O2 Sensor

[BigEasyBird]

I have a 1993 325i with a burnt out O2 sensor. Do I really need to replace it? How much will it cost? How difficult would it be for me to do it myself? Any help is appreciated. Thanks

[jrhaile]

yes you need to replace it... I bought mine on ebay for about 70 bucks and it took me about 10 mins to replace. it's very simple to do too. just jackup your car a few inches, crawl under unplug the one that is plugged in, and plug in the new one...

[BLACKBMW]

Originally posted by jrhaile@Aug 23 2004, 01:06 PM
yes you need to replace it... I bought mine on ebay for about 70 bucks and it took me about 10 mins to replace. it's very simple to do too. just jackup your car a few inches, crawl under unplug the one that is plugged in, and plug in the new one...

I think that is some of the worst advice i have heard on here - and I'm an idiot!

If you are going to work under your car always use stands or a ramp...dont trust a jack - even if it's for a few minutes

I have an acquaintance who worked under his car with only a jack for support...his car was bumped while he was under it...he was very very lucky to only lose his lower left arm and not his life!

Accidents happen...play safe

J...

[nycbmw325is]

Originally posted by jrhaile@Aug 23 2004, 01:06 PM
yes you need to replace it... I bought mine on ebay for about 70 bucks and it took me about 10 mins to replace. it's very simple to do too. just jackup your car a few inches, crawl under unplug the one that is plugged in, and plug in the new one...

In addition to the safety issue, tell me dude, did you just reach up with your hand and unscrew the old sensor? Because last i checked, you need a specific O2 sensor socket with a cut out on it and at least a half inch drive rachet and some serous grunt to loosen the o2 sensor. In a word.. I think you are talking out of your ass... please defend yourself, so the other posters know what is really involved in doing something....

[gaijin1]

I have a 1993 325i with a burnt out O2 sensor. Do I really need to replace it? How much will it cost? How difficult would it be for me to do it myself?

I have the same car, '93 325i E36, M50 engine and I just replaced the O2 Sensor this past weekend.

If the "Check Engine" warning light is illuminated and you've checked the codes (turn ignition to 2nd step, depress accellerator 5 times in less than 5 seconds, count "Check Engine" pulses and it flashes code 1221) you may need to replace the O2 Sensor. It could also be a loose gas cap or in my case I had a cracked fuel sending unit that was leaking gas when the tank was full causing the "Check Engine" light to illuminate AND flashed Code 1221 (O2 Sensor). When I replaced the fuel sending unit located on top of the gas tank along with the seal, the "Check Engine" light went out.

Since I was tuning the car up anyway, I replaced the O2 Sensor as part of routine maintenance.

I bought mine online from Peilcan Parts for $101.75 (part number BW-11-78-1-735-49, a Bosch Unit).

How difficult? Replacing it is just a matter of unscrewing the electrical connector on one end and unsrewing the O2 Sensor from the exhaust system (sensor is located near the transmission on top of the exhaust system).

But be forewarned, the sensor is usually a bitch to get loose and you'll need a special "shorty" 22mm combination wrench that you can pick up at Sears for $13.99. Part Number 44130 in the Sears Tool Department.

A standard 22mm combination wrench is too long to work in the confined space where the sensor is located on my car.

You can also purchase a special 22mm "slotted" deep socket that has a portion of the side cut out so that you can slip the socket off of the sensor wire after you've used the socket to tighten the sensor. I couldn't find the socket locally so I went with the wrench from Sears.

You'll also need a tube of anti-sieze compound to use carefully on the sensor threads. This will make removal the next time easier.

You'll also need to either jack the front of the car up and place on jackstands or use drive up ramps or a lift to get under the car to access the exhaust system.

I did the entire sensor replacement in about 10-15 minutes which included getting the tools together and placing the car on drive up stands.

You can do it easily. Breaking the old sensor threads loose is the toughest part.

HTH,
Fred

[nycbmw325is]

Originally posted by gaijin1@Aug 24 2004, 02:24 PM

I have the same car, '93 325i E36, M50 engine and I just replaced the O2 Sensor this past weekend.

