Idle not right

[JMS200]

Seem to have a bit of a problem with my 200. The car isn't idling properly. Car seems to idle at around 1500 rpm when I first start it in the morning and then once warmed up it seems like it can't decide whether to idle at 1000 rpm or just a bit over/under 1000 rpm. Started doing this end of last week. I also had 2 faults appear on dash "check ESP" and "check injection". I have never had a problem with the car idling before this always a bit over 1000 on startup then idles smoothly at around 750/800. My car has the centre silencer removed but that has been off for over a year with no problems to idle.
Any idea what would be the cause of this?
Could it be dirty air sensor or throttle body?

 

[Foxspeed]

is it still running smooth?

check for any loose wires and make sure all pipe that go to the manifold are on tight

need an obd2 reader to check for any faults - "check injection" may have left a fault code....

could be a faulty injector they are known to fail

also as you say - give the throttle body a clean/check just in case

 

[JMS200]

is it still running smooth?

check for any loose wires and make sure all pipe that go to the manifold are on tight

need an obd2 reader to check for any faults - "check injection" may have left a fault code....

could be a faulty injector they are known to fail

also as you say - give the throttle body a clean/check just in case

All pipe work seems to be on tight. No apparent problems there.

Car appears to be running smoothly other than the lumpy idle.

How easy is it just to remove the throttle body and what would you clean it with if required?

 

[Foxspeed]

its held by 4 bolts and one multi plug and of course the inlet hose

use something like brake cleaner/carb cleaner

 

[james_h]

Get the fault codes read - will tell you exactly what sensor is picking up the fault and give you a better idea. A lot of the codes are often misfire codes, which could be dodgy coil, spark plug, faulty injector etc - which could be the problem with your idle. Have you filled up recently? I had a batch of dodgy fuel a few years back?

As Foxspeed says, worth checking the basics as well, such as vacuum pipes on the manifold etc etc.

Here I am reading mine out on an ELM327 OBD2- similar issue, but with a misfire as well...

 

[JMS200]

Thanks for the input guys. Will have a closer look at things tomorrow morning and if needs be get it into Renault. Cars still under warranty and that's what it is there for. The check ESP and check injection messages haven't appeared again since Friday. 1 other thing was that when those messages showed up the car felt like it wanted to take off and idle hasn't been right from that point.

 

[james_h]

Thanks for the input guys. Will have a closer look at things tomorrow morning and if needs be get it into Renault. Cars still under warranty and that's what it is there for. The check ESP and check injection messages haven't appeared again since Friday. 1 other thing was that when those messages showed up the car felt like it wanted to take off and idle hasn't been right from that point.

Fault lights come on and faults are stored - especially ignition and injection faults as they can be random - after all the car is still running.

After a few 'minor' faults are stored, usually about 5 a major fault is logged and the warning lights may stay on...

All this said - if its under warranty get it to Renault!

 

[Benmc]

Take throttle body off give a good clean try again bud

 

[JMS200]

Couldn't see anything problematic myself. Car is in at Renault just now. Should hopefully know soon what is causing the issue.

 

[JMS200]

car went into renault today and they advised that nothing logged on the ECU and said they felt that there was a bit of leakage around the manifold and re sealed it and reset the ECU.

I still don't think the car is idling as it was. Seems to momentarily stop at 1000 RPM on the way back down and then settle at about 800 RPM.

If there are no faults showing up on the ECU. COuld i do some data logging and would this show up any abnormalities?

Could a dodgy thermostat cause the car to idle funny, only reason i ask is that i had noticed a couple of weeks ago the water coolant gauge fluctuating a little but has been very steady the past week or so.

 

[james_h]

car went into renault today and they advised that nothing logged on the ECU and said they felt that there was a bit of leakage around the manifold and re sealed it and reset the ECU.

I still don't think the car is idling as it was. Seems to momentarily stop at 1000 RPM on the way back down and then settle at about 800 RPM.

If there are no faults showing up on the ECU. COuld i do some data logging and would this show up any abnormalities?

Could a dodgy thermostat cause the car to idle funny, only reason i ask is that i had noticed a couple of weeks ago the water coolant gauge fluctuating a little but has been very steady the past week or so.

If the thermostat were stuck open it could effect the idle when cold I suppose, as normally would start closed and open once the engine got up to temp...if it were stuck open you could get a bit of a rough idle as the engine would take longer to warm up.

I personally think the reduction in back pressure from removing the centre section silencer could be a possibility - although you say it's been fine for a while, it could have been running too lean for a while as the reduction in back pressure could mean more air is being drawn into the combustion chamber. Saying all that I don't know if the ECU would just self adjust.

I don't know enough really about the 197/200 to make an accurate judgement but I had similar issues on the 106 Rallye when changing back pressures. I had to manually adjust the throttle body and MAP sensor.