hey guys i bought this prelude last week and i knew it did not run extremely well.
i replaced the plugs. and now it idles fine and it drives fine but it sometimes back fires and the catalytic converter turns red and flames shoot out the exhaust.

i chekced compression and timing and they checked out ok and i have no check engine light. WHAT COULD IT BE?

please help.

 

Are you sure you are using the right timing mark? What's the fuel pressure? Is this a stock prelude with stock ecu and no VAFC garbage?

 

its bone stock nothin at all has been done

which timing mark should i be using, maybe i am doing it wrong, can you tell me how to set it right?
I have not checked the furl pressure.