Oxygen Sensors: Is it really worth it?
avatar307
10-31-2004, 10:58 PM
They say replacing Oxygen Sensors not only help protect the environment, but will increase your fuel economy.
I have yet to find the manufacturer recommended interval for replacement, but on-line I've been seeing "when you change your spark plugs" and "every 30,000 miles.
I have a 1995 LeSabre with 175,000 miles on it. It requires TWO Heated O2 sensors, $50/each. (One in the rear manifold and one after the catalytic converter.)
I'm planning to replace the PCV valve next week, as it's a $3 part and I can't find the maintenance interval on it either. Oxygen Sensors though... Is it really worth the $100?
I have yet to find the manufacturer recommended interval for replacement, but on-line I've been seeing "when you change your spark plugs" and "every 30,000 miles.
I have a 1995 LeSabre with 175,000 miles on it. It requires TWO Heated O2 sensors, $50/each. (One in the rear manifold and one after the catalytic converter.)
I'm planning to replace the PCV valve next week, as it's a $3 part and I can't find the maintenance interval on it either. Oxygen Sensors though... Is it really worth the $100?
sierrap615
11-01-2004, 11:59 PM
most people say when the O2 sensor goes bad is when it need replaced, but on a high mileage car like yours, if it is still the original O2 go ahead and replace the front O2. the front O2 is used for the A/F mixture, the rear O2 only monitors the cat to ensure its working, it does not alter the performance of the car.
buickmastermind
11-02-2004, 11:04 AM
To my knowlegde, as long as the exhaust is not black and the car runs smooth, there isn't a problem with either of the O2 sensor.
avatar307
11-02-2004, 12:21 PM
Oh, I'm not asking if it's broken. I'm asking if replacing a 9 year old 02 sensor will help my gas milage enough to justify the $50.
The fact is, if it was busted, my check engine light would light up immediately. Far before the engine was running rich enough to make black smoke or lean enough to sputter.
Think of it this way. I only recently changed the factory original Bosch spark plugs in the car. There was no filiment left on any of them, and their gap was over .075 instead of .060. However, I didn't change them because of car problems. The car ran perfect, started right up, never hesitated or sputtered, and never lit the check engine light.
The spark plugs still needed changed though, and changing them gave me a 3-5 MPG increase (not suprisingly). Would changing a functional but old O2 sensor have an equivelent effect?
Or would the increases in effiecency not justify spending another $50 on a car that will probably be retired in a couple years. (Actually, that's not even part of it. I expect I'll drive this car until it completely quits, even if I buy another car.)
sierrap615- Thanks for the info. That's what I thought. I have been debating only replacing the front sensor, as it is responsible for more engine functionality. Knowing my Cat is working is great, but the car doesn't need a $50 O2 sensor to know that.
My only worry would be that if I replace the O2 sensor in the manifold, that I'll have to replace the O2 sensor behing the Cat because the readings don't match. I assume the car makes sure the Cat is working by comparing the reading from that O2 sensor with the one in the manifold.
If I replace only one of the sensors, it might cause the readings to be far enough out of alignment to trigger my check engine light, and that is REALLY going to annoy me.
(Similarly. I'm currently repairing my air bag system. Not because I think I will need them, or particurally want to deal with the expense caused by them every deploying. But rather, the freaking light on my dash board is on all the time and it aggrivates the hell out of me.)
The fact is, if it was busted, my check engine light would light up immediately. Far before the engine was running rich enough to make black smoke or lean enough to sputter.
Think of it this way. I only recently changed the factory original Bosch spark plugs in the car. There was no filiment left on any of them, and their gap was over .075 instead of .060. However, I didn't change them because of car problems. The car ran perfect, started right up, never hesitated or sputtered, and never lit the check engine light.
The spark plugs still needed changed though, and changing them gave me a 3-5 MPG increase (not suprisingly). Would changing a functional but old O2 sensor have an equivelent effect?
