Car dies out

Alright I have had help before in the past with other issues dealing with heat and over heating. But now I have another problem hopefully someone can help me. I have a 2000 Lincoln LS V6 3.0 with 215,800 miles yea thats high but its drover daily everyday. But never had any problems out of it besides regular maintaining vehicles tune up. But the over heating which was my fault. And the heat itself, which SHOROD helped me figure that problem out THANKS TO YOU SHOROD. Well my issue is my car will turn over fine and start fine with no problems at all. Car idles fine with no problems. Sitting still you can rev it up and no hesitation it does. Well I can drive from here to the interstate which is 3 miles as soon as I get onto the on ramp and press the gas to speed up (so i dont get ran over) it stalls (dies) out on me a little bit its like the harder I press the gas the faster it does out. But I can pull to the shoulder of the road and turn the car off and let sit then start it back up and drive off its fine then in between that 3-5 marker it does the same thing all over again. At a steady speed its fine but when you are trying to speed up it dies (slows). Someone please help

What elements do you need for a good burning Fire?
Air, fuel, and ignition.

Troubleshoot Random misfiring-
A stickey throttle plate, Air filter, fuel filter, fuel pumps, fuel regulator, also a plugged Catalytic converter will choke a motor out.

I have good fuel pressure, air filter is good, fuel filter is good, fuel pump is good,ignition is good. Everything happens as it should until that 3-5 miles marker you hit the gas again and it dies down. I dont know what it could be I was leaning towards a mass air flow sensor. Be honest though I dont know much about a lincoln ls. But everything does as it should util 3-5 mile marker, I can cut the car off start it back and take off and it runs as it should until the 3-5 mile marker again. Its like the computer resets whatever is wrong with it when I cut it off.

Also my Cat con. are gutted so dont think they are stopped up.

Try cleaning the MAF, IACT, and throttle body!If cleaning the MAF/IACT dosn't work, I would consider new.What about the upstream H02 sensors for the Air/fuel mix?

Everything of that nature is fine and running smooth. That would cause it to idle funny wouldnt it? But I tried cleaning the MAF last night and still nothing the same thing is happening Im gonna see if the EGR needs cleaning also maybe that will make a difference

The EGR should only have an effect at idle speed, not when you are accelerating.

If you gradually lean in to the throttle do you notice anything abnormal such as a hesitation or stumble? How long do you have to leave the car sit before restarting? Have you checked for pending diagnostic codes? Do you have a scan tool with a datastream mode? It would be interesting to monitor the short term fuel trims and the engine coolant temperature sensor just prior to the stall.

-Rod

The EGR should only have an effect at idle speed, not when you are accelerating.

If you gradually lean in to the throttle do you notice anything abnormal such as a hesitation or stumble? How long do you have to leave the car sit before restarting? Have you checked for pending diagnostic codes? Do you have a scan tool with a datastream mode? It would be interesting to monitor the short term fuel trims and the engine coolant temperature sensor just prior to the stall.


Well if I gradually lean to the throttle it still kind of dies out a little but not as bad as it would if you give it more gas. I can turn the car off and start it back up and its fine for that 3-5 miles range. Havent checked for codes. The check engine light isnt on so no codes will show up on the scan tool. For some reason.

There could still be pending codes, even though the Check Engine Light is not on.

Sounds like you have a misfire or vacuum leak. I'm not sure why it would always take a few miles to show up, I'll have to ponder that a bit....

-Rod

I have no clue on it I have looked searched every part of the net no one can seem to find the answer. Wouldnt a misfire cause the car to stutter or sputter skip hop that type of thing? I would think. What about a vacuum leak that would maybe start as soon as the car is started up.? As I would think again but that assume why I dont have a mechanic job right... My guess is still floating around the mass air flow sensor. Thats just my guess. I will go by a friend of mine and see if he can put it on that scan tool to see if any codes come through. I know my cat converts will show up cause they are gutted. Other than that I dont know but I will check early in the morning as soon as he wakes up and puts it on test I will reply back with codes thanks Rod

Well if I gradually lean to the throttle it still kind of dies out a little but not as bad as it would if you give it more gas.

This descriptions sounds a bit like a misfire/vacuum leak. It's difficult to interpret a verbal description of "dies out a little" as different from a misfire stumble.

The odd part is the constant reset since any of the sensors (MAF, O2, TPS, or ECT) since the PCM will evetually be in closed loop due to engine coolant temperature.

