So I've been having some issues with the car which led me to believe the o2 sensor was going bad. I bought a new bosch one, go to switch it in, and find the old one isn't plugged into anything. It was tucked away near the firewall with no loose wires anywhere near it. On top of that, the old and new sensor connectors are completely different so I don't know what size I'm looking for. I've looking through the FSM; didn't find any clear description.

BTW My engine was just rebuilt and tuned by Steve Kan. I have no idea why he didn't plug it in.

Which of these is the right connector and where does it plug in?

 

The larger plug for the already installed sensor is the type of connector for a wideband sensor. Do you have a gauge? The new one you purchased is a stock replacement sensor.

 

Oh that makes sense. When I bought the car there was a lm-1 wideband in the trunk. I didn't bother installing it or checking the o2 sensor at the time. Could you post a picture of the stock hook up?

 

Has your harness been modified as part of the single turbo conversion? I'm assuming it has a powerFC is that correct? The wire you are searching for comes out of the main engine harness near where it goes behind the intake manifold.

 

Yes and yes. Theres quite a few taped off wires under the UIM. I'll check which one mates up.

 

Do you have a PFC?

If you do then you do not need an O2 sensor as long as the O2 feedback has been turned off, which nearly every tuner does immediately.

 

I checked my harness and the O2 stock wire comes out of the harness right at the rear of the engine. At the same place, there is a couple ground wires coming out of the harness also.
From what I understand about the powerFC, O2 sensor feedback may be turned on or off. So the ecu might not even be responding to the sensor inputs anymore. Someone more experienced can correct me if this is wrong. May require a Datalogit to change or even check this option.
What kind of problems are you experiencing?

 

Rich conditions. Abnormally poor mpg, backfire at wot, white fuel smelling smoke out of the exhaust

 

Can be checked on the commander, go to the Etc sceen

 

I'll do that when i get back to my car tonight

 

Sounds to me like your MAP sensor hose has been knocked off. If not it is time to take it back to the persons that built/tuned it and have it fixed because something is wrong.

 

I'll check that too.

 

o2 feedback is turned off. MAP sensor hose is on tight. Pressure test is good. I'm leaning towards a bad tune. I need a new one anyway after I put on a 3 bar.