Or would the increases in effiecency not justify spending another $50 on a car that will probably be retired in a couple years. (Actually, that's not even part of it. I expect I'll drive this car until it completely quits, even if I buy another car.)
sierrap615- Thanks for the info. That's what I thought. I have been debating only replacing the front sensor, as it is responsible for more engine functionality. Knowing my Cat is working is great, but the car doesn't need a $50 O2 sensor to know that.
My only worry would be that if I replace the O2 sensor in the manifold, that I'll have to replace the O2 sensor behing the Cat because the readings don't match. I assume the car makes sure the Cat is working by comparing the reading from that O2 sensor with the one in the manifold.
If I replace only one of the sensors, it might cause the readings to be far enough out of alignment to trigger my check engine light, and that is REALLY going to annoy me.
(Similarly. I'm currently repairing my air bag system. Not because I think I will need them, or particurally want to deal with the expense caused by them every deploying. But rather, the freaking light on my dash board is on all the time and it aggrivates the hell out of me.)
csaxon
11-02-2004, 02:14 PM
http://www.boschusa.com/AutoParts/OxygenSensors/PremiumOxygenSensors/
http://www.boschusa.com/AutoParts/Promotions/GasCard/
This might help recover some of the cost.
http://www.boschusa.com/AutoParts/Promotions/GasCard/
This might help recover some of the cost.
avatar307
11-02-2004, 02:49 PM
*doh* Already replaced my spark plugs... Now who do I know who needs spark plugs...
sierrap615
11-03-2004, 02:04 AM
oh no. not the damn platinums again....
first, there is no gain. the resistance of the ignition system is so much puting a thin coat of platinum on the tips doesn't do a thing, if anything, it increases resistance because its another part it need the transfer threw. second, the 4+, that plug has so many tips the air/fuel mixture can't flow completey into the spark. third, oil destorys the platinum. last, they are known to cause missfires.
i've tested platinums on an ignition scope, didn't see a single difference. plus with platinum costing $835 per pound, how much can really be on a $5 plug?
but really if the platinums work is hit or miss as per each car. but several manufactiors have put out TSBs on them
first, there is no gain. the resistance of the ignition system is so much puting a thin coat of platinum on the tips doesn't do a thing, if anything, it increases resistance because its another part it need the transfer threw. second, the 4+, that plug has so many tips the air/fuel mixture can't flow completey into the spark. third, oil destorys the platinum. last, they are known to cause missfires.
i've tested platinums on an ignition scope, didn't see a single difference. plus with platinum costing $835 per pound, how much can really be on a $5 plug?
but really if the platinums work is hit or miss as per each car. but several manufactiors have put out TSBs on them
sierrap615
11-03-2004, 02:20 AM
I'm asking if replacing a 9 year old 02 sensor will help my gas milage enough to justify the $50.
i honsity could not tell you that without hooking up several grand worth of equitment.
i know you've been doing some work with the OBD system, do you have a datastream scanner?
or a multimeter?
i replace mind this year, i beleave it was still orginal(10 years, 165K miles) car ran a little smoother, a bit better gas mileage(but did a few other things too)
in your case i would change it if you have a spare $50, i can't say if you will get it back. if you can't do any other test, remove and visiually inspect the O2 (the main cause of failure IMO is being coated by fuel/oil/coolent/ect...)
i honsity could not tell you that without hooking up several grand worth of equitment.
i know you've been doing some work with the OBD system, do you have a datastream scanner?
or a multimeter?
i replace mind this year, i beleave it was still orginal(10 years, 165K miles) car ran a little smoother, a bit better gas mileage(but did a few other things too)
in your case i would change it if you have a spare $50, i can't say if you will get it back. if you can't do any other test, remove and visiually inspect the O2 (the main cause of failure IMO is being coated by fuel/oil/coolent/ect...)
avatar307
11-03-2004, 09:02 AM
I agree with you on Plantiums. The only reason I'd ever allow myself to install them in a car is an assumption that they would last longer. Even then though... I don't think I could make myself spend the extra money knowing it's BS. As with everything it came down to money. So I compromised, and bought the ones in between, copper split fires.
