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JEEPTUBE
July 1st, 2006, 05:15
I was wondering when to replace the o2 sensors? Is there a specific milage?
Ive got a 97 and never replaced them.
I wonder if it will run more efficiantly with new ones in?
just a thought.:eeks1:

85xjwoody
July 1st, 2006, 05:42
I was wondering when to replace the o2 sensors? Is there a specific milage?
Ive got a 97 and never replaced them.
I wonder if it will run more efficiantly with new ones in?
just a thought.:eeks1:

It definitly would not hurt to replace them. Your mpg should get a little better. I have two 02 sensors and both need replacing badly. My mpg is under 10mpg. My engine is running very rich in my 96.

So yes, replace them.

Kim.

5-90
July 1st, 2006, 11:16
HEGO sensor life is generally taken to be about 80Kmiles, so you're probably due. The "pre-cat" sensor (if you have them before and after - most OBD-II do) is more important to fuel metering than the "after-cat," and also tends to wear out quicker (it's hotter.) The "after-cat" merely monitors catalytic converter performance, while the "pre-cat" provides feedback for the fuel metering system.

It's usually better to change them while hot, but BE CAREFUL! Also, the new sensor should come with never-seez on the threads - DO NOT CLEAN IT OFF! Just make sure that it hasn't got any on the sensor tip, and put it in.

I don't recall what size wrench it takes, but you can also get an "O2 Sensor Socket" at most parts houses that will fit, and will have a groove milled out of one side for the wiring, for a nominal fee. Should work on ANY HEGO sensor you run across, so it's not money wasted.

5-90

JEEPTUBE
July 1st, 2006, 15:29
OH HELL YES!!!

YMMV
July 1st, 2006, 19:57
There is no specific miles to replace an o2 sensor unless you're having concerns/problems. You can also use a scanner to monitor your o2 sensor to make sure its within spec. If it is, it would be pointless to replace it.

5-90
July 1st, 2006, 21:33
There is no specific miles to replace an o2 sensor unless you're having concerns/problems. You can also use a scanner to monitor your o2 sensor to make sure its within spec. If it is, it would be pointless to replace it.

Not quite. It's specified that the HEGO sensor is changed around 80Kmiles, but I've known them to go up to 130-150K or so without too many complaints.

In fact, I've still got the original unit in my 88 (still has the factory tag on it!) with 255Kmiles. I should probably change it tho - I'm starting to lose fuel mileage.

It's a bigger issue with later control systems tho - since they're more dependent upon feedback than earlier systems. I'm honestly surprised they haven't started using "wideband" HEGO sensors in wider applications - the "knuckle" or "narrowband" sensors in common use will tell you "rich" or "lean" - but the "wideband" sensor will not only tell you "rich" or "lean," but "how rich" or "how lean," and the system can be programmed for better adaptation - and more input can make control a little tighter and a little more solid - at the expense of maintaining change intervals and a more expensive sensor (about $300 vice $70 for the narrowband, but 100Kmiles is usually good for them. It also pays for itself in fuel mileage over the life of the sensor, so I'd consider it a good trade.)

You can check the heater element with a DMM to make sure it's good (since the heater allows it to go into "closed loop" control mode quicker,) but you'll need to get a code scanner or an interrogator to read sensor action.

5-90

lawsoncl
July 3rd, 2006, 12:58
I would not bother replacing the rear sensor unless you start getting error codes for it. It's just there to ensure the cat is working and doesn't affect how the engine runs.

JEEPTUBE
July 3rd, 2006, 14:54
YAH i replaced the back one last year because i was getting code. And figured i might as well replace the front one so it was complete. No performance gains though. But at least i dont have to worry when i take it to smog.:viking:

anony91xj
July 3rd, 2006, 15:11
Not quite. It's specified that the HEGO sensor is changed around 80Kmiles, but I've known them to go up to 130-150K or so without too many complaints.

In fact, I've still got the original unit in my 88 (still has the factory tag on it!) with 255Kmiles. I should probably change it tho - I'm starting to lose fuel mileage.

