Catalytic Converter

[britgirl]

Help,

We have a 1994 camry, just put a used engine in it and while doing so found the old catalytic converter had melted. Bought a new one (ouch) and now it's overheating too, getting so hot that it glows... though the engine is not running hot, replaced the o2 sensor, checked exhaust for blockage, and replaced the fuel pump. I am at my wits end, any ideas what could be causing this problem??