V8 O2 sensors - which way around?

[Ferret]

Guys, which way around do the plugs go on a 540i... I distinctly remember a shogun post a while ago saying that on a 7 series V8 the left sensor plugs to the right socket and visa-versa - is this true for an E34?

Was under the car the other day and noticed the left sensor in the left socket and right sensor in the right socket - the car ticks over well, but I'm only getting 17mpg out of a manual 540... when I should be able to easily push it over the 20 mark!

I used to get 22 ish - I think one of them may have gone duff! Will get under the car at some point and check them out.

[Ferret]

Cheers gents, I think I'll be brandishing a multimeter at the car one evening this week :D

[shogun]

No, that was a wrong installation by someone in Germany who put it on his website. Sorry for that.
You can measure the 02 sensors at the MOTRONIC, here the info for an M60B40 in a E32 740 01/1994 production
right cylinder bank (1-4) on Pin 13 and ground on Pin 40
left cylinder bank (5-8) on Pin 12 and ground on Pin 39

You can measure, the cable from pin 13 goes to 02 sensor cylinder 1-4 (right side) and pin 12 on cylinder 5-8, = left side!
You only have to measure on the DME pin connector and pin 2 of the 02 sensor! The 02 sensor pins are marked.

[winfred]

sensor 1 is the right (cyl 1-4) and 2 is the left (5-8) when reading codes/data, i can't remember on a e34 if the wires are a different length like they are on the e38/39 the harness wires are fairly obvious which is which

[shogun]

sensor 1 is the right (cyl 1-4) and 2 is the left (5-8) when reading codes/data, i can't remember on a e34 if the wires are a different length like they are on the e38/39 the harness wires are fairly obvious which is which

yup, thanks winfred.
To check the sensors on the MOTRONIK, teke off the connector, remove the cover from the connector, the install the connector again, let engine run, and then you can test easily the 02sensors on top of the MOTRONIK connector, each pins number is shown there.
No need to crawl under the car. You could even drive the car with that, so testing the 02 sensor in action, just use extended wires from there to the multimeter which you put inside the car on the dash or console for reading the volts.