6.0 swap with O2 sensor problem's

Hello, I have a 03 6.0 in my 95 1/2 2wd chevy truck, the engine has a Texas Speed 224R cam, their double spring's and hardened 7.4 pushrod's, with Pro Gear timing chain and Melling high pressure pump, I also have an 80 mm TB. I have a reworked original 03 harness from nelson performance that they converted to drive by cable for me, and I also had my computer tuned by them. I finally got my truck running on Thursday, and it's running good all, but I am staying in open loop, and I have 2 codes saying no signal from bank 1 sensor 1 oxygen sensor, and also no signal from bank 2 sensor 1. I have talkted to Nelson twice and they have been very friendly and helpful but I still haven't been able to fix the problem. I am using the oe 03 sensor's on the engine and they have 31k miles on them, I realize they could be bad, but I want to make sure before I go spend money on new ones. A tech at Nelson suggested that I try to ground my snesor's like the 99-02 sensor's are originally since I converted back to drive by cable, so I did that and no change. I have also ohmed out the wiring between the 02 connector's and the pcm and everything show's good and is pinned to the right positon. From what I have read the 03 and up 02 sensor's are grounded through the pcm, and the 99-02 02 sensor's have their own ground buss, but like I mentioned I have already tried grounding them like the 99-02 are. I am unsure of what to do next, but I really want to get the engine running in closed loop. Thanks for any advice!

If Ur harness was converted to dbc then the 01/02 PCM was used therefor the case grounded o2 sensors should be used. Since you have already tried that I'd say the sensors are possibly bad. Not sure what vin was used but before you buy the sensors be sure to match them with the vin. Probably gonna be an 02 truck or camaro vin. If I remember correctly both are case grounded.

Which PCM are you using?

It's a computer that Nelson supplied to me, and I returned my original 03 computer as a core, I have no idea what it is out of. I tried to see if it was a 411 etc, but the sticker was mostly missing.

If it is a RED/BLUE PCM like Allen said, then make sure you are checking the pin positions with a 02 scheme, not the 03 one. IIRC, one of the few differences in the 2 is the position of the O2 sensors wires in the plug.

Yeah it's a red blue pcm, and yeah I am using a schematic from an 02 5.3 drive by cable from Alldata.

Also I have printed out the schematic for an 03 and excuding the pink wires that are power and the low control wire on both sensor's that are the ground's, the high signal and low signal wires are pinned to the same pins in the C1 blue connector as they are in the 02. They are pin 69 high signal nank 1 sensor 1, pin 29 low signal bank 1 sensor 1, and 66 high signal bank 2 sensor 1, pin 26 low signal bank 2 sensor 1.

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Originally Posted by DRAGGIN95

Also I have printed out the schematic for an 03 and excuding the pink wires that are power and the low control wire on both sensor's that are the ground's, the high signal and low signal wires are pinned to the same pins in the C1 blue connector as they are in the 02. They are pin 69 high signal nank 1 sensor 1, pin 29 low signal bank 1 sensor 1, and 66 high signal bank 2 sensor 1, pin 26 low signal bank 2 sensor 1.

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jon is out sick today, but give him a call and have him go over the pinouts on the pcm. jon@nelsonperformance.com don't email him, cause he only checks email once a day, give a call and ask to speak with him regarding a harness we reworked, that's priority here, so you should get him on the phone, if not, leave a message and i know he'll get back.

also, send me your name so i can look up your file.

How did you ever make out ?I am having the same problem.Mine was converted to drive by wire and both my codes say both 02's not detected.

Anybody know how to wire Bosch universal oxygen sensors up to a 02 5.3 harness? Ive got them Hooked up so the pink wire and black wires from the engine harness go to the two white wires on the sensor. And then the purple wire or hi signal to the pcm is hooked to the black sensor wire (this was described by Bosch as the signal wire). Then the gray wire from the sensor is supposedly ground but the remaining wire from the engine harness is the tan wire which is the low signal wire? Is this the correct way...?