Megane accelerated on its own!!!

[Bazoh]

I've had my megane 1.9dci for a few years now and had endless 'injection fault' lights appearing, (usually a glow plug problem) so when it happened this time, and non of the cars performance was affected, I figured it could wait a few weeks until I had some extra cash to sort it.

Yesterday morning I was on my way to work when I noticed it was losing power at low revs, it was only slightly noticeable so thought this would be a perfect time to book it into the garage.
On the way home though, not only was it losing power at low revs but it suddenly stopped being able to accelerate above about 2500 revs (I figured this was a 'get home safe mode' that I'd encountered before). To test what was happening I dropped it down a gear and tried to accelerate.This time the revs went up and the car started to accelerate, for a second I thought it was fine, until I took my foot off the accelerator and the car continued to increase in speed. I then engaged the clutch to slow it down and the car started to rev uncontrollably. Worried that the car/engine would get damaged at such high revs I engaged the clutch again and the revs came back down. Luckily I spotted that there was a lay-by coming up, using my brakes and by gearing down I started to slow the car. I got the car down to second gear and the revs finally died down allowing me to stop and put it in neutral. With the engine still running I blipped the throttle a few times and noticed that if the revs went above about 2000rpm the engine revved of it's own accord but eventually slowed back down. Thinking I could limp the car to the nearest Renault garage I foolishly tried to continue at really low revs. After going about 2 miles I started to enter a town and again the car started to accelerate without me pressing the peddle, again I engaged the clutch, and again it screamed uncontrollably. I engaged the clutch again and the car continued to increase in speed, I tried pressing the stop button a few times but this did nothing, luckily I managed to slow the car down in a low gear and finally stall the engine.

As you can Imagine this was all quite distressing, luckily I'm reasonably mechanically minded and knew how to bring the car to a stop and how to stall the engine. If this was to happen to someone who wasn't as experienced with cars or driving I wonder what the outcome might be. God forbid if it was my wife driving an uncontrollable car.

The car is currently at a main dealer and I'm awaiting a diagnosis, until I do hear something I just wanted to give everyone a warning about this and also ask if this has happened to anyone else.
Let me know your thoughts.

[AlexB]

Was there any smoke? Check if any oil was lost. Any whistling from the turbo?

Hi and welcome, of course!

[Bazoh]

Yes there was smoke, lots of smoke!!

[AlexB]

This was described many times -- the turbocharger is gone, it started gushing oil into the induction system and the engine was running on its own oil as fuel. Apart from the turbocharger the engine itself can be damaged by running dry, overrevving or as a result of running on dirty oil, which might have caused this failure in the first place. Could you please describe the history of the car?

Read Parkers forum for more stories like yours and about the Yellow OTS scheme of Renault, under which they replace failed turbos or engines for free. They have, however, very strict eligibility requirements described in the same forum. Once you are at Parkers read TOPIC 1 first! Antmat is the expert on this subject.