My downstream o2’s socket plug from the truck connecting the new o2 has oil dirt over it.

 

May not hurt to clean them off, and clean the contacts as well.

 

Ok I’ll update thanks again

 

Hey, I cleaned up the terminals for o2 sensor, and checked the live data in obd2 scanner, and it didn’t change from 1v. I’m not sure to check for voltage in the o2 sensor plug from the truck. It has 4 pins - the downstream has orange/black, green/white, black and black/ white wires. How do I check for the heater. I used the positive wire for the orange/black and negative on the green/black from the voltmeter. And it showed around 8 volts while the engine was running. My catalytic converter is definitely blocked, I checked for the temperatures, the inlet temperature was higher and outlet is lower. I checked again for the I/m readiness ( shows cat, o2s & htr with x mark). I’m going to replace my plenum gasket, try to clean the catalytic with ammonia and dish soap- hope it works. Any recommendations from here. ��

 

You should see 12 volts on the heater circuit..... (even going from the power feed wire to a good ground.) Sensor signal from the PCM should be around 5 volts. (also to a known good ground.) Sensor just modifies the 5 volt signal, to clue the PCM in as to what mixture ratio looks like. It *should* vary between 0 and 1 volt. Pegged at 1, it's either a bad sensor, or a short in the wiring somewhere.

Punch out the cat, or replace it. Cleaning it likely isn't going to help, as the most common failure is melt-down......

 

Which will be the ground in that 4 wires from the pcm to o2 sensor. And can I get a universal cat installed by cutting of my old cat and install with just the exhaust clamps.

 

Probably the solid black..... but, check the wiring diagram to be sure. (service manuals here, if you don't already have one.)

I think you would have a hard time installing a cat with just clamps, that didn't leak like a sieve.... I really like to weld those in.