Anyway, back to O2 sensors. I do have a multimeter, and I think I have the procedure for checking the functionality of an O2 sensor nearby. I'm sure the O2 sensors are working, my only concern is how well. If I replaced the one with a new one, it would follow the new one would work better, and thus the assumption is fuel economy should increase.
As far as a data stream scanner. 1) Nope, don't own one, don't really need one, so I can't justify the money. If I get one, I'll build my own microporcessor equipped little adapter and use my computer.
2) Even if I did own one, I couldn't hook it up to my LeSabre as of current. Problem is my 95 LeSabre's 16-pin OBD-II style connector conforms neither to OBD-II nor GM's pre-OBD-II "'OBD-I' using the OBD-II connector" pin out. My current guess is that my car is OBD-II, the pins are just in the wrong place. But without borrowing someones OBD-II scanner for a couple hours to play with the pins, I can't know which of 9 and 14 goes to 2.
(Pretty sure it's not OBD-I though. -- I've been through every possible pin cross and never accomplished flashing the SES light. The car has a PCM, via visual inspection. And everything else falls in the "late-1995 model." It has several additions that weren't fully integrated until 1996, but my 1995 has them. Such as the radio and wiring harness.)
Without the full factory wiring diagrams, I really can't know anything. Currently shopping for a factory service manual.
Anyway, back to O2 sensors. I do have a multimeter, and I think I have the procedure for checking the functionality of an O2 sensor nearby. I'm sure the O2 sensors are working, my only concern is how well. If I replaced the one with a new one, it would follow the new one would work better, and thus the assumption is fuel economy should increase.
As far as a data stream scanner. 1) Nope, don't own one, don't really need one, so I can't justify the money. If I get one, I'll build my own microporcessor equipped little adapter and use my computer.
2) Even if I did own one, I couldn't hook it up to my LeSabre as of current. Problem is my 95 LeSabre's 16-pin OBD-II style connector conforms neither to OBD-II nor GM's pre-OBD-II "'OBD-I' using the OBD-II connector" pin out. My current guess is that my car is OBD-II, the pins are just in the wrong place. But without borrowing someones OBD-II scanner for a couple hours to play with the pins, I can't know which of 9 and 14 goes to 2.
(Pretty sure it's not OBD-I though. -- I've been through every possible pin cross and never accomplished flashing the SES light. The car has a PCM, via visual inspection. And everything else falls in the "late-1995 model." It has several additions that weren't fully integrated until 1996, but my 1995 has them. Such as the radio and wiring harness.)
Without the full factory wiring diagrams, I really can't know anything. Currently shopping for a factory service manual.
avatar307
11-03-2004, 09:07 AM
Speaking of Oxygen Sensors. Here's a little pig-tail so you can splice into the sensor haness and monitor the air/fuel mix from a guage in the passenger compartment.
My god... some people have too much time... or is it money... I can't remember. I'll probably end up with one one day 5 years from now. I love gauges and read-outs... I'm not buying a new car until I can have a customizable touch screen computer and heads up display included. ROFL
http://www.intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=TEC-AFP&Category_Code=IE
My god... some people have too much time... or is it money... I can't remember. I'll probably end up with one one day 5 years from now. I love gauges and read-outs... I'm not buying a new car until I can have a customizable touch screen computer and heads up display included. ROFL
http://www.intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=TEC-AFP&Category_Code=IE
buickmastermind
11-03-2004, 10:09 PM
(not to get off topic) I think it's kind of funny. Platnum is a great conductor of electricty, but doesn't do a thing for a spark plug. Interesting how that works.
Just out of curiosity, what is your current average MPG? If your driving trips (mostly) are less that 40 miles, with stops along the way, you should be averaging no less than 22 mpg. If your trips are 40+ miles with few or no stops, then you should be looking at about 25-29 mpg. If MPG is less than that, the sensor will pay for itself shortly, especially at $2+ per gal. of gas, depending on how much driving you actually do. I think that both the 3800 and the series II have the same gas mileage.
