|
|
|
|
|
|
BMW Garage | BMW Meets | Register | Today's Posts | Search |
|
BMW 3-Series (E90 E92) Forum
>
Pre-Cat O2 sensors
|
|
05-18-2016, 04:47 PM | #1 |
Private First Class
50
Rep 177
Posts
Drives: E90
Join Date: Aug 2011
Location: Toronto
|
Pre-Cat O2 sensors
What are peoples thoughts about changing O2 sensors preventatively at 150,000 km (100,000 miles)? Any benefits?
|
05-19-2016, 01:26 PM | #2 |
Lieutenant
139
Rep 439
Posts |
At around 100,000 miles the sensors start to get "lazy" even though they're still working.
I changed the pre cat O2 sensors on my E46 at around 90,000 miles even though I had no indication they were failing. At 205,000 miles I got a SES light (service engine soon with lean codes). I replaced the pre cat O2 sensors and the light has stayed off. So, just based on my experience with my E46, 100K has been a good benchmark and I always replace the O2 sensor on any car I own when it hits 100K miles. |
Appreciate
0
|
05-19-2016, 05:34 PM | #3 | |
Private First Class
50
Rep 177
Posts
Drives: E90
Join Date: Aug 2011
Location: Toronto
|
Quote:
|
|
Appreciate
0
|
05-21-2016, 08:35 AM | #5 |
General
18666
Rep 19,438
Posts |
On my '06 325i E90 I lost the Bank 2, Sensor 1 at 126,000 miles. The other three original sensors have remained in the car, which is now at 302,000. I've not noticed any drivability issues and I keep strict fuel mileage records. I have seen a small drop in average MPG of less than 0.5 MPG from the car's early life until now. I use the car as a DD (obviously) and my commute is almost "laboratory" consistent. I'll take the drop in MPG as due to age.
Other experience I've had with O2 sensors is my 1999 F-150 (sold it a year ago). Around 100,000 miles I lost the Bank 2 Sensor 1 on the F150. Being the sensors are not that expensive for the F150, I bought both the upstream and down stream sensors for both banks of cylinders. The sensors were Bosch (OEM) aftermarket. I installed all 4 sensors and right after the Bank 1 catalytic converter came up defective. So I reinstalled the old sensors on the Bank 1 side and the bad catalytic code cleared and remained cleared. This is the reason I've left the O2 sensors alone in the E90. My 2 cents.
__________________
A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
|
Appreciate
0
|
05-21-2016, 08:48 AM | #6 |
General
18666
Rep 19,438
Posts |
O2 sensors can really be a pain in the ass. But if you use a good amount of penetrating oil, take time, and have the right tools, they can come out pretty easily.
__________________
A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
|
Appreciate
0
|
05-22-2016, 05:21 PM | #7 |
Diamond Geezer
219
Rep 2,384
Posts
Drives: Jet Black 2007 328i Saloon
Join Date: Nov 2007
Location: Florida
|
thanks for the views here.
i've got 155k miles on my orig sensors. my mpg might be lower, but I could be driving it harder. over the last year, I started getting fuel mixture errors, and a couple misfires, even after changing all coils and plugs. resetting adaptations appears to cure the misfires and mixture errors, usually for a month or two. so, I'm interested in exploring the o2 sensor angle and hope to do some data logging on sensor voltage. any thoughts or suggestions are appreciated. |
Appreciate
0
|
05-22-2016, 06:54 PM | #8 |
Major General
1924
Rep 6,968
Posts
Drives: 2007 Black/Black 335i e90
Join Date: Apr 2011
Location: Holly, MI
|
There is a video on YouTube regarding how to change the down pipes on a 335i. Anyways about 7-8 min in, he shows you how to take out the O2 sensors on a 335i.
The pre-cat O2 sensors on a 335i will run about $225.00 for the set. It's not worth changing the post-cat O2 sensors unless they go bad. It's my understanding that all they do is check to see that the pre-cat O2 sensors are working correctly. |
Appreciate
0
|
Bookmarks |
|
|