Celica Forums General Discussion Engine and Performance Catalytic Converter Bad? Diagnose with OBD scanner and Excel

Hi, Mates

I think my catalytic converter is bad?
Please look at my excel data.

I read and watched on Youtube that O2 Bank 1 Sensor 1 should fluctuate between 0.00V and 0.90V
O2 Bank 1 Sensor 2 should be stable somewhere around 0.45V the entire time.

For those that don't know, Sensor 1 is before the Cat, and Sensor 2 is after the Cat.

I used Scan Tools USB device and OBDwiz software to record the data.

Cat Data.xlsx
https://www.dropbox.com/s/1cl1t1ytasj6mhq/Cat%20Data.xlsx?dl=0 (Sorry, fixed link)


BTW, my engine is leaking somewhere either from the back or from the oil pan.
Haven't been able to find out the problem yet.

Catalytic Converter OBD Data


Catalytic Converter OBD Data 2


Cat Data3

What warning codes is your obd2 reader displaying?

P0420 of course
And a pending 0446

Trouble codes

I wasn't even aware of the P0446, which is completely new to me.
I found this great resource talking about the Bypass VSV that seems to fail often on the 00-02 Celica
http://www.newcelica.org/forums/showthread.php?t=253453

I have a 2001 Toyota Celica GT-S, 168K miles

P0420 is often because of a faulty fuel cap gasket -- or if the fuel cap was not tightened to a good seal when you last put fuel in your vehicle.

1. Tighten your fuel cap.
Or
2. If when you remove your cap, you dont get a gush of pressure release, replacing the fuel cap will also clear up the code within a matter of miles.


EDIT:
Often, the P0420 will trigger another "O2 Bank x Sensor x" related warning. Fix the P0420, and the other may also disappear.

P0441 & P0455 are also related to each other.

I don't hear it often. I filled up today and will drive a lot this weekend so I will check again. Maybe the code will go away.

I have been reading that the O2 Bank 1 Sensor 2 data should be stable.
Mine is not, which leads me to believe the Cat really is bad.

I should say that I put a new fuel pump in a while back, but that wasn't the problem (Ignition coil ground was loose, causing all sorts of problems) so I put the old fuel pump back. But I busted an o-ring, so I had to get a new one. Before I got the new o-ring, my fuel pressure was miserable. I would have to turn the car over for 5+ seconds before fuel finally made it to the injectors. If I left it for more than a few hours, all pressure was lost. Once I replaced, it was much better, but I still felt that it is lacking.

I replaced the o-rings for the fuel injectors a while ago.
I also replaced those rubber gaskets on the fuel injectors that go into the engine and spray fuel a few weeks ago hoping to get some better pressure and it helped somewhat. Starting the engine could be a little better than it is now.

i feel like going to find a Celica for sale and ask the guy if I can run diagnostics on it and offer $20 while he drives just for data comparison.

Thats an interesting idea. Or check http://usedcars.automobilemag.com/toyota/celica/ for something local at a used-car lot, and get the job done with no out-of-pocket to you.