mossman77

My OBDII scanner is reading a catalyst temperature of 446 degrees CELCIUS. This can't be right can it? I measured the inlet temperature of the front catalytic converter and got a reading of 480 degrees F and the outlet was at 380 degrees F. I then measured the under floor converter (under vehicle halfway back) and got a reading of 280 in and 180 out. This doesn't seem right to me at all. Shouldn't the outlet be about 100 degrees HOTTER than the inlet? I included some other screenshots as well in case anyone notices something suspect...

Reorge

446°C (835°F) seems realistic. Why would the outlet be hotter?
Unless your adding heat it can only get cooler.

mossman77

Because it causes a restriction and thus heat builds up inside. Every video I've watched on diagnosing a bad cat has sais otherwise, which is why I am questioning it. If it's normal, then that's very good news because replacing them is big $$$.

Marmbo

Quick search shows "The average light off temperature at which the catalytic converter begins to function ranges from 400 to 600 degrees F. The normal operating temperature can range up to 1,200 to 1,600 degrees" but I don't know what our cats run at normally.

Anicra

Should see the temp of C converter in a rotary engine

mossman77

No wonder the inside of my engine bay is hot as hell, because there are two cats under there.

Anicra

I just checked using Lemur Bluedriver ya that correct went from 600 to 880F easily

Anicra

Got it over 1000F last nite HA!

mossman77

Yeah, that was at idle. I measured 1200 F the other day when it was 90+ degrees ambient.