I suppose an electric motor could "reset" like what you describe. Typically fuel pumps will fail to supply enough pressure for start up, but will be fine once the vehicle is running. But my basis of symptoms are more from fuel systems with a return line. Your LS has a returnless fuel system so the power to the fuel pump is modulated to attempt to maintain fuel pressure.

I think you really need to have a scan tool in the datastream mode monitoring the sensors while the problem occurs to get you pointed in the right direction.

-Rod

Ok new condition. Today went to my buddy's house and put it on the scan computer well the scan picked up cat con. which I figured it would considering that they are gutted. Well I left the car running at the point and time then the car just acted like it wanted to cut off completely like it was loosing fuel pressure. So I go buy a fuel filter. Same thing. So now I went and bought a fuel pump. And in the process of about to change it if I can figure out how to get to it.

Well before I replace the fuel pump. I took the back seat out and turned the key on you can hear the fuel pump running with no problem at all. doesnt sound like it even dies out. You can start the car runs fine then at around 3500-4000 rpms the car stalls down and/or misfires sounds like it pops from the muffler. I was reading through other sites and same thing is happened to the same year lincoln ls v6. Said he took it to a mechanic and the mechanic knew exactly what it was he changed the jet pump and it was fine puuurrrs like a kitten he says. Wonder about that situation. As in all the scan picked up no codes but only the cats which I knew it was going to do that. (Gutted) Which they have been gutted before this ever happened. So now Im on the guessing level that its either air or fuel related.

Alright I just changed the fuel pump. And nothing but right before I changed it out, at idle the car skip and sputter. Well now that I changed the fuel pump. I got no different results now it will start up and run for a second or two then it will start sputtering and skipping and then it cuts off. You can hold the gas to the floor and it still does nothing it loses power faster. Now Im really stumped cause everything on the car is basically new and Im lost for words. What is my other options. I have checked all hoses and found no leaks. There is no vacuum leaks none that I can find. Can you help me figure this situation out as soon as possible. Cause thats my only transportation and I have no other ride back and forth to work.

In park or neutral the car is designed not to let you over-rev the engine. You're bouncing off that rev limiter at 3500 or so rpms, there's no "jet pump" causing that, it's completely normal and by design.

I hate to say it, but you're probably at a point where you need to visit another shop or the dealer. With all you've replaced you might be at the point where you've exceeded the diagnostic and repair costs a knowledgeable dealer would have charged, plus you'd likely have a running car by now. It's either that or find a scan tool with the datastream mode that you can have logging when the car acts up. You need to determine if fuel or spark is acting up, anything else is shotgunning and potentially wasted money. For the cost of the fuel pump you probably could have purchased such a scan tool.

Or in advance of that, the next thing you could confirm is that you have good compression on all 6 cylinders. But again, that wouldn't make sense to "reset" immediately after a stall.

-Rod

You can start the car up and it 15-30 seconds it stalls and cuts off now it seems like problem is getting worse and worse. Just 30 minutes ago I started the car and try seeing if I could even get it to go down our 1/2 mile dirt road. Well needless to say i didnt make it down the dirt road I kept having to turn the car off then start it back I did this 3 times down and 5 times back cause you cant turn around on the dirt road it has a ditch on either side. Well at idle it idles rough then cuts off. I have changed the fuel pump, fuel filter, and jet pump. MAF I have cleaned with MAF cleaner. I have took the throttle body off and its components that are attached cleaned them with intake cleaner. Cleaned all of the electronic plug ins with electronic cleaner. I havent changed the fuel regulator, MAF sensor, or ignition coils. To be honest I dont think that the ignition coils have ever been changed. I have been looking around on the net for other information, and gathering from AF forums (past forums) and I have seen people end up with jet pumps, fuel filter, fuel pumps, fuel regulators, MAF sensor, and ignition coils. I have changed everything but the last three. The car has been good over the years it has lasted me 216k miles that wonderful to me. But I would love to have it as long as I can.
The dealer/mechanic does not know whats wrong with it. They said that is an unusual situation for the car to be acting like that considering that I have had all of the above changed out. I have a friend that works on Jaguars considering that the Lincoln LS is basically a Jaguar he is coming over to see if he can determine what the cause of shaking, stumbling, stalling, and whatever else could possibly going wrong with it. If you have any more ideas or information for please help, cause Im stumped. Thanks Shorod

Where can I buy the scan tool with the datastream mode at? Can I buy it at a local auto parts store?

Where can I buy the scan tool with the datastream mode at? Can I buy it at a local auto parts store?