It's a bigger issue with later control systems tho - since they're more dependent upon feedback than earlier systems. I'm honestly surprised they haven't started using "wideband" HEGO sensors in wider applications - the "knuckle" or "narrowband" sensors in common use will tell you "rich" or "lean" - but the "wideband" sensor will not only tell you "rich" or "lean," but "how rich" or "how lean," and the system can be programmed for better adaptation - and more input can make control a little tighter and a little more solid - at the expense of maintaining change intervals and a more expensive sensor (about $300 vice $70 for the narrowband, but 100Kmiles is usually good for them. It also pays for itself in fuel mileage over the life of the sensor, so I'd consider it a good trade.)

You can check the heater element with a DMM to make sure it's good (since the heater allows it to go into "closed loop" control mode quicker,) but you'll need to get a code scanner or an interrogator to read sensor action.

5-90

O2 sensors are not a regular maintenance item. They should only be changed when they go bad, not just because they're old. My Grand Prix has 213,000 miles and the original O2 sensors, they still work fine.

Dude, he's got a 1997 with OBDII. Forget your "I hate self-diagnosing systems" attitude in modern times, especially with any vehicle made after 1996 (points and condensers are dead, move on...seriously). He can monitor everything with a shop scan tool, and if the O2 sensor(s) are out of spec, that will tell him. You are incorrect, a factory O2 sensor can tell how rich or how lean, it just doesn't have as wide a spectrum as a wideband O2 sensor...a factory O2 is confined to a much smaller voltage range. Unless you've got a turbocharged car or other performance application that requires VERY specific A/F readings, a wideband is pretty much unnecessary, that's why OEM's have not switched to them. Wideband sensors are expensive and not necessary in 99.9% of factory applications.

If the scanner shows all the O2 sensors reading within spec, there is NO REASON whatsoever to replace them and he'd be just wasting his money. Besides, if any of his O2 sensors were far enough out of spec to cause a problem, his Check Engine light would be on.

Seriously, I work in the modern auto repair industry. With OBDII, the best diagnostic tool a mechanic can have is a good scanner. Sure, DVOM's are still necessary, but in many instances, a Snap-On or OTC scanner makes diagnosis MUCH easier, a DVOM can often help confirm the diagnosis, or determine the difference between a sensor problem and wiring problem. Try working with a proper shop scanner and OBD vehicles, and your attitude towards them will change, I guarauntee it.

JEEPTUBE
July 3rd, 2006, 15:42
Like i said turd nugget. hahaha jk. i have a 97 and I have a scanner. And when my engine light came on, i scanned it and it said that my rear o2 sensor took a shite. And i have a freind that works at kragen so i got a good price on the o2 sensor on the header. So i bought it. It was just cheap insurance so i wouldnt have to worry about it not smogging or shitting out on me in the future. Other than that the engines tip-top.

5-90
July 3rd, 2006, 15:52
O2 sensors are not a regular maintenance item. They should only be changed when they go bad, not just because they're old. My Grand Prix has 213,000 miles and the original O2 sensors, they still work fine.

Dude, he's got a 1997 with OBDII. Forget your "I hate self-diagnosing systems" attitude in modern times, especially with any vehicle made after 1996 (points and condensers are dead, move on...seriously). He can monitor everything with a shop scan tool, and if the O2 sensor(s) are out of spec, that will tell him. You are incorrect, a factory O2 sensor can tell how rich or how lean, it just doesn't have as wide a spectrum as a wideband O2 sensor...a factory O2 is confined to a much smaller voltage range. Unless you've got a turbocharged car or other performance application that requires VERY specific A/F readings, a wideband is pretty much unnecessary, that's why OEM's have not switched to them. Wideband sensors are expensive and not necessary in 99.9% of factory applications.

If the scanner shows all the O2 sensors reading within spec, there is NO REASON whatsoever to replace them and he'd be just wasting his money. Besides, if any of his O2 sensors were far enough out of spec to cause a problem, his Check Engine light would be on.

Seriously, I work in the modern auto repair industry. With OBDII, the best diagnostic tool a mechanic can have is a good scanner. Sure, DVOM's are still necessary, but in many instances, a Snap-On or OTC scanner makes diagnosis MUCH easier, a DVOM can often help confirm the diagnosis, or determine the difference between a sensor problem and wiring problem. Try working with a proper shop scanner and OBD vehicles, and your attitude towards them will change, I guarauntee it.


