O2 Sensor Questions

[ArnZ!]

Hey fellas,

Problems with my car was that my fuel consumption has been more then usual @ about 18l/100km around town and 12L/100on on the highway. After giving it a spirited drive or where a high load on the engine had taken place i would come to a stop and the car would idle at around 500-600rpm with puffs of black smoke coming out the tailpipe.

So this morning i did some diagnosing on the e34 535iA and my o2 sensor signal is showing a steady 0.42v...... this is meant to fluctuating between 0.2-0.7v right and if its at a steady voltage then its toast? Creating a rich or lean situation didn't change anything. It didn't even change at different rpms. On a lighter note, the heating element seems to be working good.

Now I've sourced a replaced o2 sensor, a bosch unit, for about AUD$130-140 which seems to be cheap around here and im going to install this thing myself. Now how should i go about replacing the sensor? Drop half the exhaust? Or all? and what anti-seize stuff should i use on the sensors threads?

Keep in mind that i've changed spark plugs, fuel filter, fuel pump, vacuum hoses, injectors, adjusted AFM, so ive pretty much eliminated those options.

[shogun]

go to my website below, lots of DIY>>private DIY links>>Johan & Sean, he has the info how to change it on a 735.
I still have some new Bosch 13231 oxy sensors here on stock on Japan. That are for M60 and M70 engines and maybe some more.
Oxygen Sensor; OE Version; Four Wire; Heated
The 13231 has long wires with plugs, so it might fit, provided the length of the wire loom is enough. 50 cm long with the plug/connector (round type connector. 4 wires, heated version.

535 E34 has original 13052
http://img204.imageshack.us/img204/3708/dscf0056fx8.jpg
http://cgi.ebay.com/ebaymotors/1992-...101015005r3413

89-89 BMW All Models ( 6-3430 3.4L SOHC)
91-93 BMW All Models ( 6-3430 3.4L SOHC)
88-88 BMW 535i/is ( 6-3430 3.4L SOHC)
90-90 BMW 535i/is ( 6-3430 3.4L SOHC)
88-88 BMW 635csi ( 6-3430 3.4L SOHC)
88-88 BMW 735i/iL ( 6-3430 3.4L SOHC)
90-90 BMW 735i/iL ( 6-3430 3.4L SOHC)
92-93 BMW All Models ( 6-3535 3.5L DOHC)
89-89 BMW All Models ( 6-3430 3.4L SOHC)
91-93 BMW All Models ( 6-3430 3.4L SOHC)
88-88 BMW 535i/is ( 6-3430 3.4L SOHC)
90-90 BMW 535i/is ( 6-3430 3.4L SOHC)
88-88 BMW 635csi ( 6-3430 3.4L SOHC)
88-88 BMW 735i/iL ( 6-3430 3.4L SOHC)
90-90 BMW 735i/iL ( 6-3430 3.4L SOHC)
92-93 BMW All Models ( 6-3535 3.5L DOHC)

check the length of your wires, if that fits, maybe I can offer that cheaper to you from Japan to AUS.

Even cheaper solution is a no brand one without plug, must be soldered on,
http://www.autopartswarehouse.com/mm...sor~parts.html

UNIVERSAL OXYGEN SENSOR, HEATED, 4-WIRE -- 15 cm long wiring; Includes butt type connectors and easy-to-follow instructions; Without plug; Quality tested to ensure efficient fuel combustion; A high quality oxygen sensor; Features stainless steel shell, hex nut, and shield, Teflon-covered insulated wires, high-temperature rubber internal and external seals, and threaded tube coated with anti-seize compound; Helps reduce harmful emissions;


EDIT!
the one for the M70 engine, Bosch 13231, does not fit, your 535/735 oxy sensor wire loom is much longer.
59.1in = 150 cm
see here and scroll down to Bosch
http://www.autopartswarehouse.com/mm...sor~parts.html

[ArnZ!]

thanks shogun very useful info once again, thanks for the offer but ill first try my luck here first, $140 is affordable so ill see how that goes.

With Johan & Sean DIY site, they dont have a direct write up for o2 sensor replacement but im guessing from their "gbox seal replacement" write up, that its best to drop that section of exhaust and do the sensor on a bench?

[shogun]

I am not sure on your model, on my E32 750 is just released the rear of the exhaust (added a scissor car jack under the center exhaust and pushed it up a bit to release) and center brackets, then let the exhaust drop a bit so that it just hang down. Before that I drove on 1 side on ramps, so to have more space. That gave me enough space to get the the oxy sensors on front of the cats.
Maybe on the E34 535 even not necessary to drop the exhaust a bit.
I know from the Alpina B12 E32, there it is very easy to remove the oxy sensors because the cat is much smaller than the BMW one, so enough space to unscrew it. The Alpina cats are much better, I plan to replace the OEM on my 750 with smaller ones from Germany, steel cats.

here Bruno says
http://www.bmwe34.net/E34main/Mainte.../O2_sensor.htm

[ArnZ!]

Thanks shogun, ill give your advice a go.

[BigKriss]

Thats about my fuel consumption, I replaced everything that I could think of, cap and rotor, 02 sensor, fuel injectors, spark plugs, fuel filter, ecu chip, adjusted afm, all vacum hoses and probably a few other things (liked cleaned the intake boots and) and the fuel consumption never changed.

I could never get the o2 sensor off without the exhaust removed becasue it was stuck on too tight. I guess you can lower it and have a go but thinking about it now I dont think I could access the o2 sensor with a spanner that i used. i can;t look at the car nos because I'm OS.

[bubba966]

I did an O2 on an M50TU and while I could access it from underneath the car without dropping the exhaust, I couldn't get enough force at that angle to break it free. I eventually had to drop the exhaust (dropped the whole thing in one piece). Even after I dropped it I still had a hell of a time breaking it free.

So, you might be able to get it out with the exhaust in place. Or you might have to drop some or all of it to get it out. If you're lucky you won't need to drop it at all...

[Tiger]

Easiest way is get a grip on it with any tools you can... visegrip, wrench, socket... Use hammer to persuade it to loosen up.

Those who have more room... heat up the O2 sensor with torch,,, grip it and whack it.

[myles]

I got mine off without removing anything from the car, it was just a matter or using the right tool.

[ArnZ!]

UPDATE: Finished installing the new o2 sensor, took longer then expected as i broke a downpipe stud which took ages, but in the end shes back together and already using less fuel, rich smell is gone when idling with the windows down and no more overfueling at idle.