Have Toyota Questions? Ask a Mechanic for Answers ASAP
Thank you for allowing me to help you with this concern today and am sorry to hear that this is happening. I will have to ask you a few questions so that I can get a better understanding as to what may be going on with your Corolla.
Was it pinging before the tbelt replacement?
Was the reason for replacing the timing belt in order to get it to stop pinging?
Did you perform the work yourself or used a repair shop?
What else have you tried to resolve this?
I see. The pinging is caused by pre-detonation and here is a video explaining more about whats going on inside the engine to cause this noise. I started it at 2min 12sec because that where it gets to the gist of whats important. You can watch the whole thing if needed.
The repair manual states 10 deg BTDC +/- 2 degrees. So you have some play there and is where I would start. Try 10 and if needed 12 deg to see if the pinging goes away which it should. If not, then carbon build-up or gas is where to look toward next. Does this make sense?