Here's the one that I have.

http://www.autoenginuity.com/

Hey Joegr,
how much did you pay for your scan tool. I've been thinking about buying one as well.
JP

Autozone sells a higher end Actron that does datastream. You could also go with the AutoXray EZ-Scan and TechScan products, CarChip, and Harbor Freight even sells a scan tool with datastream capabilities.

-Rod

Found something dont know how much of a problem it would be but thought I would share the information with you. Ok last night I was looking around on the forum and found a thread talking about PCV well all the threads were showing collapse and dime holes so I decided to find that and see if that was a problem and no it wasnt as taking the manifold off and the fuel rail and took the ignition coils out. Then the spark plugs every one on the right side (standing in front of the car looking at the motor) looks good a little smutty but good. Now for the left side everyone looked good until I got to the last one one closest to the firewall I pulled the plug and looked there was oil around the prong (spark) none on the ignition coil. But when I looked at the plug seems like the oil was just built up around the thread of the plug not around the end. Is or could this be my problem. Now Im on the verge of using it as target practice. Cause I have read up on more threads about the same thing and you (rod) were telling some one if it was around the coil it would be valve cover gasket if it was around the spark it was possibly a damaged ring (cylinder wall) Hopefully this problem cause be resolved without snatching the motor out swapping it out rebuilding the motor..

It's probably on the threads due to the oil running down as you are unscrewing it. A single cylinder misfire would not likely cause stalling, and the misfire monitors on these OBD-II cars are pretty good. If that were the problem I would expect you to have a Cylinder #3 misfire code (P0303). The cylinder nearest the firewall on the passenger side would be cylinder #3. Does the electrode of the plug suggest that it's not been firing? Also, the plug and head will hold quite a bit of heat. If it takes 3-5 miles for the plug to heat up enough to act up, it won't cool in just a few seconds and go another 3-5 miles.

-Rod

I figured that it was oil from me unscrewing the spark plug it just seems like its around the threads not the spark of the plug. Theres no codes of showing misfires at all. Only codes that show up are o2 sensors lean bank 1 I think thats what I recall as far as the rest of the code I dont know. But I do remember that he said bank 1 lean. Well its not 3-5 miles now its as soon as you start the car it will run like a kitten for 10 seconds then shake, stumble and off it goes. Then you can start it right back up but this time it doesnt take 10-15 seconds it takes 3-5 seconds now then it idles rough shakes and off it goes again. I have took the intake manifold off cleaned it out. throttle body cleaned it. checked the vacuum lines and none seem to be hurt (cracked broken or even collapsed together).... I thought of letting a rag sit inside that #3 and soak up what oil is in there and then get new plugs trying that and seeing if that will help any. I have ordered new ignition coils but doesnt seem to be the problem because they look good and have no oil around the penciled boot. That was a doubt for me, cause of there being no oil around the boot showing no signs of leaking oil down to the spark plugs. Also is there anyway that you can send me pictures of this PCV you were talking about on another thread please.

My email address is bagged02xtreme@yahoo.com
I was looking at another motor today for sale has 60k miles on it for $1000 which me personally think thats a good deal. But hopefully I wont need to buy another one if I can get this one resolved.

Hey Joegr,
how much did you pay for your scan tool. I've been thinking about buying one as well.
JP

I think it was around $400.

Also is there anyway that you can send me pictures of this PCV you were talking about on another thread please.

The info should be in your Yahoo inbox.

-Rod

Thanks rod.
As soon as I get the ignition coils and the spark plugs changed out I will update this thread to keep you informed. Also Im going to check on that valve to see if it is harmed in any way. If so I will just have it changed too. Thanks again
If anyone has any other suggestions please give me some info thanks

***UPDATE***
Nothing new. I changed the ignition coils and the spark plugs run for a little bit and the motor would shake a cut off. But I can start the car back up and it will idle fine with no stalls no shaking no nothing. Its just when you smash the gas it will stall, shake and cut off. So I went to local parts store and bought a MAF sensor. By the time I replace everything on the car everything will be new. Going today to pick it up to see if that changes anything. Also I was telling the thread that my cats are gutted. But there is a code that is coming i up which is directing it to cats. Saying bank 1 lean. Can anybody tell me if that would be one of my problems? Or if that would have anything dealing with the car stalling (cutting off) like it does... Thanks in advance

Back to the clogged exhaust. I know the cat con is just a pass thru but if the guts of the muffler have colapsed/clogged you will get a similar symptom. Try pulling out the o2 sensor in front of the Cat Con and run it. It will throw a code but it will emliminate any development of backpressure. Had this happen on a 4.3L V6. Took 2 days to figure it out. When I removed the o2 sensor the exhaust was unplugged and the engine could breath. Worth a shot before you take it to a shop at $90/hour and up.

