engine knock Toyota corolla 141 (3ZZ-FE) Engine Knock

[baksp]

1 hour ago, Rumesh88 said:

Not necessarily so! Knock sensor is  a piezo-electric microphone which generates an electrical signal according to the engine noise. Although it is a reliable device usually if it has lost  its sensitivity it may fail to detect the knock.

Initial problem was detected in 1500 - 2000 RPM (when engine loaded).

after doing all tests in load condition, it was revealed that NO KNOCK sound occurred when thermostat and coolant temperature sensor removed (safe mode?).

fixed coolant sensor of corolla Axio and did tests: found KNOCK SOUND in 1900 - 2000 RPM.

still trying to figure out the way ahead.

 

thanks

[baksp]

Could to knock be attributed to oil seepage into cylinder as black colour residue was found in no 3 and 4 cylinders? 

[Rumesh88]

18 hours ago, baksp said:

Could to knock be attributed to oil seepage into cylinder as black colour residue was found in no 3 and 4 cylinders? 

No. You may experience intermittent pre-ignition due to heated carbon deposits but it should not cause a regular pinging noise. If you have more carbon deposits (hope it is not oily deposits) on two cylinders then there can be an uneven fuel delivery. This could result in other two getting a leaner mixture (Fuel trims common cos O2 sensor is common but delivery individual). You may have to get your injectors cleaned and checked on an Asnu rig. Make sure to mark  the injectors and swap their positions when fixing back.

Edited October 19, 2016 by Rumesh88

[baksp]

Intend inspection by removal of engine head. thanks