E36 O2 Sensor replacement

[jimiwheels]

I have just got a check engine light warning & used my code reader to get an E7 code (PreCat Oxy Sensor Switching Time, Cyl, #1-3). I assume that the oxygen sensor is bad. Any ideas on where it is... how to test them...? Thanks

:dunno

Jimiwheels (fastest white man alive :D )

[extremeM3]

Well if your car is 95- pre... there is ONE of them on your exhaust. Its right underneath your car, between your driver side front / rear wheels.. on the exhaust as I previously stated. It looks like a plug that is going into a big hole. Anyway, first go to autozone and ask for a o2 sensor tool ratchet head ( that way you can get the damn thing off). Go underneath your car, take out the sensor... clean it off with some good cleaning solution, nothing too abrasive.... then put it back in. If you still get the errors.. just change it out. Its preventative measures to change your O2 sensor(s) every 50k. If you have a 96-99 bmw.. you have about 3 of the bastards.. and that's a nightmare monetarily and physically. Procedure is the same.. you just have that many more.

[jimiwheels]

Thanks. I have a post 95 & therefore I think 4 of the dam things. The best price I found was ~ $100 bucks each.

[GPappas]

Originally posted by jimiwheels
Thanks. I have a post 95 & therefore I think 4 of the dam things. The best price I found was ~ $100 bucks each.

Even though you have four O2 sensors, you only need to change the one that is throwing the code (unless you want to change them all anyhow).

[jimiwheels]

The code that I was triggered was Pre-cat Oxy Sensor cylinder 1-3. I know that I have to replace only 1. Do you know which one is cylinder 1-3?

[KingKong]

It goes from front to back 1-2 -3-4-5-6. So, if you're standing in front of the car, the first 3 would be cylinders 1-3 respectively.

[hissinm3]

Even though you have four O2 sensors, you only need to change the one that is throwing the code (unless you want to change them all anyhow).

How can you tell which one is the busted one????

[Steve530]

if you look at the exhaust manifold, the one towrd the front of the car is for the first three cylinders (bank 1). Just follow the exhaust down toward the cat until you fin the oxygen sensor. On my 2001 530, ths is just below were the three pipes come together. It is clearly visible from the top on the right side of the car.

[bimmerZ5]

on the E36, the pre-cat oxygen sensors are further down than on M52TU and M54 engines. they cannot be accessed from the top like the newer motors.

you will find the pre-cat O2 sensors close to the coolant drain plug on the side of the block. to reach them you will have to jack up the car and get under it on the passenger side. you'll see the thing sticking out of the exhaust pipes and with a wire attached to it that goes up into the engine bay. you'll need an O2 sensor removal socket. for the E36, i prefer to use the crowsfoot offset type of socket and attach a wrench from underneath so you have to turn in reverse.

[parabellum]

It could be worse...the cheapest price for precat o2 sensors on my e46 is $140 each.

I just ordered two :(

[bimmerZ5]

the best prices i've ever found were at www.oxygensensors.com and $100/sensor is about right.

[Vanos01]

I paid ~ $65 if I remember online. And bank 1 is a PITA to replace. Bank 2 is pretty easy because it's pretty easy to reach and get the O2 tool in there. The other one is just a very tight fit. I had my mechanic do it since I had to have other work done on my car.

Best of luck.

[HGS]

do a search on the E36 forum. There has been discussion of using o2 sensors from Ford Econoline series that seem to work OK and cost under $25 each

[TrophyHusband]

I am in the middle of replacing all of my O2 sensors, and am now working on the two on the headers (near coolant drain plug. I can get to the sensors, but am unsure of where the wires connect (96 328IC).

Does anyone know how to splain where those wires connect? (picture would be great)

Andy.

[Brashland]

Why are you replacing all 4? I'm curious because I'm deliberating doing this for preventative maintenance, or just wait to see if I throw a code.

[TrophyHusband]

I had three of the things go bad and I failed emissions. So... since I have to do 3 of them anyway I'm just doing them all. $100 per. Oh Boy...
Andy

[joedinkle]

I'm having this problem also and am low on the $$ at the time. Does anyone anything about racepages.com and if theirs will fit? Mine's a 1998 323is. I'm a new member so I can't post the exact link, but a search for "1998 Bmw O2 Sensor" will bring them up. Thanks.

[Art Heritis]

Another place to try is www.oxygengeek.com (http://www.oxygengeek.com)
I ordered one for the Intrigue today & it was $52.00 delivered. Unless you really know sensors, get the "OEM" type: it comes with the connector already installed. It'll cost a few bucks more, but there's zero chance of mis-wiring them, which could happen with the "Universal" ones that you have to wire up.

[TrophyHusband]

Well, I figured out where those plugs go from the sensor. If you take the little plastic cover off of the top of your engine you will see them right on top of the fuel rail for the injectors. I have been advised strongly not to mix them up when I disconnect them.