Hi everyone my buddies having issues with his Blazer and so I got some tools to remove the catalytics and the O2 sensors but I also bought a computer to read what codes it was thrown and it's not powering on even when plugged into the Blazer. Should I just pull all the O2 sensors and see? I was going to take the catalytics off and put it to the replace them or clean them out but his friend already cut one off which is a problem will the engine not run as well with no cats / no exhaust? Thanks in advance I'm new to this but want to help my friend cuz he's down on his luck. On a side note a guy sold us a van after changing the odometer? Totally screwed my friend (100k miles) my ideas aren't the best hah

 

2002, EPA doesnt require cats for more than 10 years / 150000 miles last Id read their Rules.

Having no cat will slightly change things, it makes heat. No cats on my 95 4.3 and it runs clean.l and the O2 S works properly.

The sensor is two parts, a heater and a very high resistance sensor, meg- ohms level of resistance. Couldbe a shorted heater? Check the sensor wires with an ohmmeter.

Its bad to run O2S with exhaust leaks or no exhaust system, that lets air in the exhaust and could mess with the sensor readings.

If the computer is ' dark' then look for an open fuse. Pray its not a bad ground.

 

Yeah I wasn't told about them cutting out the first catalytic until yesterday so I think the first cat is clogged and or the other two sensors are messed up like you say there's four of them.

I'll check fuses. Thanks. Bought a computer just to read the thing. Appreciate it. So if I just straight piped it?

 

All it takes to ruin a sensor is temporarily running rich and putting carbon on the sensor. Or oil fouling.

Strait pipe is fine just no air leaks near the sensor. Its just a question of ground clearance with strait pipes.