no fault codes are logged and

- I have tried hydraulic lifter additive to no avail.

 

As my car is the petrol model I dont think there is a EGR to change (isn't that only on turbo cars?)

 

 

Any other thoughts.......

 

Many thanks for your help...

[mlkey]

Hi Again Everyone,

 

Thanks for the advice / thoughts....just to add some more info.

 

- the water temp sensor was replaced but has made no difference (NB the oil temp is ALLWAYS low and seems to take a long time to get towards the middle reading....is this sensor worth changing?)

- no fault codes are logged and

- I have tried hydraulic lifter additive to no avail.

 

As my car is the petrol model I dont think there is a EGR to change (isn't that only on turbo cars?)

 

 

Any other thoughts.......

 

Many thanks for your help...

 

I still think it is the followers... as I do with my own car. I have tried the additive too, also oil flushes and running a 0w40 oil. There are various websites suggesting this is the issue, so I will be saving my pennies to give it a go next year.

[mechcanico lee]

You can diagnose it if its hydraulic buckets ................

 

you need a engine vaccum guage , find a take off point on the inlet manifold (theres normally somewhere u Tpeice into)

 

When you start up good vaccum on a good engine will be bout 20/21 inches of mercury ,if you let it run keep watching the guage when it starts to run rough the vaccum will drop and you get a pulsing effect on the guage, the pulsing is the compression being let into the inlet manifold because the valves are being held open by the buckets jacking out .

[paul.h]

Do not bother with the oil temperature, from memory it is combined with the oil level sensor, and it is normal for it to go up slowly - it does on our car and I have seen it mentioned before here. I do not know why there is a gauge for it and it probably does not go into the engine management.

 

Draper do a combined pressure/vacuum gauge for about £11. Search on Draper petrol engine vacuum and fuel pump tester.

 

The petrol engines do have an EGR valve (Haynes manual page 4A.15).

[mlkey]

I have been checking things on the Lexia, the air intake temperature sensor was reading high compared to coolant and ambient temperatures on a cold engine by some 6c. As the sensor was cheap I changed it. The new sensor is giving the same reading, so that is now ruled out.

 

I will do an oil flush and change tomorrow, maybe add some Wynns Hydraulic Lifter treatment too as we are going on a 300 mile round trip on Saturday. I will report back with any results.

[mlkey]

Another oil flush done, added a bottle of Wynns hydraulic lifter treatment with the new oil. Tomorrow is a 300 mile run weather permitting, will see how it goes and report back.

[mlkey]

Another oil flush done, added a bottle of Wynns hydraulic lifter treatment with the new oil. Tomorrow is a 300 mile run weather permitting, will see how it goes and report back.

[mlkey]

Another oil flush done, added a bottle of Wynns hydraulic lifter treatment with the new oil. Tomorrow is a 300 mile run weather permitting, will see how it goes and report back.