Focus Engine Ping/rattle Help Required!

[RyanB92]

Hi all I'm looking for a bit of advice regarding a problem with my 2009 Focus 1.6 petrol.

I have noticed for a while that there is a metallic rattle that comes from the engine bay when accelerating at low revs, for example pulling away from rolling in 2nd gear then pushing the accelerator to get up to speed I hear the rattle for a second then it's fine. I don't get the noise if I give it enough revs.

I can force the car to make the sound if I travel at approx 30 mph and put the car into 5th gear then floor the accelerator the rattle will occur for a short time like a second then the car will gradually build up speed whilst labouring.

I initially thought it was exhaust or heat shield rattling around. But my dad seems to think it's engine ping/detention etc.. I have checked under the car for heat shield rattle and can't find anything untoward.

I have a ford f super 2 diagnostic lead and soft wear coming Friday and will try this to see if any of the many sensors are playing up. Has anyone ever had these symptoms on a car?

Also whilst carrying out an oil change yesterday I was looking around the engine bay whilst the engine was running and see that the bottom pulley on the crank (runs the AC compressor) was wobbling around like it was out of balance or the rim of the pulley was bent on one side. The outer pulley directly next to the air con pulley runs fine and true? I found out that this pulley is a vibration dampener? Is it supposed to move around like that?

I would appreciate any feedback from any ones knowledge and experience. Sorry for the long post but want to put as much detail down as possible.

Thanks

Ryan.

[ForTim]

Did you solve it? Was it like this link or it was compressor pulley?

 

[simcor]

Could be the bottom pulley tensioner, mine was really bad and made a horrible metallic rattle sound on acceleration.