EFI Live V1, factory wiring harness, pcm and open loop tune?

I have been working the last several months on converting my 1969 chevelle to a 5.3 twin turbo'd, street/strip car. We are down to modifying our harness and it was recommended to come here. I posted on both Yellowbullet and LS1 and really no answers. I have a V1 I just purchased used with 1 license remaining. So I am for sure going to be using that. My 5.3 has twin PT62/62's and will run on E85. I have an LM1 that I was going to use specifically to tune the AFR. It was recommended to me to run an open loop tune. NOT a closed loop tune since I will not be driving this car cross country or anything. My harness was a drive by wire and I understand the conversion to make it cable throttle. What I am not sure of is the following. Any help is greatly appreciated because we are at a a standstill until we find out some info from this site.

1. Do I completely remove the 02 sensors and wiring from the harness and have it deleted from my factory pcm which is 4011? Or do I leave the 02 sensors wiring intake AND plugged in but somehow tune the computer to ignore it?

Here is what I wanted to do but wanted to make sure it was correct. I was going to remove all the 02 sensor wiring from the harness. I was going to plug the bungs on the downpipes once I have the tune. Drive it that way. I was then going to unplug the bung in the down pipe and hook up my LM1 when I need to check my AFR's.

Thanks for the help. Again, we are stuck on the harness until I find this out. My initial tunes will be done by a professional on a dyno jet. But I need to know what I should do with the harness first.

I just got on but I did read through some of the stickeys and tried some searches but couldn't find anything out. I am sure it is on here somewhere but we are trying to beat the cold weather coming in Wednesday. Thanks again.

Hi Sinister, welcome to the forum :cheers:

1. Edit the PCM calibration to tune the O2 sensors in/out... you will find that the O2 sensors work well for part throttle cruising.

Leaving the O2 sensor wiring in the harness allows you to have the option of deciding at any time whether you want to run the O2's or not.

If you can install an additional O2 bung (comes with the LM-1) it will make wideband measurements easier.

Thanks. Okay, the guy helping me already removed the 02 wiring. I already have an LM1 that I never got to use. I was going to hook it up on the drivers side 02 bung and plug the passenger side. This way I can monitor the AFR with the LM1 at any time. I guess I could then just have the pcm programmed to ignore the 02's. Will that be okay? I didn't know he was going to move that quick. lol I am not worried too much about part throttle cruising as long as it isn't horrible. I have been driving the last 4 years with a 13.1 compression 496 on E85. I didn't mind the idle.

Even with the O2 wiring removed, you will still need to program the PCM to ignore the O2's being gone (i.e. turn off DTC's).

[ actually it's not too hard to wire the O2's back in when needed ]

The beauty of EFI systems is that you can tune the whole driving range and have a very well mannered beast of a engine.