I didn't say they HAD to be replaced at 80K - and I gave a couple examples of why not - I just said they SHOULD be replaced at 80K. It's what's recommended, not required.

Also, if you've read what I've written for any length of time, you'd understand that, in my mind, progress just for its own sake isn't usually. Sorry, but I've been doing this long enough to know that newer just ain't always better, and I've long believed that "technology should not replace skill." Besides, I know I've run across a few cases where OBD was wrong, and I was right - but try convincing anyone else of that. Besides, any system that makes it more difficult to actually IMPROVE things should be scrapped - there's nothing designed by the mind of man that can't be improved by the mind of man. That's my story and I'm stickin' to it. I prefer systems that are adaptable and NOT hidebound - which is why I prefer RENIX over OBD. That's not to say that I can't WORK on OBD when I have to - but I'd prefer not to own it.

I'm not going to come out and say that points/condenser and a carburettor is going to be better - it's not. But, let's stop overhauling things just for its own sake - and it should also be borne in mind that legislation cannot effectively drive innovation and useful improvements, no matter WHAT Congress things (and the EPA, and ... ad mauseum. Legislators and rulemakers, like lawyers and accountants, simply have NOTHING useful to contribute to engineering, and they just don't realise it.)

And, WHEGO sensors are starting to be used in some applications - most of the literature I've found of a technical nature is put out by Toyota training - which, likely, means it's OEM. This is a case of something "new" that is also "useful" - it's like anything else with a number, it's useless if it can't be quantified properly.

And, as far as the "I hate self-diagnosing systems," it's probably because I came up using systems where I actually had to do the troubleshooting and "grey matter" work on my own, and I don't see any reason to stop doing so. Pardon me for saying so, but it almost takes a combination between an idiot and a EET major to work on vehicles these days, and I am neither. And, of course, with the strictures laid down by OBD-II these days, it's damn near impossible to modify things to make them run BETTER, and some systems on OBD are needlessly complex - and can probably be replaced with "technology" devised 50 years ago, and be more reliable and more effective to boot!

And, I have worked with a "proper shop scanner" (Snap-On MT2500 with "all the fruit," in fact,) and OBD vehicles. The problem there is that the tools needed to work on OBD are gradually getting out of reach of the hobbyist, which is also a great mistake. I don't care for ANYTHING that isn't field serviceable, diagnosible with a minimum amount of equipment (sometimes knowledge is enough,) and that you can't improvise a repair on until you get back to civilisation to fix it properly. I know that OBD has a "Limp Home" mode programmed into it, but it just KILLS performance and efficiency, which tells me that it's not programmed well. An improvised repair isn't going to be as good as a proper repair, but it should be pretty damn close, if you know what you're about.

As far as NHEGO vice WHEGO, the NHEGO may be able to tell you "how" rich or lean, but from what I've seen of the voltage output curve, it's a VERY narrow range, and that gives the signal little utility. It falls off the scale rapidly outside the range of, as I recall, 12.5:1 to 16:1AFR (ish,) and it spends a lot of time "bouncing" trying to get back into that range. WHEGO sensors will give you an accurate and useful reading from, say, 4:1 to about 25:1AFR, which becomes a lot more useful to someone who properly designs a feedback system. In fact, using WHEGO sensors could probably obviate a number of other systems, if they'd think to apply them properly (lowering TCO and aggregate system production costs.)

Sorry, but I'm not buying it. I'll grant that OBD would be more useful if unqualified individuals and organisations would stay out of the design process (I've very rarely met a lawmaker or a regulation writer that actually KNEW ANYTHING about the subject matter at hand at the moment!) but until that happens, I don't see anything to like about OBD-I, OBD-II, or the proposed OBD-III.

That's my story and I'm stickin' to it!

5-90

lawsoncl
July 3rd, 2006, 15:58
You are incorrect, a factory O2 sensor can tell how rich or how lean, it just doesn't have as wide a spectrum as a wideband O2 sensor...a factory O2 is confined to a much smaller voltage range.

But the computer doesn't actually use that voltage range. It looks for voltages above or below the threshold, with some hysteresis, and calls it lean or rich. The typical narrow-band O2 sensor is not accurate enough or consistent enough between sensors to determine the true a/f ratio.


