I'm getting P1138 on Gems Discovery 1. I figure I can solve this by changing the front O2's for new ones, but I wonder about the catalytic converters too.

I had the y-pipe and crossmember off to change the transmission and transfercase out. When I examined the y-pipe, I found my catalyst broken and molten. I believe that was a result of earlier problems that are no longer present, but also just the age and mileage on a car that's anything but consistent. I solved the problem for the time being by cleaning out the broken and molten material, all of it. I don't have emissions testing requirements and I'm reluctant to buy new converters because they're expensive and I've just spent plenty on a transmission and transfercase and other necessities. I'm also concerned that any number of reasons could cause misfires to come back and break the new catalysts as well.

So I'm running without them for now. I notice a rich cold-idle more than before and if there's any other side-effect, I don't know. I've read past threads on cat-deletes, o2's, closed-loop vs. open-loop, but I haven't really been able to answer my questions.

Can I get the fuel injection to work well if I just install two new O2 sensors or am I screwed until I replace the cats as well?

I have AEL and will check usual sources (AB, RN, BPUT, Amazon, etc.) for the sensors.

 

No personal experience but have read on this or another forum that these will work. I know when mine need replacing I will try them.

 

Don't replace the CATs. Nothing to gain. Only replace the pre-CAT O2 sensors, and only if you can confirm they're bad. An OBDII scanner with live data read out can diagnose this by showing the live O2 sensor values. If the voltage values don't fluctuate up and down, they're bad. You should also use an OBII scanner to read any trouble codes that may be stored.

 

Will try my Ultraguage if it's possible to get live O2 data.

I was looking at the Bosch 13923 for $90 shipped (better than AB at $129 plus stupid shipping), but those NTK's are almost half the price and based on some quick research they are correct for AEL and have the correct connectors (no splicing) and possibly even the part supplied for the Bosch-labeled item. Thanks!

 

Yes you can watch the live O2 data on the U-G.
I those NTK's are the OEM for the DI, those are what I bought several years ago.
PIA to change because of the plug location.

 

The UG showed the suspected O2 sensor was not changing voltage as expected. It would stay fairly constant while the passenger side sensor would drop voltage with throttle opening etc. I replaced both with the linked NTK's and now I get responsive voltages and a much cleaner idle, and closed loop FI.

 

Did you do anything else besides O2s? I am seeing voltage changes on Bank 2, however Bank 1 is staying constant.