If the "Check Engine" warning light is illuminated and you've checked the codes (turn ignition to 2nd step, depress accellerator 5 times in less than 5 seconds, count "Check Engine" pulses and it flashes code 1221) you may need to replace the O2 Sensor. It could also be a loose gas cap or in my case I had a cracked fuel sending unit that was leaking gas when the tank was full causing the "Check Engine" light to illuminate AND flashed Code 1221 (O2 Sensor). When I replaced the fuel sending unit located on top of the gas tank along with the seal, the "Check Engine" light went out.

Since I was tuning the car up anyway, I replaced the O2 Sensor as part of routine maintenance.

I bought mine online from Peilcan Parts for $101.75 (part number BW-11-78-1-735-49, a Bosch Unit).

How difficult? Replacing it is just a matter of unscrewing the electrical connector on one end and unsrewing the O2 Sensor from the exhaust system (sensor is located near the transmission on top of the exhaust system).

But be forewarned, the sensor is usually a bitch to get loose and you'll need a special "shorty" 22mm combination wrench that you can pick up at Sears for $13.99. Part Number 44130 in the Sears Tool Department.

A standard 22mm combination wrench is too long to work in the confined space where the sensor is located on my car.

You can also purchase a special 22mm "slotted" deep socket that has a portion of the side cut out so that you can slip the socket off of the sensor wire after you've used the socket to tighten the sensor. I couldn't find the socket locally so I went with the wrench from Sears.

You'll also need a tube of anti-sieze compound to use carefully on the sensor threads. This will make removal the next time easier.

You'll also need to either jack the front of the car up and place on jackstands or use drive up ramps or a lift to get under the car to access the exhaust system.

I did the entire sensor replacement in about 10-15 minutes which included getting the tools together and placing the car on drive up stands.

You can do it easily. Breaking the old sensor threads loose is the toughest part.

HTH,
Fred

Ah now that is more like it... Post tells that you need specific tools that are not likely in everyones toolkit.... And from experience I can tell you that luck was on your side that you were able to get the old sensor out with that shorty wrench.. I have broken high quality sockets trying to get out 02 sensors...

Good post for those contemplating changing their own 02 sensors. Not as hard job just be patient and start out with the right tools.

[gaijin1]

Ah now that is more like it... Post tells that you need specific tools that are not likely in everyones toolkit.... And from experience I can tell you that luck was on your side that you were able to get the old sensor out with that shorty wrench.. I have broken high quality sockets trying to get out 02 sensors...

You're right about using a simple Deep 22mm socket for REMOVAL only. You can unscrew the sensor connector and cut the wire right at the sensor using a DEEP 22mm socket (6 point preferable).

BUT if you cut the wire, you've committed to removing the sensor. Don't panic. Just get a good wrench position so that you can lie on your back and get both hands on the 'shorty" wrench. It's tight but it'll give.

You can't get the sensor connector through the 22mm socket to use it for installation so you need the "shorty" wrench or the "slotted" 22mm socket.

There's also a wire tie "nut" screwed into the body near the O2 sensor that's used as an anchor point for the Sensor wire. 2 wire ties come with the Bosch O2 Sensor.

As for "special" tools, ask me about how proud I am of my Snap-On $53.10, S6143 Brake Bleeding Wrench? My dealer charged $69.95 to bleed the brakes and now that I have the pressure bleeder and wrench, I can do it myself in 15-30 minutes any time that I want. And man, is it SIMPLE!!!!

I also have the 32mm combination wrench needed to remove the nut that holds the fan on. I picked that up when I replaced my radiator and water pumit takes a few special tools to wrench on an E36 but you'll still be $$$$ ahead of what you'd have paid the dealer.

I bought my '93 325i new. Ask me how I know.

Fred

[jrhaile]

wow no shit about the jacking thing...I was just giving a quick summary. I always use stands incase the car falls. Also, I didn't need anything special for tools. Just a wrench (can't remember the size) and I pried the bitch off. Nothing major to it is what I was trying to express...