I am sure there is a web-site that can tell you how to make an adapter between the two OBD II style connectors, and they should have wiring diagrams as well. I think (not sure, as I might be confusing this with something else) that you can also build an adapter for it.
Just out of curiosity, what is your current average MPG? If your driving trips (mostly) are less that 40 miles, with stops along the way, you should be averaging no less than 22 mpg. If your trips are 40+ miles with few or no stops, then you should be looking at about 25-29 mpg. If MPG is less than that, the sensor will pay for itself shortly, especially at $2+ per gal. of gas, depending on how much driving you actually do. I think that both the 3800 and the series II have the same gas mileage.
I am sure there is a web-site that can tell you how to make an adapter between the two OBD II style connectors, and they should have wiring diagrams as well. I think (not sure, as I might be confusing this with something else) that you can also build an adapter for it.
sierrap615
11-04-2004, 12:28 AM
you buy the OBD1 connector allong with a handful of others when you buy a expencive scanner. i myself am thinking about following avatar's idea of getting a OBD2 connector from a junkyard and fitting it on my car.
avatar307
11-05-2004, 01:53 PM
My MPG is about 19 City (with long stop lights, braking, and hard accells), 23 Highway. That's up 3-5 MPG from what it was before I changed the spark plugs, ROFL. (I saved the old ones because they were so... no longer spark plugs.)
As far as my connector. There is no website detailing it, there are only MAYBE two people I have ever found with a similar connector. (And I have looked high and low.)
I have read more documents on the subject than is healthy. I have 20+ pages to hand drawn pin outs, voltages, ohm readings, wiring diagrams. Still waiting on copies from a factory service manual to proceed with rewiring and/or building my own adapter.
See my recent three page post:
http://www.automotiveforums.com/vbulletin/showthread.php?t=307153
As far as I can tell, they only exist in 1995 C/H-bodies, and perhaps only those built in Flint. I believe there was mention of an adapter used once, but I never got the name of the adapter for reference.
It is not the OBD-I in 16-pin connector. I have pin outs for those (they were used in 1995 S-10s and such) and it is not the same connector. I have also run every permetation of shorting pins, none result in OBD-I style diagnosics. (The 1995 LeSabre is listed as having a PCM, not and ECM. That implies OBD-II.)
With a OBD-II tester and a few hours, I could have it solved. Or with a wiring diagram, I could build an adapter before hand. Or I could build a couple adapters as I'm pretty sure I know which wires need to go where.
I just haven't done it yet. This specific project is more of a hobby. So I work on it when I'm motivated to work on it, and prepared to be late to work for a week because of it.
Anyway, for simplicy and everyones understanding, these are the types of connectors I have identified:
1) "OBD-I" using the ALDL/12-pin connector
2) "OBD-I" using the 16-pin SAE J1962 connector (same as the OBD-II connector)
3) OBD-II (VPW,PWM,CAN,&ISO) using the J1962/16-pin connector
4) Unknown (probably early OBD-II experiment) using the J1962/16-pin connector
I have pin outs for all but the last, which is the on on my 1995 LeSabre Custom, Engine VIN code L, manufactured in Flint, MI, 4xx,xxx serial number range.
As far as my connector. There is no website detailing it, there are only MAYBE two people I have ever found with a similar connector. (And I have looked high and low.)
I have read more documents on the subject than is healthy. I have 20+ pages to hand drawn pin outs, voltages, ohm readings, wiring diagrams. Still waiting on copies from a factory service manual to proceed with rewiring and/or building my own adapter.
See my recent three page post:
http://www.automotiveforums.com/vbulletin/showthread.php?t=307153
As far as I can tell, they only exist in 1995 C/H-bodies, and perhaps only those built in Flint. I believe there was mention of an adapter used once, but I never got the name of the adapter for reference.
