Page 1 of 1
LS Swap LQ4 02 sensor wiring
Posted: Fri Feb 10, 2023 11:20 am
by Grand_Wag_85
Trying to make sense of the 02 sensors for my build. Engine is an LQ4. The swap harness that I have does not connect to my 02 sensors as the plugs are different. I need to figure out the wiring so I can butt them up.
The sensors are:
BLACK
BLACK
BLUE
WHITE
The wiring on the truck:
RHS:
TAN
PURPLE
GREEN
PINK
LHS:
TAN
PURPLE
BLACK
PINK
Re: LS Swap LQ4 02 sensor wiring
Posted: Fri Feb 10, 2023 11:41 am
by Yeller
O2 sensors are a pain….. never understood why they have so many different connectors for a 4 wire sensor.
I know they are expensive…. I would buy the correct O2 for the harness. But to be clear are you looking to change the plug to the plug for your sensors are are you looking to eliminate the connector all together? With O2’s being a disposable part I would want a connector.
I own one swap that the O2’s do not read, the ecm sees them but they just flat line and could not figure out why. Was having that engine dyno tuned anyway for other issues that were known prior to the swap. they cleaned up the fuel maps and it runs great from sea level to 14,000 feet.
Re: LS Swap LQ4 02 sensor wiring
Posted: Fri Feb 10, 2023 12:12 pm
by Grand_Wag_85
Yeller wrote: ↑Fri Feb 10, 2023 11:41 am
O2 sensors are a pain….. never understood why they have so many different connectors for a 4 wire sensor.
I know they are expensive…. I would buy the correct O2 for the harness. But to be clear are you looking to change the plug to the plug for your sensors are are you looking to eliminate the connector all together? With O2’s being a disposable part I would want a connector.
I own one swap that the O2’s do not read, the ecm sees them but they just flat line and could not figure out why. Was having that engine dyno tuned anyway for other issues that were known prior to the swap. they cleaned up the fuel maps and it runs great from sea level to 14,000 feet.
I bought an adapter that ended up being incorrect so I'll take the one pigtail off and hardwire it in. That way the sensors can still be changed. It kills me because the sensors were expensive and are correct for the donor vehicle.
Re: LS Swap LQ4 02 sensor wiring
Posted: Fri Feb 10, 2023 1:29 pm
by Yeller
That's frustrating for sure..... Wish I had the diagram for you with the color codes. The only thing I know to do is find out what pins are what and trace them with an ohm meter.
about fired my harness guy over my truck.... been using him for 15 years without issue, he forgot the OBDII port, cruise control wiring and put a DBW program in for my DBC motor, chased that for 2 months. Wouldn't have taken so long if he wasn't 3 hours away.
Re: LS Swap LQ4 02 sensor wiring
Posted: Sat Feb 11, 2023 11:16 am
by tgreese
Yeah, I would trace the wires back with my multimeter. Find the connections at the computer for the heaters and sensors and follow them out to the sensors. Or start at the sensor and trace back to identify that connection.
Re: LS Swap LQ4 02 sensor wiring
Posted: Sat Feb 11, 2023 11:45 am
by tgreese
This only took a minute or two of searching -
heatedsensor (662 x 204).jpg
in this thread
https://www.thirdgen.org/forums/diy-pro ... lysis.html
Looks like the heater is not under computer control.
I would not take this as the answer to your question, but instead to send me in the right direction.