Hi,my first post. I've got an fiat idea 1.4 16v 2004 and I've just done timing belt and since doing it I noticed a tinny sounding rattle like some thing is loose and vibrating at 2000 rpm till 3000rpm below 2k it's so quiet and smooth tick over,above 3 k it sounds sweet an very responsive but between 2k & 3k rpm sounds like a tin can rattle from inside car while driving but today I set rpm at 2.5k and put my head under bonnet and it sounds like top end of engine rattling around cylinder no4 ? Any ideas ? PS before belt change I didn't notice the rattle sound

Hi there,

No one has replied yet I see, maybe you even have solved it perhaps?

However, I do not know the engine well at all so please forgive me if I'm wrong.

From description of the noise and with it only being between certain rpm I would suggest (if engine has it) the VVT system may be worn. (Variable Valve Timing).

Thanks for your reply, I found the problem it was old school term = pinking, timing issue due to faulty timing belt tensioner? Replacement of tensioner and refit of belt it's now quiet and no top end rattle

How is the idea?

The one I had was good.. but the duologic was going to be bad news in time..

Charlie

BritSons said:

Thanks for your reply, I found the problem it was old school term = pinking, timing issue due to faulty timing belt tensioner? Replacement of tensioner and refit of belt it's now quiet and no top end rattle

Click to expand...

Pinking is the term used for "pre-ignition" due to the engine spark timing being too far advanced and/or the spark plug running to hot. When these happen the the fuel mixture does not burn with a progressive flame front and gas expansion but instead "explodes" creating very strong shock waves that result in audible "knocking".

At low engine RPMs the knock sound very much like a diesel engine clatter but with a little extra "ring" to it. If allowed to consistently occur over extended periods of time engine damage can be done.

At high engine RPMs then pre-ignition can be inaudible. If you can hear it then it will sound rather like a collection of small washer rattling around. High RPM pre-inition is the most dangerous and can lead to rapid engine failure, holed and melted pistons.

With your tensioner then it was a mechanical failure/fault and not associated with actual engine timing. Possibly a too weak or broken spring.

Also an incorrectly adjusted dynamic spring loaded tension that "floats" as opposed to being locked down then knocking is a classic case of and incorrectly set tensioners. In these cases then the tensioners will "top out" or "bottom out". Often when this happens it only occurs during the cold engine start and warm up phase as the engine is running rich/lumpy.