Unless you've got a turbocharged car or other performance application that requires VERY specific A/F readings, a wideband is pretty much unnecessary, that's why OEM's have not switched to them. Wideband sensors are expensive and not necessary in 99.9% of factory applications.

I'd agree with that. However, consider that auto makers are now starting to look at wide-band sensors as they try to get reliable lean-burn engines. I think maybe thats what 5-90 meant. The a/f ratio determined by a typical narrow band sensor is not ideal. Its a compromise of decent power and economy.


If the scanner shows all the O2 sensors reading within spec, there is NO REASON whatsoever to replace them and he'd be just wasting his money. Besides, if any of his O2 sensors were far enough out of spec to cause a problem, his Check Engine light would be on.

I don't believe thats true. A contaiminated, fouled or eroded O2 sensor will have a slower response time and the voltage point may shift up or down. Neither will trigger the check engine light so long as the sensor is still cycling and not stuck at a high or low voltage. OBD-II has a better chance of catching it with the rear O2 sensor as a sanity check, but even that' s not foolproof. Just search this group for examples of folks with crappy mileage and no check engine light, who solved the problem by changing the O2 sensor 9yea most are Renix or ODBI). If you're getting unexplained crappy mileage and your O2 sensor is ancient, replacing the sensor would be reasonable.


Seriously, I work in the modern auto repair industry. With OBDII, the best diagnostic tool a mechanic can have is a good scanner. Sure, DVOM's are still necessary, but in many instances, a Snap-On or OTC scanner makes diagnosis MUCH easier, a DVOM can often help confirm the diagnosis, or determine the difference between a sensor problem and wiring problem. Try working with a proper shop scanner and OBD vehicles, and your attitude towards them will change, I guarauntee it.

Yes, good scanners are a great asset. I also feel that basic diagnostic skills and knowing how to use a DVM are what seperate a shop mokey from a good mechanic. Too many times I see people who have gone to a shop and the guy is helpless without his diagnostic scanner. A good mechanic can look at the symptoms and have a good idea where to start before he even gets the scanner out. A poor mechanic believes everything the scanner says.

JEEPTUBE
July 3rd, 2006, 16:10
What are u guys blabbin about.
Engine runs like shit.
Engine light comes on.
Scan it, read it,fix it.
o2 sensor rear bank gone poopoo.
replace.
engine light goes away.
engine runs tip top again.
YAY!!

As far as replacing the front one.
I didnt have to. But i did. It was cheap.
So why are u guys still arguing?
HEHEHHEE HAHA AHAE H E.....heheh. :kissyou:

JEEPTUBE
July 3rd, 2006, 16:19
LAWSON,
that is so true about the scanners and the turds that totally rely on them to find the prob. My girl and i were running up to grassvalley to pick up my t-case. Her tranny was acting all weird and fluctuation hunting or something. So we had the dude were i picked up the t-case scann it. And he said were ****ed and that we have to replace the tranny. He was saying yah leave it here. And i said no thanks. so i took my t-case and left. Took it to chevy and they said it was low on tranny fluid. That was 3 years ago. And the tranny never did that again.

sw_mi_xj
July 3rd, 2006, 16:25
THEORY !!!!
and i would consider this a discussion , not quite an argument yet .

overly complex isnt progress , but try to tell the epa that " we dont need no stinkin o2 sensors " . not happening .

anony91xj
July 3rd, 2006, 16:27
The problem there is that the tools needed to work on OBD are gradually getting out of reach of the hobbyist, which is also a great mistake. I don't care for ANYTHING that isn't field serviceable, diagnosible with a minimum amount of equipment (sometimes knowledge is enough,) and that you can't improvise a repair on until you get back to civilisation to fix it properly. I know that OBD has a "Limp Home" mode programmed into it, but it just KILLS performance and efficiency, which tells me that it's not programmed well. An improvised repair isn't going to be as good as a proper repair, but it should be pretty damn close, if you know what you're about.

