Catalytic converter OEM/after market?-need suggestions by Monday...

[Dwight S]

What is the CEL code? Need that to give suggestions.

 

[landarcht]

I was going to get it scanned next few days, most likely the right bank Cat like before. However, the lights went away today. I think after unintentionally shutting down the engine but still left key in on position for about two minutes while I was talking. Not sure if that did it....

 

[crimsonaudio]

I had aftermarket CATS installed about two years ago (along with all new OEM O@ sensors) - no idea what the PO had done but both OEMs were shot. Not long after started throwing P0420 and P0430 codes despite the new O2 sensors. My buddy (Toyota master tech) says the aftermarket CATS are higher flow units, meaning they're not quite as clean burning as the OEM, so the the ECU, expecting OEM CAT levels of particulates, is being triggered to display the codes. Went back and forth trying to figure out what to do, finally settled on installing a URD rear sensor simulator (Rear Sensor Simulator - Underdog Racing Development) - haven't thrown a code since.

 

[2001LC]

The dreaded CEL lights and the VSC came back yesterday!!!! It went away for about a month after I replaced the front and back O2 sensors. Now this really sucks!
What I did notice this time is that the oil pressure gauge needle stays about a quarter towards low end after I've driven about half hour. I remember it typically stays about 1/2..when cruising, what can this indicate??
Although I don't really notice any weird behavior from the car while driving. Any ideas?

One test that's been suggested is thumping CAT lightly with rubber mallet or fist. If stuff some sounds loose in it, it may be bad.

A few more things before replacing CAT:

Run a good CAT cleaner through fuel system, follow directions. Once done, drive down HWY in lower gear to get 4,500 RPM holding at that for 3 to 5 min. Then shift to drive and normal RPM to 5 to 10 min's. Repeat this a few times. This heats CATs & o2's cooking off gunk. It's like putting your oven on clean cycle.

Run a can good fuel injector cleaner through system.

Do a minor tune up. (disconnect battery for 30 min's, change oil & filter, clean MAF sensor with MAF cleaner, clean Throttle body, clean & inspect spark plugs, clean & inspect PCV valve and both PCV hose, inspect all vacuum hoses, inspect air filter, clean & grease battery connections before reconnecting).

Very very important: I've seen false bad CAT readings when engine runs cool. Weak old or stuck thermostat and engine runs cool.
After engine has cool down for eight hours, make sure coolant level is at low mark in reservoir and radiator is filled to top of neck. When engine at normal operating temp, make sure coolant level in reservoir is at high mark. Normal operating temp; instrument gauge should be at center mark and cabin heater should blow very hot. Check thermostat for proper operation, an infrared temp gun can be helpful flied test here to much up to tech stream data. Best is pull thermostat and test according to FSM procedure.

We're also seeing exhaust leaks before & after CAT give bad CAT readings, make sure there are none.

Reset CEL and pray.