Renault Megane 2.0 ide starting probs and lumpy idling

[gnl150362]

My megane takes at least 5 cranks to start, when warm has a very lumpy idling approx 750 rpm. The starting problem does not happen when engine warm. The car runs lovely when warm and there is no throttle response problems when accelerating etc.

From what i have read on various forums, something called a TDC sensor seems to be the most voted for remedy.

The car is year 2000 X, 100,000 miles and has in recent months had clutch replaced, crank sensor replaced starter motor repaired. All this work was done before i obtained the vehicle.

Any comments would be greatly appreciated.

 

[Peter.N.]

If it runs OK when warm it won't be a TDC sensor fault, the most likely problem is failure of one or more glow plugs, if only one fails the engine will start up on only three cylinders, the other one joining in when it is warm enough, this problem would normally be accompanied with whitish blue exhaust smoke, if you dont have the smoke then it will be something else.

 

[gnl150362]

If it runs OK when warm it won't be a TDC sensor fault, the most likely problem is failure of one or more glow plugs, if only one fails the engine will start up on only three cylinders, the other one joining in when it is warm enough, this problem would normally be accompanied with whitish blue exhaust smoke, if you dont have the smoke then it will be something else.

Thanks Peter for your quick response. I have probably misled you, the car is a 2.0 petrol engine which only has starting issues when cold. It has a lumpy idle when warm but no blue exhaust smoke.

 

[Burnerman]

I'd go for the coolant temperature sensor (CTS)......this wee device tells the engine ECU if its cold enough to adjust the fuelling accordingly. I trust the engine management light isn't on?
John

 

[TicklyT]

'TDC sensor' is an alternative name for the crank position sensor, which you say has already been replaced.

I did hear that Renault modified the electrical connector for their TDC sensors, and fitting a new sensor on an older wiring loom without their adaptor can reverse the sensor connections, leading to some starting and idling problems. The ECU doesn't notice the difference, as it's still seeing the sensor, so it doesn't generate any error codes.

 

[KingboyD]

Lumpy idle on the Renault IDE engine usualy means the head is blocked with excess carbon/oil deposits!

It will prob need a good de-coke!

 

[Peter.N.]

Sorry I assumed as it had a 'D' in the model it was diesel.

Peter

 

[gnl150362]

I'd go for the coolant temperature sensor (CTS)......this wee device tells the engine ECU if its cold enough to adjust the fuelling accordingly. I trust the engine management light isn't on?
John

No the engine mgt light is not on.

 

[KingboyD]

Sorry I assumed as it had a 'D' in the model it was diesel.

Peter

IDE is Renaults attempt at a direct petrol injection engine

 

[Peter.N.]

Ah right, showing my ignorance.