Alright changed the ignition coils, spark plugs, MAF sensor. Still the same thing changed the MAF sensor hour ago and still got nothing still the same results.

A code for Bank 1 Lean is not pointing to the converters, that's pointing to a condition where there is too much air for the amount of fuel. You either have a vacuum leak letting air in or you have a fuel issue not allowing enough fuel. You could also try removing the O2 sensor as CJ0717 mentioned just as confirmation that the problem is not restricted exhaust.

-Rod

Alright I will try that which is bank 1? I know there is 4 02 sensors on the dual headers. which makes 2 upstreams 2 down streams. If its bank 1 I would figure it would be the drivers side sensors. If I take the 02 sensor out and everything works fine then that would be my problem?

So far you have a decent tuneup completed. Still sounds like something clogging in the exhaust

I just went outside and started the car not to long before you posted and both sides of the exhaust is fine. They are both thumping. Well which I had Borla exhaust on it. I have took a video of it and I could send it possibly to you to show that the exhaust doesnt seem to be clogged in any way at all. Its pretty chilly outside so you can see the steam coming from the mufflers. But on the video it sounds like the car is cammed to death. Sounds like a older muscle car with heavy cam. Which its not cammed it is just at rough idle. I dont see anything that it could be other than the 02 sensors or like in the past post broke ring cause I did find oil on the end of the plug (spark) but I figured that was oil that came from around the valve cover, but there was oil on the ignition coil.

I noticed that you were telling me to take the sensor out well which one should I take out. I know it would be on the drivers side but would I take the up stream out or the down stream? Or take both out..
?

Remove any sensor just upstream from the cat converter. The easiest one to get at. Should take a couple minutes but at least it will confirm whether or not the exhaust is restricted. If it runs OK with this out then the muffler must be clogged up or something since you've said the cat converter is just a hollow tube now.

Alright heres another ***UPDATE***
So I took you advise Mr. CJ and Mr. Rod I go outside yes its cold and I took the driver side upstream 02 sensor out and guess what happens yes you should have guessed it it runs like it suppose to... I hit the gas to it at a stand still the RPM jumps up without any hesitation. It doesnt stall it doesnt do anything weird anymore. Alright now heres the question what now could be the problem bad 02 sensors or stopped up muffler or Cat? Has to be one of the 3 right? Well Cats are gutted as so as I thought. The exhaust system (borla) has been on there for a little while but I have a back up set of mufflers that I was going to put on my xtreme. Is there anyway that I can save my exhaust system without junking it? If push comes to shove I will swap the system out of it. So what do I do now is the question? :) thanks for your help I really do appreciate it without a doubt. Saves a ton of money when you have internet and a automotive forum that will help you save them big bucks especially on these cars. Please help again. Im so close to getting this thing back on the road its draining my pockets already.

GREAT!!!:p
This had me stumped for about a week as it progressivly worse. Finally had to take it to a mechanic that I trust alot. Had him stumped for about 8 hours. He told me he slept on it and had a wild idea in the middle of the night. Went in early in the morning and pulled an o2 sensor and viola ran great. Turns out the CAT was clogged. He replaced it and it ran like new. I got stuck with an $800 bill. 200 for the cat replacement and another $600 in diagnosis time. That stunk but it was fixed and running again.
I am very glad that I was able to save you the diagnosis time. This type of problem is very hard to find.
Now for your question. THe O2 sensor is probably fine. Alot of people change these when they get an O2 sensor code only to find out that the O2 sensor was telling them what the needed to know. At $70 a pop the parts dealers love this one.
I would start with the Cat Conv and make sure it is still a pass thru deal and that nothing left internally from the last time collapsed and clogged it. If that is ok then replace the mufflers. When these get old and rotted they can either start collapsing in on themselves or rot thru to the outside. It's when they collapse is when the engine's performance is affected.
LEt me know what you find and how you make out.

Have a great day in the cold :)

CJ:wink:

I shall do so. Went to day and picked up some PB blaster to get the bolts off the flange from the catalytic converters so I can see if thats the problem I thought about taking the half exhaust off and see if thats the problem first if thats it, it should be the mufflers. If it continues I know its the cats right? Im just guessing on the whole thing.

I'd be guessing too. It's 50/50 but my guess is the Cat Conv. probably fellapart internally. You won't know until it comes off. Good thing is you know for sure its an exhaust issue and not anything else.