Yes, OBDI caused these problems. Not so with OBDII, and that was part of the reason it was standardized. Anyone can go to AutoZone or even WalMart now and buy a generic OBDII scanner of some sort that can read error codes. Combine that with a DVOM (a good DVOM will cost a LOT more than a OBDII scan tool), and you should be able to diagnose anything in the field. Granted, it'd often be hard to fix without replacement parts, but diagnosis is quite possible. That's where the "limp home" mode comes in. If you can't fix it in the field, you can still get home, albeit with less efficiency, power, etc. Different manufacturers use different types of "limp home" programming, some are worse than others.



I'd agree with that. However, consider that auto makers are now starting to look at wide-band sensors as they try to get reliable lean-burn engines. I think maybe thats what 5-90 meant. The a/f ratio determined by a typical narrow band sensor is not ideal. Its a compromise of decent power and economy.

Not ideal, but good enough. The cost of a wideband, plus the programming for it, wouldn't be worth it for most consumers. People who post on car forums (regardless of make or model) are generally not the average car buyer.


I don't believe thats true. A contaiminated, fouled or eroded O2 sensor will have a slower response time and the voltage point may shift up or down. Neither will trigger the check engine light so long as the sensor is still cycling and not stuck at a high or low voltage. OBD-II has a better chance of catching it with the rear O2 sensor as a sanity check, but even that' s not foolproof. Just search this group for examples of folks with crappy mileage and no check engine light, who solved the problem by changing the O2 sensor 9yea most are Renix or ODBI). If you're getting unexplained crappy mileage and your O2 sensor is ancient, replacing the sensor would be reasonable.

Renix provided no codes, and OBDI was iffy at best when it comes to throwing codes. If you watched the datastream from either with a bad O2 sensor, you should see that it's out of spec.

OBDII does have codes for the condition you're describing, I forget the numbers offhand but it's called "O2 Sensor Bank X Sensor X SLow Response".


Yes, good scanners are a great asset. I also feel that basic diagnostic skills and knowing how to use a DVM are what seperate a shop mokey from a good mechanic. Too many times I see people who have gone to a shop and the guy is helpless without his diagnostic scanner. A good mechanic can look at the symptoms and have a good idea where to start before he even gets the scanner out. A poor mechanic believes everything the scanner says.

A good mechanic needs both a scan tool and DVOM to work on modern cars. Once an error code is thrown by the PCM, the scanner can identify the code. Sometimes the datastream on the scanner is all that's needed to diagnose and repair the code. Other times, a DVOM is necessary to diagnose further...it's not uncommon to get a code that could be caused by a bad sensor or a broken wire between whatever sensor and the PCM. It takes a skilled mechanic to connect the scanner's information to the actual problem. A "shop monkey" will read the code and just throw a sensor or some parts at the problem, hoping to fix it...then get shot in the ass when the car comes back with the problem not fixed.

JEEPTUBE
July 3rd, 2006, 17:02
Its all a huge CONSPIRACY!!!!!

5-90
July 3rd, 2006, 21:35
Very well, then how should we go about correcting the "Zimbu the Monkey" syndrome? There's a reason that there are only three mechanics in the country I trust - and I'm the only one in CA. Frankly, I find that most "mechanics" out here aren't worth a damn, much less the moniker "mechanic."

As far as using WHEGO - maybe it's out of reach for the hobbyist or the "one-off" system designer, but there's no reason whatever that OEMs couldn't use it, design a system to use it, and simplify fuel metering and control thereby. Besides, fewer parts = fewer potential sources of failure. Now, THAT is good design!

As far as cost, most OBD-II readers I've seen (geared toward the hobbyist) runs in the $150-300 range, while a decent DMM can run ~$100, unless you're going to get a Fluke or something similar (I've got an old Fluke DMM that ran me about $800 when I got it, but it offered precision I needed at the time. No, it wasn't for automotive troubleshooting, but that's what it gets used for now. I've got a $100 unit that I got at Sears that serves well in the field, where the Fluke doesn't go.) In fact, there's no reason at all that you shouldn't be able to get a decent DMM for $50-100, unless you insist upon a Fluke or a Beckman Industrial, or you REALLY want a VTVM (most people reading this have probably never SEEN a VTVM - I think I still HAVE one somewhere... Damn thing cost me $150 'way back when.)

RENIX may be pre-OBD and does not provide codes, but that's not even a stumbling block to a true mechanic (Zimbu the Monkey would be well past stuck. Witness what us RENIX owners go through around Smog Check time...)

