My '90 with Marelli displays symptoms of dying O2 (Lambda sensors). Are these bog standard sensors? The wiring diagrams show three wires: Ground (Black), Pre-heating (Brown/Grey) and Signal +ve (Green). However, the three wire sensors available off the shelf have Black for the signal and two white for the pre-heating (+ and -). Are the Jag sensors special or the same as some other brand? (Presumably the Ford influence didn't show until the facelifted 6 litre.)

I don't know if the thread is similar either, metric/UNF etc?

 

Later Jags had some unique sensors but your 1990 still uses the bog standard 3-wire sensor


Cheers
DD

 

Good (inexpensive) news

But how do I determine which of the two pre-heating wires is the ground? Or does it get additional ground through the body of the sensor? I.e. zero Ohms between body and the GND wire?

 

Per,

I am a product specialist with Walker Products, a worldwide manufacturer and distributor of O2 sensors.

You can connect either of the two white wires to the ground loop in the original sensor harness. The heater circuit has a separate ground. I hope that helps.

 

Thanks, makes it nice and simple

 

According to the wiring diagrams sensor and heater shall have common ground and sensor signal and heater ground is taken further. However, looking at the existing sensor it has two white wires llike the replacement, going into a two pole connector. Then one black wire has its own high quality screw type connector going on into a blue wire in the harness. I am wondering if the diagram is wrong and that the two white wires are the heater wires. The black one is the sensor and the sensor has its ground through the housing and thereby the exhaust -> engine -> strap -> chassis -> battery.

Anybody know for certain?

EDIT: I found another wiring diagram which shows the config I have. The blue one is O2 signal, and the two white ones are the heater. Case closed

 

ive got a set of HE single wires for sale.