Do I have a bad catalytic converter?

[ItchyDong]

just to be clear I have a single cat system with 1 upstream and 1 downstream O2 sensor.

I mean... ok? Nothing I've said or suggested changes, except drop the (s) off of sensor(s). I don't care if you have 12 cats, it can still be isolated with a pressure gauge and some live data readings.

 

[williambmac]

I mean... ok? Nothing I've said or suggested changes, except drop the (s) off of sensor(s). I don't care if you have 12 cats, it can still be isolated with a pressure gauge and some live data readings.

Hence the reason I told him to put a back pressure gauge on it.

 

[K_Dom]

If all you can see is upstream than your tool isn't sufficient. You'd need a tool to be able to graph the downstream o2 sensors. You can also buy or rent a back pressure gauge. You remove the upstream o2 sensor from the suspected bad bank and read the pressures at idle and with throttle snaps. No need to guess on any of this. It can all be tested and isolated.

Edit: to be clear, I'm not suggesting you have a bad cat based on your symptoms. I'm just addressing the question of whether or not your cats are bad, and giving you means and info to test them.

https://www.amazon.com/dp/B08XW1D7DC/?tag=wranglerorg-20

What do I look for on the pressure gauge?

 

[ItchyDong]

What do I look for on the pressure gauge?

You'll remove the upstream sensor, install the gauge. Check pressure at idle. Should be 0 to 1 psi. Then you'll want to do throttle snaps while watching the gauge. Anything over 2.5 psi is junk. Also, make sure you get your cats hot. Testing them cold can be misleading.

 

[K_Dom]

You'll remove the upstream sensor, install the gauge. Check pressure at idle. Should be 0 to 1 psi. Then you'll want to do throttle snaps while watching the gauge. Anything over 2.5 psi is junk. Also, make sure you get your cats hot. Testing them cold can be misleading.

Thanks. The auto parts stores near me didn’t have a back pressure gauge. I did get a fuel pressure gauge. I think that is where my problem lies. With key on it was a 14 psi and running only got to 32 psi.

 

[Gollywomper]

Thanks. The auto parts stores near me didn’t have a back pressure gauge. I did get a fuel pressure gauge. I think that is where my problem lies. With key on it was a 14 psi and running only got to 32 psi.

What is it when the rig won’t start? Drive it or let it run until then and check it. Looks like pump or pressure regulator are faulty.

 

[K_Dom]

What is it when the rig won’t start? Drive it or let it run until then and check it. Looks like pump or pressure regulator are faulty.

Not sure what it does then. Only had a loaner fuel gauge from the auto parts store this morning.

 

[ItchyDong]

FYI: running lean for a small period of time can cook a cat depending on how bad the lean condition is.

 

[K_Dom]

Replaced the fuel pump last night. Hopefully this solves some issues.

 

[K_Dom]

A quick followup to my issues. The fuel pump seems to have solved several issues. I haven't had anymore hard to start issues when my Jeep is warm. My cat monitor is now set. I also have more power in 4th and 5th gears. Thanks for all of the help. Hopefully the good trend continues.