Speaking of standardisation, if OBD-II is so damn standard, why are there so many part numbers for sensors that do the SAME DAMN THING?!? Why aren't there, say, three or four standard sensor part numbers to make things so much easier for the service techs? HEGO sensors are all the same size, there's no reason for MAP sensors to be the same, and IAT and CTS sensors are sometimes THE SAME DAMN PART - so why not go industry-wide with standard parts? Yet another complaint I have about later designs is that, while the system itself may be standard, the parts are actually NOT, and that just drives up the prices until your "parts budget" becomes useless for little more than lunch money... There is nothing at all wrong with the idea of a hobbyist mechanic - things will get fixed a lot quicker (minor stuff, anyhow) if you don't have to deal with onerous labour bills...

Riddle me THAT.

5-90

lawsoncl
July 3rd, 2006, 22:45
As far as cost, most OBD-II readers I've seen (geared toward the hobbyist) runs in the $150-300 range, while a decent DMM can run ~$100,

I've got a handful of Harbor Freight meters that I got on sale for $5 that are fairly loaded with features and reasonable precision. I keep one in each car and my desk at work. I have an old analog meter in the garage which is great for testing things like TPSs where you can see if the needle moves smoothly. I have a nice $150 meter on the electronics bench that has LCR, freq, etc. Sometimes I even break out the o-scope for checking things like abs and tranny speed sensors. I see no excuse for someone trying to work on their vehicle not to have even a low end DVM like the $20 one from Sears. Of course I take it for granted that most people don't understand electronics.

OBD-II standardized a lot of the data and protocols which I think really helped the bring down the price of aftermarket code readers. Of course they still didn't standardize the actual interface so you still have three different hardware interfaces to deal with. Don't worry OBD-III will have mandatory gps and remote backdoors so the cops can track you and disable your vehicle remotely. :}

I agree that it would be nice to see more commonality in part numbers, specs and connectors, but alas each manufacturer likes to have their own numbers. At least they are starting to be common across a single manf and NAPA can still cross to a generic even if you have to swap the connector yourself.

Can I quote you on "Zimbu the Shop Monkey"

5-90
July 3rd, 2006, 23:59
I've got a handful of Harbor Freight meters that I got on sale for $5 that are fairly loaded with features and reasonable precision. I keep one in each car and my desk at work. I have an old analog meter in the garage which is great for testing things like TPSs where you can see if the needle moves smoothly. I have a nice $150 meter on the electronics bench that has LCR, freq, etc. Sometimes I even break out the o-scope for checking things like abs and tranny speed sensors. I see no excuse for someone trying to work on their vehicle not to have even a low end DVM like the $20 one from Sears. Of course I take it for granted that most people don't understand electronics.

OBD-II standardized a lot of the data and protocols which I think really helped the bring down the price of aftermarket code readers. Of course they still didn't standardize the actual interface so you still have three different hardware interfaces to deal with. Don't worry OBD-III will have mandatory gps and remote backdoors so the cops can track you and disable your vehicle remotely. :}

I agree that it would be nice to see more commonality in part numbers, specs and connectors, but alas each manufacturer likes to have their own numbers. At least they are starting to be common across a single manf and NAPA can still cross to a generic even if you have to swap the connector yourself.

Can I quote you on "Zimbu the Shop Monkey"


The data protocols may be standard, but (as you mentioned,) the hardware interfaces are different (and not just the "Big 3" - aren't Toyota, Honda, and Nissan also on different hardware bus standards?)

I have heard (a few times,) that OBD-III is supposed to have onboard emissions monitoring with the ability to cut out the engine if emissions exceed a certain level. Granted, I'm not anything like certain that isn't just bogon emissions, but it's the sort of thing the EPA would like to sneak in anyhow... Just imagine if someone is trying to get out of the way of a large truck, and sticks their foot in the skinny pedal - which means that HC and CO are going to spike significantly...

One thing that OBD-III damn sure SHOULD carry is standardisation of parts, just to simplify matters. It ain't gonna happen, but I'd like to see it. Also, perhaps, allow for easier diagnosis WITHOUT the "onboard" part - but I'm definitely talking through my hat here - that is certainly NOT going to happen. Once they come up with a complex system, it don't get any simpler (just look at government itself - it just don't happen. Entropy at work, I am inclined to think...)

