4-Wire O2 Sensor Woes

[350yj]

Hello,

I installed a 4-wire o2 sensor in hopes of more accurate readings on cold days driving in the snow and rain. I purchased a Bosch 15733 and wired it following the included install guide.

One white wire to an ignition relay (switched 12v +)
One white wire to ground

Black wire to ECM (D7)
Gray wire to ground (I have this connected to the ALDL ground)

In Tuner Pro, the O2 sensor voltage lists at 1054.6. Once the engine is above 48*, it starts to run lean (according to my Innovate LC2) and lacks power. Also, the MIL will illuminate; Tuner Pro reports error codes 44 and 45.

Connecting a multimeter to the Black and Gray wires with the engine running shows .208 volts.

Do I have bad wiring or a bad sensor? Or am I using the wrong sensor for this engine.

Note, the old one wire O2 sensor "worked". IE, it did not cause a lean condition.

--
Kris

[Six_Shooter]

You have bad wiring from your description. You have no connection to the ECM.

[rdicarlo]

I just installed a Bosch 13077 3 wire heated 02 sensor ($15) on my long tube headers in my 87 Corvette
http://www.amazon.com/Bosch-13077-Ox.../dp/B0009IK7YW
and I used this harness adapter ($18)
http://www.ebay.com/itm/251738499118
Works great.

[350yj]

You have bad wiring from your description. You have no connection to the ECM.

I meant ECM but typed ECU.

[Six_Shooter]

When you first posted you had 3 wires going to ground, which is why I said you didn't have any wires going to your ECM by your description...

I believe you have your black and grey wires backwards, but I go by OEM wire colours on the other side of the plug, when I use a 4 wire O2 sensor, so I don't recall exactly what those wires match up to on the sensor side.

[350yj]

I will try reversing the black and gray wires tomorrow. Here is a link to the Bosch wiring diagrams I found.

https://www.boschautoparts.com/docum...sf-p3yjnLK0ksg

--
Kris

[350yj]

I just installed a Bosch 13077 3 wire heated 02 sensor ($15) on my long tube headers in my 87 Corvette
http://www.amazon.com/Bosch-13077-Ox.../dp/B0009IK7YW
and I used this harness adapter ($18)
http://www.ebay.com/itm/251738499118
Works great.

I will see if they have these sensors at my local auto parts store and give it a shot.

--
Kris

[lionelhutz]

You have the sensor ground in the wrong spot. Connect it to the tan wire on D6. I'm not positive if you still have to ground D6 (oxygen sensor ground) but it doesn't hurt to leave it grounded.

That sensor is fine for your application. The output should read <0.45V if the engine is running lean.

Every 4-wire sensor has 2 wires that are the same color. They are the heater wires. Then, between the other 2 wires the darker one is the positive of the sensor and the lighter one is the negative of the sensor. So, your wiring colors sound fine other than the sensor negative going to the wrong spot.

[350yj]

You have the sensor ground in the wrong spot. Connect it to the tan wire on D6.

I did this with no change to the voltage being read in TunerPro, still at 1054.6 volts. The engine stumbles once the ECM starts to control the fuel by the o2 sensor reading. Another interesting point, with the sensor wire completely disconnected, the voltage reading is ~400 volts.

--
Kris

[lionelhutz]

It sounds like you got a bad sensor then.

[350yj]

It sounds like you got a bad sensor then.

Thats what I thought. This is my third sensor with the same results. My multimeter shows readings which appear to be in spec. I know that its digital and may not be able to respond as fast as the o2 sensor swings back and forth.

--
Kris

[Six_Shooter]

If it's the 3rd sensor with the same result it's not the sensor, or at least not a bad sensor out of the box. Check your wiring again and make sure.

[lionelhutz]

Yes, if that's the 3rd sensor then you likely have a wiring problem or a ECM problem but wiring is by far the likely suspect since you posted the ECM did work with the 1-wire sensor.