CJ:smokin:

Alright maybe somebody can give me some helpful tips on the same subject. Alright in the process of trying to check if the cats were stopped up. Well while doing that I had to take the down pipe off of the headers cause the cats are right at the headers has 2 bolts for each side 2 for the left 2 for the right. Well needless to say I only succeeded on getting to nuts off out of the 4 the 2 on the drivers side came off little hard but came off. Passenger side werent to lucky I guess they havent been lubed in forever they had probably seized. Well the 2 on the passenger side snapped. I have tried puttin a pilot hole in it I went and bought a extractor kit with the bits and extractor in it and the bits will not drill into the stud. Any ideas? Every time I fix one problem I get another problem right behind it. Anybody have any ideas?

Oh I also found what my problem was well as I stated in a post before the cats were gutted not likely. Well the driver side was gutted but the screen was still inside there well it was bunched up in a ball into the pipe itself so the screen never was taken out. On the passenger side the cat was not gutted it still had the comb inside. Just to put that into the post to let you know what I have found

Sometimes the drill bits that come with the extractor kits are left-hand bits. That way if the stud being drilled looses while drilling it, the drill bit will back it out. You can visually look at the bit to determine which direction it would need to spin to cut, or you can just try reversing your drill and see if it drills better.

-Rod

Drill going right direction. Just not cutting into the stud which is possibly the bit because one broke and one was cutting for a second and then all of a sudden it just wouldnt cut anymore seems like the bit got dull real fast

Have you tried using a propane torch and just heat the heck out of the stud. THen hit it with some WD-40. Repeat again if necessary. I have found that a good bit of heat will loosen up the worst possible situation. Except of course of you stripped the head on the bolt. Then I would get a die grinder in there and cut the son-of-a-pup right off.

does this die out when it gets warmed up? if so i'd say catilic converters. and if it's the cats sometimes they get burnt red that could cause it to burn up your car. so i'd look at cats when you get it back together and see if they get red.

I have tried the propane torch and nothing, tried the extractor kit cant even get the drill bit to drill a starter hole for the extractor. Its nerve wrecking now.. I would drive it to the muffler shop but it sounds like someone dropped a 454 in it with drag pipes. Its annoying loud. So Im out of options I figure I would get a dolly have it taken to the muffler shop and see if they can do anything good with it pretty sure they can... If I had a welder I would weld them back on bump the flanges in the future I plan on getting a full exhaust system anyways. So after I get the down pipe connected back to the headers I will keep you guys posted on if its running fine after the down piupe and cat converter install back to the header.. Thanks for the help in advance.

Also CJ I didnt try the WD-40 what would I do heat the bolt up and just spray the wd-40 on it? Or what kinda process am I looking at in that situation. Thanks

1st post
What elements do you need for a good burning Fire? Air, fuel, and ignition.Troubleshoot Random misfiring, a stickey throttle plate, Air filter, fuel filter, fuel pump, fuel regulator, also a plugged Catalytic converter will choke a motor out.

www.automotiveforums.com/vbulletin/showthread.php?t=972629 (http://www.automotiveforums.com/vbulletin/showthread.php?t=972629)

Drivers side = bank 2?

1st post
Quote:
Originally Posted by danielsatur
What elements do you need for a good burning Fire? Air, fuel, and ignition.Troubleshoot Random misfiring, a stickey throttle plate, Air filter, fuel filter, fuel pump, fuel regulator, also a plugged Catalytic converter will choke a motor out.
www.automotiveforums.com/vbulletin/showthread.php?t=972629


HUH? Already got this situation solved so far as I know of just trying to get the down pipe bolts that broke off out.

Buy a OEM Cat from www.catalyticconverterwarehouse.com (http://www.catalyticconverterwarehouse.com) , and have a local mufflershop weld it in.

What I have done in the past is to heat up a stubburn bolt/stud red hot. That usually breaks the corrosion up a bit. After it cools down a bit I hit it with a lubricant (WD-40) in this case. An do that 2-3 times. I'm not saying that this will do the job for this stubburn bolt but I've been able to break free some pretty stubborn corroded bolts this way.
I'm sure that a muffler shop will use a cutting torch and just cut it off if it's that hard to break free.
Note: These bolts are usually hardened and a normal High Speed Steel drill bit won't do anything. Maybe try a Carbide bit. Hardened bolts are a pup to work on when they're stuck.
If it were me I would do as you suggested and take it to the muffler shop and be done with it.