Of course, with all the "blue sky" goals of OBD that the government would like to see, there's no way on Gawd's Green Earth that I'm going to buy anything past OBD-II (and, I have a hard time with the idea of a POV made past 1995 now...) Unlike everyone else, who are so used to having cell phones and such, and being in contact all the time - I actually LIKE to "fall off the scope" once in a while. I still like to get lost in the woods about once a year - just me and about 10 pounds of kit, live off the land, and get my mind right for the next year. It helps.

The more that technology tries to take that away from me, the more I'm going to need to go do it. Backlash, maybe. I damn sure don't want my vehicle to report on my whereabouts whenever I run out for pizza - it's Nobody's Damn Business But Mine.

5-90

Oh - go ahead and quote "Zimbu the Monkey" - it's a little more generic. I also use it when referring to room-temperature IQ tasks or jobs - "I could teach Zimbu the Monkey to do that in about five minutes..."

5-90

JEEPTUBE
July 4th, 2006, 00:11
WORD!

5-90
July 4th, 2006, 00:45
WORD!

Awright - now what are YOU on about! :confused1 Am I missing something?

Just kidding, and just checking...

5-90

JEEPTUBE
July 4th, 2006, 01:55
just a agreeing wyrm.

5-90
July 4th, 2006, 12:54
just a agreeing wyrm.

Just checking - I never did pick up on "street speak," or whatever it's called this week. I've got enough to keep in my hat as it is...

5-90

lawsoncl
July 4th, 2006, 14:31
The data protocols may be standard, but (as you mentioned,) the hardware interfaces are different (and not just the "Big 3" - aren't Toyota, Honda, and Nissan also on different hardware bus standards?)


You're right. I checked and there is CAN, ISO, KWP, VPW, and PWM. Starting in 2008, cars sold in the US will be required to use the CAN bus interface (actually a varient of CAN). http://en.wikipedia.org/wiki/OBD-II.

5-90
July 4th, 2006, 14:36
Excellent. Maybe now that we're standardising the data stream, we can begin to standardise the data SOURCES, and cut down on the part numbers needed. I thought that was what standardisation was...

5-90

tugalo
July 5th, 2006, 10:38
I agree with 5-90....engineers have a tendency to design ELEGANT devices, sometimes ELEGANCE does not equate to EFFECTIVE...

XJ Eric
July 5th, 2006, 13:14
Umm, so there are only 2 O2 sensors right? I'm getting the code saying that bank one sensor two has high voltage. That means the sensor sticking out of my cat right?

lawsoncl
July 5th, 2006, 20:21
Umm, so there are only 2 O2 sensors right? I'm getting the code saying that bank one sensor two has high voltage. That means the sensor sticking out of my cat right?

Yes. The ODB-II codes include the provision for more than 1 bank, such as a V8 with dual exhaust.

RandyD71
July 5th, 2006, 21:03
To answer the question about the size of the O2 sensors. It would be 7/8" or its metric equivolent of 22mm for 90% of the vehicles out there. A lot of the other 10% are Toyotas and will probably ise 2 studs with 12mm nuts holding them in place.
5-90 is right that the newer WHEGO sensors are more accurate than the old HEGO sensors which are better than the reaaly old EGO. You remember the old 1 wire ones that cost all of $20. Honda and Toyota are 2 OEMs using WHEGO sensors, but they call them Air/Fuel Ratio Sensors instead of osygen sensors and they cost a ton.
Some of the people that are involved in writing the laws concerning emissions laws and regulations due know what they are talking about. My instructor for my Emissions License had a lot to due with PA's Enhanced Emissions Inspection Certifacation program. He gave me a great tip that I will share with you guys. On a lot of newer(OBD-II) vehicles when you have a P0420 Catalyst Efficiency code present there are two primary causes that are not the cat and they cover 95% of the vehicles. Make sure there is no exhaust leak present because it will give a false reading and secondly change the downstream O2 sensor as it at the end of its service life and is giving a false reading. Has not been wrong about it in over 30 changes of O2 sensors so far.
Finally, scanners are great. I use Modis myself, but they are only as smart as the monkey operating it.