An interesting article here from another site. This guy seems to point the finger at timing. It's something that's crossed my mind too, since I've just done the timing belt. However, in my defence, the cam timing tool slotted into its groves at the end of the camshafts, albeit with a little encouragement, with the crank pegged. Has anyone on here experienced these symptoms after having done the timing belt AND been able to rectify it by reviewing/resetting the timing ? If needs be I'll rip the thing apart again and attempt to set the timing from scratch, but I'm scratching my head as to what I would do differently from before ?
"One of the most common reasons for a clio 172/182 to idle poorly is the cam timing is slightly out.
It is a speed vs density fueling algorithm on these cars not a mass air flow based one like on most modern cars so is a relatively unusual problem and fairly unique to have that in combination with also having fully floating cam pulleys on the same engine like on these cars so most mechanics wont have a clue about it.
So if you have something that makes a significant change to volumetric efficiency at idle like incorrect cam timing it means that the engine displaces a different amount of fuel per rotation of the engine than the data in the ECU has been programmed to expect.
As a consequence it delivers an incorrect fuel mixture and makes the car run lumpy.
When the car warms up the ECU then starts to reference the lambda sensor and switches over from the open loop fueling tables to the closed loop strategy and corrects itself in real time to compensate for the differences between VE and what it is programmed for on its open loop tables.
But people STILL insist on using shitty backstreet garages who dont understand the very specific requirements of these engines cause its a few quid cheaper than a specialist and then they wonder why they get problems!
Wear and tear can have a similar effect or can exaggerate the effect if its combined with slightly off cam timing.
If the problem is just down to wear and tear where the Ve drops as the rings get worn and dont seal as well and valve seal being imperfect compounds the problem then a remap (please not by some cheap and cheerful “chip tuner” with a slave unit who will make it worse as they wont understand the effect of adaptions on long term fuel trims etc, go to a proper renaultsprot specialist mapper) can often provide a suitable workaround for the problem, if all else fails then a slight increase in idle speed (like the RS Tuner remap introduces) is another way to solve it."
Having done a bit of [soul] searching this morning, I also found this note on another site. They seem to be highlighting issues with the dephaser solenoid. It's also timing related.
"The solenoid valve is closed at rest. It authorises the passage of oil to control the phase shifter in line with the operation of the engine: - if the engine speed is between 1,800 and 6,500 rpm, - if the throttle potentiometer is not at no-load NOTE: if the solenoid valve is jammed in the open position this will result in an unstable idle and the pressure in the manifold at idle will be too high. This affects the mechanical timing of your inlet valves and the other mechanical components: pistons/exhaust valves. The result will affect the volumetric efficiency of the engine, hence a change to the fuel and ignition maps. The solenoid only opens or closes as detailed above and it is not continuously variable."
