Before anyone asks. Yes the engine was actually that clean on the inside. I know. I couldn't believe it either when i first saw it. Im the Second owner and the car has been very well maintained. Oil changes especially. Always had Mobil one in it.💯

 

Ok did it fire up after doing it?.... if so I bow to your tenacity and DIY-ness, i might have tackled the job...but mine is ^%#$%^&*b transverse

trip

 

Yes it fired up no problem. It developed a misfire the next day. But that was just a coil pack going bad. I replaced it and everything is fine. I actually did the job over the 4th of July week and the car is running great. I had a hard steer problem at idle before i did the job. So i went ahead and replaced the power steering pump while i had it apart. Now it works great.

 

Bet it runs way better with the new timing set. Does it have new spark plugs and O2 sensors as well?

 

It actually ran great before i changed everything. The check engine light was on and showing a cam/ crank coalition code. That's why i decided to change everything. It definitely seems to have more power since i changed the timing components though. The oil pressure and steering at idle has also improved since i changed both pumps. I did install new plugs but didn't change the o2 sensors. The o2 sensors haven't gave me any problems so far. Im planning on changing to the cross drilled rotors at the end of August along with installing a new steering wheel. The leather is starting to degrade on the factory installed Brown one.

 

The o2 sensors haven't gave me any problems so far.

That's like saying "my spark plugs haven't given me any problems so far" because the engine still starts and runs. O2 sensors are wear items, although not quite as fast as plugs. Every time I've replaced 100K mile O2 sensors the car has run better and fuel economy has picked up 1MPG or more. No, the check engine light won't tell you this.

 

The o2 sensors are a work or don't work item. There is no in between. They read fuel air mixture in the exhaust gasses and send a signal to the ECM so it can keep the mixture at 14 to 1 ratio. I have been s ASE certified mechanic for almost 45 years. Theirs no set mileage for replacement.

 

LOL

 

The o2 sensors are a work or don't work item. There is no in between. They read fuel air mixture in the exhaust gasses and send a signal to the ECM so it can keep the mixture at 14 to 1 ratio. I have been s ASE certified mechanic for almost 45 years. Theirs no set mileage for replacement.

There's plenty of room there for worn, serviceable operation that is less than optimal, most notably in the speed at which they do their job. Respect for the ASE certification, but I'd prefer to see literature confirming through reasonable testing that O2 sensors shouldn't be treated like spark plugs after so much use.
Good job on the chain job, I actually enjoyed doing mine. Hope you put premium parts on it in regards to not wanting to do the job again.

 

Understandable. Solid point. But the only wear item on an o2 sensor is the nose cone that's basically just a protective cover like a heat shield. I can't remember the GM service bulletin number but there has been extensive research showing them as non wear non serviceable parts. They either work or don't. As gar as speed of return is considered you sre talking about milliseconds. The ECM is designed to compensate for that miniscule of a reading by +or- .3. so in reality changing them is not going to rely be a factor that the ECM is going to use for sny charges. They are designed to send s reading so the air/fuel ratio is kept st 14 to 1.

 

there has been extensive research showing them as non wear non serviceable parts.

That is difficult to find and certainly not widely known, not to mention contrary to just about everything that would show up on the respectable offerings of the net when the subject matter is toggled. +/- .3 is approximately 30% of the measured voltage range and possibly even more by comparison if PCM programming is only designed to read a tighter boundary of the available voltage range, a small number with a large impact. PCM compensation is secondary to optimum sensor operation. +/- .3 is too much for me and probably contributes to the sensitivity many cars have to cheaper aftermarket sensors. Our Nissan had an upstream O2 sensor upgrade that required a PCM reflash for proper calibration so that 1 volt range isn't all that resilient it appears.
Lack of an owner's manual service recommendation just means there will be far fewer warranty related replacements. You've done a lot of work, may as well make it an academy award finish.

 

That was supposed to be .03
I saw it in one of the service bulletins when i was working at a dealership. Its been a few years. Wish i could remember the TO number.

 

I have been s ASE certified mechanic for almost 45 years.

