O2 Sensor Issues

[itsdesignateddave]

First off I'd like to say thanks for everyone here. I've been reading for a month or so and have yet to post. I purchased an 05 XRunner with under 40k miles that had a TRD supercharger, DTLT headers, and magnaflow exhaust already installed.

My dad has been with Toyota for over 31 years, and one of my best friends is a certified Mazda mechanic and both have different ideas as to what is causing the issue. Right now there is some type of a bypass system for the O2 sensors, they are plugged into some type of aftermarket wiring harness. (I would like to give you more info about the electrical, but it's been 100 plus degrees for almost 2 weeks and I haven't had a chance to get under it but once).

Anyhow, the passenger side has the O2 sensor installed, and the drivers side looks to have a block off (large allen head flush mounted insert) in it's place. I am getting codes on each of them. A P0137 and P0157 which refer to "O2 sensor circuit low volts." Bank 1 and Bank 2 sensor 2 on both.

I'm not big on aftermarket wiring, but my friend says that it's running rich, will eventually foul the plugs, and obviously waste gas. He says as long as bigger injectors were installed it should be okay to install the other O2 sensor and hook both back up to the factory harness. Has anyone had an issue similar to this?

My dad thinks because it's aftermarket it could still be lots of different issues, but we haven't gotten together to work on it yet. Any help to point us in the right direction to start would be helpfull.

Thanks,
David

 

[shaggy08xr]

When you have dtlt's you will have to use an o2 simulator from URD because the long tubes delete the front two cats. You sound like you already have that, but it also sounds like some one took out one of the o2 sensors and used that port for a wideband gauge to monitor afr's.

Without seeing anything I hope that helps a little.

 

[itsdesignateddave]

At this point I understand what you're saying, but have no idea what i'm looking for. I will have to get a few pictures up once I can post them and see if that helps. I finally got the change to crawl under it yesterday for the first time, and I wasn't really sure what I was looking for as far as aftermarket, so I will see what I can find out.

Along those same lines, what aftermarket part (wiring harness?) would plug into the port where you plug the diagnostics reader into under the dash? I don't think I've had a vehicle where I actually had to unplug something to read the code before.

 

[shaggy08xr]

Your best bet is to go with an ultra gauge. It plugs right into the obdII port and has a bracket to mount the display right to the windshield. This gauge monitors 53 different sensors on our trucks, gives trouble codes and allows you to clear troubles

Here is the website and there only 59 bucks right now:


http://www.ultra-gauge.com