Useful Life of O2 Sensor?

What a great question, I was talking about this today. I've decided they have become a tune up part with newer cars. If you are going to spend the money on your DD to have the 100K tune up done, replace it. I expect they may last differently depending on type of driving, they could get carbon fouled up like valves do with easy driving. If the car is only ever driven in a way where it comes to full temp and is run hot and clean it will last longer. If you are in there it sounds like a good idea. These cars seem to be about maintaining before the problem arises. I'm sure there are other opinions, and my words get pulled out of the dark recesses of my posterior, no technical knowledge here.

 

I think in the States they must be guaranteed to last 100,000 miles however there is no certainty they will and certainly you could expect their performance to be compromised by that time if not sooner (perhaps much sooner). I installed a air-fuel ratio meter years ago in my Saab and could see very clearly when the o2 sensors response was getting slow/sluggish (time to replace at that point) and it was WELL before 100.000 miles. My plans are to install one in my 328 and two in my 355.

I think you should replace it. Get a Bosch universal type at a "sane" price and you should be good to go for some time.

Could easily pay for itself in a relatively short time just with the slight increase in MPG if your current sensor is no longer optimal.

 

O2's have not to my knowledge been part of the long term emission warranty for some time.

 

Modern cars have become more dependant on O2 sensor operation than ever before. Also they are monitored by the OBD system. In our experience testing them is a total waste of time. Their failure mode is to quit functioning or to malfunction very intermittantly and the chances are extremely slim you will be testing it when that takes place. It has also been our experience that modern O2 sensors are less reliable and have shorter lives than ever before so we replace them any time we even suspect a problem. It has become so bad we have had discussions about including them in all major services.

We replace a lot more O2 sensors on 355, 360, 550, 456 than we do on 328 if that gives you any idea of their relative quality.

 

+1 you have the full faith and support of one Fchatter, possibly others. And it got me to thinking, I'm going to change mine as well.

 

"How Long Do the Emissions Warranties Apply to Individual Parts of My
Vehicle?

For 1995 and newer model year vehicles, emission control and
emission related parts are warranted for the first 2 years or 24,000
miles of vehicle use. Specified major emission-control components are
warranted for the first 8 years or 80,000 miles of vehicle use."

http://www.epa.gov/otaq/consumer/warr95fs.txt


Not sure if an 02 sensor falls under the "major emission-control components."
I would think so but...

And, granted, this covers '95 and newer so it would not apply to a 328. This document is from March '96 but I did not see anything superseding it.

 

As of 2002 and I do not know how much earlier the Federal long term warranty only covered Cats, Motronic ECU and the operation of the OBD system only. All other components were 2 years and 24,000 miles. Californias laws are very similar but have different time periods. It is quite clearly spelled out in Ferrari literature.

 

Just replace it already, not even worth debating. A brand new, oem Bosch O2 sensor is $67 from www.rockauto.com. Shipping is less than $9. Do it, and you are good to go, and not have to worry about it failing...hell at that age it very well could be "lazy" anyway, and worth replacing. Good idea to save the old one...I save pretty much everything that comes off my Ferraris...seems all that stuff has some value...unlike other cars.

 

The OEM sensor installed in a 328 has an expected service life of 60,000 miles as per Bosch. I believe it is a 3 wire heated. If single wire, unheated, then 30,000 miles.

 

Yup, I use autohausaz and RMeuropean all the time for parts for my BMW....great prices!

 

Looks pretty normal/standard to me. In any event, only looking at the output voltage when it's in use will tell you if it's slow/bad/defective/mediocre.

 

+1. However, you are just looking at the protective cover. The thimble or sensing element is underneath. A visual inspection isn't really possible like it is with a spark plug, for example, unless there is mechanical / physical damage.

 

I wouldn't have thought the 328's would use a wide band O2 sensor? Can someone answer this?

 

AFAIK, the K-Jet with Lambda and KE-Jet with Lambda F models all use heated narrow-band O2 sensors -- are you getting different information from somewhere?

 

What is amazing to me is how they seem to work so much better in any other brand of car. How much of this increase replacement is really due to bad ferrari wiring whos contacts are sometimes partly refreshed just by the action of ripping out the old sensor and pluging in the new one? Barring wiring I again accuse Bosch of selling Ferrari their "seconds".

 

Futurman,

I would definitely replace it. If all works well, even if you remove your TWC, you should have fair emissions control. Pic below is from the Bosch K-Jetronig description manual. Figure 2 shows untreated emissions, while Figure 33 shows treated and untreated emissions along with the O2 sensor operating band. Your O2 sensor should maintain the band. Obviously, having a cat will drastically improve the emissions.

Also, these use only "narrow band" sensors...wide band didn't arrive until about 1994 and have little air pump circuits for fine linear control around lambda = 1. Also, I can't tell from the write-up or the diagrams if it is heated...looks like it could be (will need a part # and more research); anyway, since you have a lot of miles and age, it should be replaced if it's affordable ($65 = affordable)...could only improve the system. The diagram in the Owner's Manual shows three wires from the O2 sensor: one goes to the ECU; one to the relays, and; one to the frequency valve (also called the metering valve). The freqency valve is what varies the fuel system pressure for lambda control and is attached to the ECU; thus the ECU is the link between the frequency valve and the O2 sensor. The ECU controls the system (i.e., setting open and closed loop operations).


BTW, I'm still looking for the ECU diagram so as to see if the line from the CCU to the ECU/diode has any significance.
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It's not the wiring. It's also not really the O2's themselves. Bosch has the parameters set impossibly narrow in the Ferrari systems. An ex Bosch guy at one of the schools in Maranello was talking about it one time. Quite frankly many of the big suppliers Ferrari uses consider them a real pain in the butt and there is little love lost.