WTB Single Wire O2 sensor connector

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fly170
Posts: 4
Joined: Tue Oct 18, 2022 10:10 pm
Location: GA

WTB Single Wire O2 sensor connector

Post by fly170 »

I have searched this forum and also RealOEM and can't find the part number.
1983 E24 633CSI
looking for a part number or source for the single O2 sensor to Body wiring connector located aft passenger side of engine The part has crumbled.
Thanks in advance, Dan
TimU
Posts: 280
Joined: Tue Dec 14, 2021 2:16 am
Location: Sydney

Re: WTB Single Wire O2 sensor connector

Post by TimU »

Most (read: nearly all) O2 sensors can be divided into 2 groups.

Group 1: Wide-band sensors
5 wire = 2 sensor wires + dedicated ground wire + 2 wires for a heating element.
Generally used for modern cars.
Not compatible with E24's ECU.

Group 2: Narrow-band Sensors
All Bosch O2 sensors use the same thread type and are interchangable in the exhaust manifold's thread.
As far as my research leads, the only difference between the hundreds of different Bosch models in this group is the wire length, wire count and the joining plugs to the car's wiring harness.

Sensors in this group come in 4 different wire configurations:
1-wire = sensor wire. Sensor body is grounded via the exhaust.
2-wire = sensor wire + dedicated ground wire.
3-wire = sensor wire + 2 wires for a heating element (wires are not polarised). Sensor body is grounded via the exhaust.
4-wire = sensor wire + dedicated ground wire + 2 wires for a heating element

The 4-wire models are the most accurate with a dedicated ground wire to reduce interference, plus heating elements to bring the probe up to temp as quickly as possible.

The key take-away here is that all narrow-band Bosch models should be compatible with the E24 ECU
However you may need some modification to the wiring loom and harness if upgrading to a multi-wire sensor.

Option 1:
Get yourself the cheapest 1-wire Bosch branded O2 sensor you can find. Chop the harness off and crimp (not solder) the BMW factory harness from the old sensor to the new one.

Option 2:
As above, but get a 2-wire sensor. You'll need to run a new dedicated ground wire to the sensor's ground wire.

Option 3:
- Get yourself the cheapest 4-wire Bosch branded O2 sensor you can find.
- Replace with the the BMW harness as per Option 1.
- Run a dedicated ground wire
- Run a pair of dedicated 12V heating wires, ffused and switched by an appropriate relay.


In my '86 635csi, I replaced the $190 3-wire O2 Sensor with an $18 (yes, eighteen) 4-wire Bosch sensor designed for a Ford.
I crimped the BMW plugs to the new sensor and ran a new dedicated ground wire, following the existing wiring loom from the sensor up to the engine valve cover.
04/1986 635csi Euro spec
Australian Delivered, RHD
fly170
Posts: 4
Joined: Tue Oct 18, 2022 10:10 pm
Location: GA

Re: WTB Single Wire O2 sensor connector

Post by fly170 »

Thanks for your response TimU.
Are you aware of the single wire connector between the O2 Sensor and the wiring?
Where can I get one?
Thx, Dan
TimU
Posts: 280
Joined: Tue Dec 14, 2021 2:16 am
Location: Sydney

Re: WTB Single Wire O2 sensor connector

Post by TimU »

Just make a new harness with a new connector.
04/1986 635csi Euro spec
Australian Delivered, RHD
fly170
Posts: 4
Joined: Tue Oct 18, 2022 10:10 pm
Location: GA

Re: WTB Single Wire O2 sensor connector

Post by fly170 »

I can cobble it together as that is never a problem. However the connector on the original harness fits into a bracket with an approx 15 mm hole. That is the connector that I am looking for.
Thanks
fly170
Posts: 4
Joined: Tue Oct 18, 2022 10:10 pm
Location: GA

Re: WTB Single Wire O2 sensor connector

Post by fly170 »

Since I can't find an OEM replacement, I will use the part below which is available on Amazon. If anyone needs one, I had to buy 5.

Waterproof PG9 Cable Gland Plastic Cable Glands Joints Adjustable Connector Black for 4-8mm Dia Cable
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