Toyota Vios Strange Sound When Accelerate

[sampathpj]

Hi Experts,

I recently bought a toyota vios and there is a "kara kara" sound when accelerate. It increases when AC is on and high.

What is the problem here?

Thanks in advance.

Sampathpj

[whmsujith]

Pls check this thread, you may have the answer.

http://forum.autolanka.com/topic/13747-sound-when-ac-on/#entry220163

[Fixzit]

Probably.. what you are hearing is the Pre-Ignition knock.. which is basically the fuel and air inside the cylinders igniting before the spark plug lights up which could be due to few reasons. Most common would be ignition timing..wrong spark plugs or incorrect spark plug gap.. I'm sure your current fuel economy is not so good either... take it to a mechanic and get it checked. Maybe do a tune-up as well..as i said before there can be few other reasons as well...

[Fixzit]

Probably.. what you are hearing is the Pre-Ignition knock.. which is basically the fuel and air inside the cylinders igniting before the spark plug lights up which could be due to few reasons. Most common would be ignition timing..wrong spark plugs or incorrect spark plug gap.. I'm sure your current fuel economy is not so good either... take it to a mechanic and get it checked. Maybe do a tune-up as well..as i said before there can be few other reasons as well...

[harshansenadhir]

Assume it's got auto tranny. Then we can leave out possibilities like driving in a higher gear in slow speeds. More than pre ignition knock (self igniting), this is due to unusual burning of fuel specially due to heavy load on the engine.

This can happen in an auto tranny car due to any abnormal resistance in the drivetrain or engine itself.

Check for records of auto gear oil changes of this car. It might not downshifts properly.

Also check whether there's any brake binds of any of the wheels.

Another cause is engine runs unusually hotter and increases the resistance within itself. Check the cooling system, coolant level (once a friend complained of excessive knocking sound and engine dies. went and checked the car to see there were no coolant left in the system. Temp gauge didn't read anything unusual as there were no coolant to take the reading ), whether auxiliary fans working properly etc.

Check oil level and make sure oil has been changed properly ( since you recently bought it).

All above is assuming it's a "kata kata" noise comes out from engine. If it's continuous "chara chara " noise even in idle, better check the belts

[The Don]

Bearings and the compressor are also suspects here I think. The problem is you cannot really articulate a sound you hear with words always and a trained ear will pick it up quite quickly if they hear it.

My advice is always if you hear abnormal noises from the engine, take it to a mechanic straight away and get it checked out. It could be something simple as a noisy bearing tappets etc, but it could be the more serious as well!