vibration when the car is iddle

[mocasu]

Hi there,

I have just bought a second hand Renault Megane 1.6 16v Sport Alize, and I notice that when I am sitting at the traffic lights, it starts to vibrate...I can feel it in the gear (my whole hand will move), in my seat...when i accelerate the problem goes away, but when I stop, then the vibration comes back...Has any of you guys found the same problem?or do you have any idea of what could cause it?. Any help will be highly appreciate it!

Cheers

PS: I think this time I have posted it in the right place...hopefully!

[gavinc]

may need a service or filters

[mocasu]

It has just had a "Major" Service a month ago (also its MOT). Unfortunately (or fortunately since I hadn't had to pay for it) I am not sure what exactly was done to the car...but I will assume that at the very least they had changed oil, filters, check brakes, coolant level, brake level...(now I am struggling to think of anything else, this just show my knowledge about cars :P) ...Anyway, since it had been serviced so recently, I doubt that the filters are the root cause of the problem...

...but thanks for the advice

[AlexB]

My blind guess is that they "checked" or replaced the spark plugs and did not use the insulating grease. Now you will pay for a new coil...

[markren2004]

sounds more like a failing engine mount to me ?

[mocasu]

hi guys(or gilrs if any)...first of all thanks for your suggestions...

I went to my garage to ask to replace the spark plugs, I want them to be "bosh" , well I should said, my brother wants them to be bosh! ...Anyway, he also gave me a liquid to put in the fuel tank to clean the injectors...I have to wait for the garage to order the spark plugs and then change them...Will let you know if that solves the problem...if it doesn't then I would have to look at the engine mounts...will that be expensive?

PS: just to give a bit more info about the car which could bring some insight into the problem,it has 30000 miles, and it looks like the mileage is real (I have check them with the service history). It was run by an old lady, who could not longer drive... I wish she had noticed that before some of the scratches she has done when parking!

[markren2004]

the major service should have replaced the spark plugs (every 36k).
might be better if you give us more info about the symptoms.
is the whole car shaking...or just the gear lever ?
are the Revs idling ok and stable (just under 1 on the counter).
and is it driving normally as you'd expect.

one simple check for an engine mount is to watch the gear lever when you quickly lift off the accellerator (after accelerating hard)...if there is a lot of movement it can indicate a failed engine mount. Your garage should be able to check it.

[mocasu]

hi,

here are my comments to your response in green:

the major service should have replaced the spark plugs (every 36k).
The car had a major service a month ago but the car hasn't got 36k yet, it has 31k, thus I am unsure whether they have changed them or even checked that they were ok

might be better if you give us more info about the symptoms.
is the whole car shaking...or just the gear lever ?
i can feel it in the gear and my seat, the co-pilot can also feel it in its seat, so I guess that the answer to this is , the whole car

are the Revs idling ok and stable (just under 1 on the counter).
yes the revs are idling ok, it sit right in the middle of the 5 and 10 mark

and is it driving normally as you'd expect.
yes, while driving I cant feel anything wrong with the car, apart from a little bit of steering to the right when I let the steering wheel off

one simple check for an engine mount is to watch the gear lever when you quickly lift off the accellerator (after accelerating hard)...if there is a lot of movement it can indicate a failed engine mount. Your garage should be able to check it.
I will try that, so let me see if i got this right...i should be driving the car at "high speed", then completely release the accelerator, and see if the car moves in an expected manner?kind like balance from one side to the other?

cheers

[mocasu]

Hi all,

I have done this little test : going up to 40 Rev and releasing the accelerator, the gear knob will move initially but then it will stop and stand still, when I try to accelerate again (from a low Rev) the gear knob will initially move, and then again stand still . The movement in the gear knob, I would not call it excessive though...

Since I put this liquid to clean the injectors in the petrol tank the vibration seems to be lower,but it may be my mind playing tricks on me since I put it with the tank being full, and still over 3/4 full... could this be the source of the problem? since the previous driver was an old lady and, I am guessing here, she would drive quite slowly over a long period of time?

Cheers

[jemo]

my car has the same problem...it has only clocked 7000kms on the odometer. Went back to the dealer and they did a check on the engine and it was fine..the service advisor told me its due to the fan that is spinning if it spins faster the car vibrates even more. i was unconvinced at 1st so i did a test..when i felt the vibration, i turn the air con off the vibration stopped so its probably the fan but i do not know why the fan is vibrating so much.

[mocasu]

Hi All,

First of all thanks to all of you for your suggestions/comments.

I have just come from the garage where they replace the spark plugs. I told them if they could check the engine mounts too. They said they are ok, but they think it is one of the coils (it has one per each spark plug) is causing the problem. So I have to take the car back on Tuesday to check which one it is and have it replace!...

Cheers,

PS: AlexB...i think your blind guess was totally right!

PS: Jemo, I really doubt my car has the same problem, as it vibrates when I first start the car, thus no fan should be spinning, right? Also, I can feel it all the time regarding whether the air con is on/off.

[AlexB]

[silencer51]

Actually the 1,6 is generally 'juddery' when idling. I have driven quite a few 1,6 M2s and all of them exhibit a quite random juddering sensation felt mostly in the seat when idling. This is totally random, sometimes the engine can be completely smooth, other times juddery.

But if it becomes very noticeable then surely something is amiss - and the obvious suspect are the engine coils

[Joske]

I also have the same problem with my 05 Megane 1.4 16V. The car sort of gently shakes at idle. Car drives ok, seems a bit slow at takeoff, so i too am assuming it could be the coils, but i was wondering is there a way to test the coils?

[IainMW]

If a coil pack fails you should have a toxic fume warning message and the car will run like a dog. It will sound rough and chuffy (as it's only firing on 3 cylinders)

To me it does sound like engine mount failure (speaking from experience 3 replaced on my old 1.5dCi 100, top twice and gearbox once) It could also be an imbalance in the flywheel (1.9dCi's have had issues with failed dual mass flywheels, not sure if the 1.6VVT's have DMF?)

If the engine is idling roughly then the other things that could cause this are

1: Throttle body needs cleaning

2: Injection computer needs reprogramming

3: TDC Sensor

4: DEPHASER on it's way out

All are known problems on the 1.6VVT engine, but I would expect you would have other problems as well?