Is there anybody else in this discussion that can make this claim?
If not, I suggest you withhold your remarks.

 

Most who work in technical fields understand learning is continuous.

 

Yes sir i have been turning wrenches just about all my life. Even in the Military. I had my own shop for awhile but insurance was so high here it was hard to make a decent living. I still have a lot of the old TO's here somewhere. I will see if i have the one I'm referencing. Everyone have a good day.🥃🥃

 

 

This is kinda what im talking about. The o2 is not a maintenance item because its not considered s wearable part. It either works or doesn't.
When it doesn't you replace it.
The only other time you really have to replace it is if you have exhausted all other avenues of repair and nothing is else can be found wrong. Then you may or may not need to replace it. Its basically like an old metering rod in the old quadra jet carbs. It determines the amount of fuil to air. The o2 just does it electric and through the ECM.

 

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I read that prior to my initial post here and my take from it is this; as a result of it not being listed as an item that needs to be replaced regularly (Operative word) like an air filter, or motor oil (usually less than 7k mile intervals), it is more likely to be overlooked and neglected and therefore should be kept in mind. That general statement goes on to stress that it is a critical component. No doubt you can find that same general statement copied and pasted in other poster's thoughts on the subject.

The O2 sensor is the nose of the car, In my understanding, the system is more dependent upon it for proper airfuel ratio than the MAF sensor. If it's out of calibration and doesn't set a code (they don't always), how will the PCM know this? Throwing parts at a car to solve a problem of that nature in regards to what you mentioned in the post above is what we'd all like to avoid.

I don't believe anyone has a real concern about your decision to continue to use the old sensors, just the suggestion that no benefit can be had from replacing them when the engine light is off and the mileage near one of the solar system planets.

 

What if you replaced your "perfectly good" O2 sensors and the fuel economy improved 1MPG on a 24-ish MPG car? Still argue there is no degradation over time?

I do agree that nobody really cares whether you replace them or not, but most here have done the exercise and seen, even measured, the before/after. I, for one, have faith in the scientific method and measured results. So disagree with your premise, as do I.

 

Lots of things affect fuel mileage. There could have been other factors that changed to cause an increase. Just because you changed them at that given time is not scientific proof that they're was a problem with them. I would be more concerned about why your car is only getting 24. I consistently average around 27 sometimes around 29. Just depends on conditions and the way i drive.

 

Yeah its kinda hard to do s lot of research when you are doing it for a living. Really don't have time to put much together. By the time i get off work hell and get home to take care of things there not much time for anything else. Im actually retiring December 1st. Im just wore out. Getting ready for my 8th major back surgery. Hell its been so long since i haven't hurt trying to work on these cars i can't even remember. But bills have to be paid. So glad my daughter is almost finished college. Maybe i will be able to do some good research soon.🥃🥃

 

Just finished doing the timing chains and all components including water pump, oil pump,etc.

Congrats on the timing set replacement! That is a very clean looking engine inside!

The o2 sensors are a work or don't work item.

Weeeeelll, no disrespect but yes if you mean they work as in either they return a resistance value that fluctuates or they don't. But there is such a thing as sensor accuracy, and it degrades over time and especially if AFR is consistently out of stoich. (rich)

Here's a link that talks about recalibrating O2's and O2 accuracy - full disclosure they are trying to sell you a product so... but there's a reason that tuners use expensive wideband sensors to adjust fuel mixtures and don't rely on the factory O2 readings...

Why do I need to calibrate the O2 sensor? - Racedom Blog

Innovate Motorsports is the first wideband O2 device manufacturer on the market that allows the user to field calibrate the O2 sensor. Our patented sensor

blog.racedom.com

It could be worthwhile to replace your O2's for a more accurate mixture and potentially better fuel efficiency. Of course depending on the price and what brand the replacements are there's no guarantee the new ones will be better than the old ones. So it really comes down to do they work "good enough" and like any other replacement part is the expense worth any potential increase in value or performance?

 

OK, folks-- we're done here.
What began as a very helpful thread has dissolved beyond the point of anything constructive with a few of you teetering on earning some vacation time.

Thread locked.