65ChevyIINova

Has anyone had trouble getting their O2 sensors to respond after doing a conversion? If everything is wired correctly what other causes could there be that would keep the system from going into closed loop and saying both o2 sensor are non responsive (P0154 and P0134)? I have tested all the wiring and both sensors and everything works as it should. This leads me to a PCM problem...


I have a 2001 5.3L with original PCM that I put into my 65 Chevy II. When I did the conversion I deleted the B1S2 and B2S2 O2 sensors (when I had the PCM flashed, I didn't actually do this myself). I have the isolated ground o2 sensors. I Checked my wiring and the signals are going to the correct pins on the PCM (C1/blue, pins 66 69). The low reference signals are tied together and go out to c1/blue(26, 29,63) I did not tie them to the B1S1 and B2S2 low reference pins on the PCM (c1/Blue 25,28). I have also checked that both heaters are working. These are wired independently of the PCM as they were in the donor vehicle.

Cheers
Bret

lsxRanger94

http://www.lt1swap.com/pictures/isol..._schematic.gif Did you check you had a good ground for the splice pack at the back of the block.(pin 63 and engine ground)

Aaronbang

You might check to be sure the correct sensor wires are going to the correct bank ( term 69 to bank 1, drivers side, term 66 to bank 2, pass side ), if the pcm is making changes and doesn't see a response from the correct O2 sensor it could throw a code

65ChevyIINova

I have double checked all my wiring. Everything is correct but still no luck on the PCM recognizing either O2 sensor.

B1S1 is going to drivers side and is in pin 69. B2S1 is on the passenger side and going to pin 66.

Here is how I wired my setup. I put red stars on what I deleted. Originally I did not add the low reference for B1S2 and B2S2 into the low reference cluster, but since I was having problems I added those 2 wires back in but it didn't change anything.

65ChevyIINova

I am running out of ideas.

I have double checked all my wiring. Everything is correct but still no luck on the PCM recognizing either O2 sensor.

B1S1 is going to drivers side and is in pin 69. B2S1 is on the passenger side and going to pin 66. (the purple wires) I confirmed this with an ohm meter. The heater circuits are putting out 12 volts as confirmed with a volt meter. I also double checked that the pink line is positive and the black is the ground.

Here is how I wired my setup. I put red stars on what I deleted. Originally I did not add the low reference for B1S2 and B2S2 into the low reference cluster (tan wires), but since I was having problems I added those 2 wires back in but it didn't change anything.

lsxRanger94

Check your tune, they may be turned off.

65ChevyIINova

Can you turn on/off sensors with a diagnostic tool at a good auto shop or does this have to be done with a special tool? I have access to good diagnostic tools but not a 'tuner'

The tools are the fancy ones that work wirelessly to a plug in the obdii port. I will have to get a model number but I looked it up before and it is a $1,000 diagnostic system

cheers
Bret

ls1nova71

iTrader: (4)

Does sound like theyre turned off. I dont believe you can turn the O2s off with a scanner, youll need some kind of tuning software.

65ChevyIINova

Since I don't have tuning software what would be my best bet? Mail the PCM off and have it done?

Anyone here in the Dayton OH area want to help me out?

Electronics Nut

Reading your information I believe you are going in the wrong direction.

I had a similar problem which turned out to be the "WRONG O2 sensor".

GM has two different sensors for this application an isolated ground and a case ground sensor, it sounds to me like you are using an isolated ground sensor with a computer that is designed for a case ground sensor.

To confirm this add a ground (do not disconnect any of the existing wiring) to the tan wire from the O2 sensor. If the computer now sees your O2 sensor you can either replace the O2 sensors or add a ground to each sensor.

I hope this helped, good luck.

130fe

iTrader: (14)

Yeah, I helped a local friend on his LS swap in his 70 camaro and he had a similar issue. The O2 sensor harness (411 PCM) had the same plugs as his 04 silverado. Not knowing they were different, He put them in and when we were trying to tune it, the O2 sensors wouldn't read on the HP tuners program. As Electronic nuts suggests, the 98-02 F-body and 04 silverado O2 sensors had the exact same plug but were wired differently. My friend put in a set of the F-body ones in and it worked perfect. What type of plug does your harness have? I know there are a couple of different ones for LS series harness.

lsxRanger94

Isolated ground o2 sensors with work with a case grounded pcm(411) provided they are wired like below schematic. Tan wire is ground reference. provided there are no breaks in the wire, it will work. Isolated ground sensor will typically have a white square plug on the sensor and case grounded will be a flat 4.

http://www.lt1swap.com/cable_conversion.htm

65ChevyIINova

My engine/pcm came with the square plugs. It also had Bosch 13193 o2 sensors that I replaced with new ones. The harness was wired like the isolated ground setup so that is what I rewired it as. I have checked the wiring so many times that I dont believe there is a wiring problem.

I tried to add the chasis ground to the tan wire bundle and it didnt seem to change anything. My scan tool just kept flashing the o2 symbol indicating that it cannot connect to the o2 sensor.

lsxRanger94

Since you are not seeing the o2s and all wiring is correct with new o2s, I'd have the original person check to see if b1s1 and b2s1 are enabled in the tune. Sometimes mistakes are made since no one is perfect. Especially if it's late and your wife's calling bitching about when you are coming home because dinner is getting cold. LOL

Shando817

So did u ever get to the bottom of the issue.

G Atsma

After 4 years, you expect an answer?