Welllllllll today took it to the muffler shop said they were going to get it fixed said something about tapping the bolt thats already on there and gonna weld that on heat up the exhaust manifold and see if they can get it off that way hopefully all goes well. HOPEFULLY... He said I can go pick it up tomorrow. Maybe I found my problem on the cat converters being stopped up well the screen being pushed into the pipe. Hopefully this will solve my problem. Keep you updated. Thanks.

Are you going with New OEM cats, aftermarket cats, or no cats @ all?

Alright alright got some good news and some bad news for the Lincoln LS.
Today got it back from the shop. They fixed the bolts that were on the exhaust manifold put new ones in. Had them to put on my new borla mufflers that I bought. All thats good. **BAD NEWS** still doing the same thing. Whats your pointers now pointing to the 02 sensors? Maybe... If I change the bank 1 will that do the job or should I just change all of them? $80 a round at 320 for the 4 didnt know if I could get away with the 2 on bank 1 or just go ahead and change all of them. Might as well. Thanks....... Derrick

Things that I have changed..... Mass Air Flow sensor. Fuel filter. Fuel Pump. Ignition coils. Spark plugs. Air filter. Sprayed the intake manifold with intake cleaner and also the throttle body. Cleaned all electrical plug ins with ECC. Changed the mufflers to the new borla mufflers. Cats are gutted. Checked the PVC in the center of the motor near the back, no problems with it. As far as I felt and seen anyways. Has newly put on injectors roughly 3 months old. Newly fuel rail 3 months old. New top end gaskets.
The only things I can think of I havent changed that I need to is fuel regulator. Cat backs (glass packs) whatever u call em. EGR. Idle control sensor. Just alot of odd and ends

Did the symptoms of engine dying out disappear?

Hard to believe. When you removed the one O2 sensor it ran great. right? So now with the new cats and mufflers it still bogs down? Try removing the same O2 sensor and see if you get the same result as before.
Before buying 300 dollars worth of sensors on a whim there is a way to diagnose an O2 sensor. I believ I read that you can check the voltage on the output of these when the car is running and get like 0.6vdc or something like that. zero output and I would say a bad O2 sensor.
I'll check a couple of places and get back to you. The last time I went and changed O2 sensors just ticked me off due to the fact that a code for low O2 sensor made me change 3 of them out. $240 and the problem was still there. I wish I would have verified the output voltage and I could have saved $240 bucks.

Get back to you on this

CJ

Found part of what I was looking for. Below is from this web page www.engine-light-help.com
I believe every sensor has a 4 wire connection Black being common(ground) and the others I'm not sure yet. The manufacturer like Bosch would have it avail. I'll look some more.
Here is the section on O2 sensors. They have an output voltage between zero and 1vdc If you are getting 0 or 1 and higher then something is wrong. Normally should be operating at about 0.6vdc

First we need to understand how an oxygen sensor works. The oxygen sensor screws into the exhaust and the sensor end protrudes into the pipe so that exhaust gases pass across the sensors internal element. There is a steel shielding with slots that direct exhaust flow across the actual element. As a note, oxygen sensors used to determine engine fuel ratios are always located in front of the catalytic converter. The sensors behind the cats are called monitors and we will discuss these later. Sensors are normally described with the prefix HO2S meaning Heated Oxygen Sensor and followed with bank and position number. For example HO2S11 would be the oxygen sensor on bank 1 and first in line (pre catalytic converter) and HO2S12 would be on bank 1, but second in line (the monitor) An oxygen sensor creates a voltage between 0 and 1 volt by means of a chemical reaction between the sensor element and the oxygen in the exhaust passing across that element. Outside air also passes through the sensor and it is a comparison between the oxygen content in the exhaust and fresh air that actually determines voltage output (information for trivial purposes only and for curious techs). Believe it or not, the fresh air on many sensors actually travels through the wiring insulation! Anyway, a voltage closer to one volt indicates a rich condition and closer to zero indicates lean. The computer uses this valve to constantly adjust fuel trim to maintain a 14.7:1 air fuel ratio. We will be putting up an article on fuel trim soon but this is a huge topic all on its own. Okay so this is where it gets somewhat complicated. Just kidding! It’s all nuts and bolts; and wires, and chemicals and never mind!

3 or 4 wire sensors. Black = Ground / Blue = signal to PCM (should read between 0 and 1 vdc.)
The 3rd wire goes thru the fuel pump circuit and the 4th can be for a heater element in the O2 sensor.

Hope this saves you some dollars.