It is not the OBD-I in 16-pin connector. I have pin outs for those (they were used in 1995 S-10s and such) and it is not the same connector. I have also run every permetation of shorting pins, none result in OBD-I style diagnosics. (The 1995 LeSabre is listed as having a PCM, not and ECM. That implies OBD-II.)
With a OBD-II tester and a few hours, I could have it solved. Or with a wiring diagram, I could build an adapter before hand. Or I could build a couple adapters as I'm pretty sure I know which wires need to go where.
I just haven't done it yet. This specific project is more of a hobby. So I work on it when I'm motivated to work on it, and prepared to be late to work for a week because of it.
Anyway, for simplicy and everyones understanding, these are the types of connectors I have identified:
1) "OBD-I" using the ALDL/12-pin connector
2) "OBD-I" using the 16-pin SAE J1962 connector (same as the OBD-II connector)
3) OBD-II (VPW,PWM,CAN,&ISO) using the J1962/16-pin connector
4) Unknown (probably early OBD-II experiment) using the J1962/16-pin connector
I have pin outs for all but the last, which is the on on my 1995 LeSabre Custom, Engine VIN code L, manufactured in Flint, MI, 4xx,xxx serial number range.
buickmastermind
11-05-2004, 05:10 PM
I would be expecting better hyway mileage, so there may be a bad sensor. If your mileage is that low when going 70-80 mph, that is terrible. My 86 (different motor and tranny, I know) gets 24 city and well over 37 freeway (@75-80mph). But even the PA on the 3800 gets 27-28 freeway mpg.
When you get around to that connector, you should be able to find out what is wrong, so until then, good luck fixing it.
I think that the O2 sensor should only be changed once every 200,000 miles, or when it goes bad (telltale black ehuast). The computer is used to seeing the signal from that particular sensor, so can easily adjust to it. Not sure if this is the same on new cars, but it usually takes about 20-30 starts and operating temperature runs for a computer to fully adjust to the reading of a new sensor.
When you get around to that connector, you should be able to find out what is wrong, so until then, good luck fixing it.
I think that the O2 sensor should only be changed once every 200,000 miles, or when it goes bad (telltale black ehuast). The computer is used to seeing the signal from that particular sensor, so can easily adjust to it. Not sure if this is the same on new cars, but it usually takes about 20-30 starts and operating temperature runs for a computer to fully adjust to the reading of a new sensor.
sierrap615
11-06-2004, 12:34 AM
Anyway, for simplicy and everyones understanding, these are the types of connectors I have identified:
1) "OBD-I" using the ALDL/12-pin connector
2) "OBD-I" using the 16-pin SAE J1962 connector (same as the OBD-II connector)
3) OBD-II (VPW,PWM,CAN,&ISO) using the J1962/16-pin connector
4) Unknown (probably early OBD-II experiment) using the J1962/16-pin connector
add mine on there also
5) OBD-II (or early OBD-II experiment) using OBD-I 12-pin connectior.
i used the standard GM OBD-I hook-up connector and it worked fine for OBD-II, i still don't know why i got 3 digit codes.
1) "OBD-I" using the ALDL/12-pin connector
2) "OBD-I" using the 16-pin SAE J1962 connector (same as the OBD-II connector)
3) OBD-II (VPW,PWM,CAN,&ISO) using the J1962/16-pin connector
4) Unknown (probably early OBD-II experiment) using the J1962/16-pin connector
add mine on there also
5) OBD-II (or early OBD-II experiment) using OBD-I 12-pin connectior.
i used the standard GM OBD-I hook-up connector and it worked fine for OBD-II, i still don't know why i got 3 digit codes.
avatar307
11-06-2004, 12:25 PM
That's right! Sorry, I forgot to mention your 1995 Regal (it is a Regal right?) with the really messed up connector. (I think that's even a little more messed up than mine.) Again, completely undocumented anywhere.
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