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I just changed the spark plugs, I didn't had much time so I only swapped the SP from cylinder 3 to cylinder 1. Hereīs how they looked.
The mehcanic didn't change the spark plugs, I know this because I bought platinum SP, and those are Iridium. I know I should buy iridium next time and change them myself. The car has 88k miles, is 16 years old. I know that 88k miles isn't when they are supposed to be changed but where I live I do a lot of city driving, a lot of bumper to bumper traffic (I live in Panama the country), that car I would guess that the equivalent to a car living in America has to be the mileage converted to kilometers, I'd say that the equivalent has to be around 140k miles. Litteraly where I'm from, if the traffic is too bad, just to move 2 miles it takes like 15 minutes.
I'm not that good at reading spark plugs, how do you think they look? Should I replace them? I didnīt see any cracks on them. Cylinder 1 Cylinder 1 Cylinder 1 Cylinder 1 Cylinder 3 (misfiring) Cylinder 3 (misfiring)
Cylinder 3 looks quite sooty (rich or oily. Certainly suspect)
Cylinder 1 looks fine but worn
Was there oil in the #3 plug well? Like on the coil pack rubbers? (Common at this age with these engines. Mine did until I changed the rocker cover gaskets)
Personally I'd be putting in a set of 8 new plugs and be done with it (16 years and 88k miles it is time enough), but for now can you put 1 in 2, 2 in 1. 3 in 4, 4 in 3, etc, etc to see if the missfires moves cylinder.
I just spent a bit of time rereading the first post and translating the codes into words. Ignore my previous comments as I missed a couple of clues.
The codes in words from google (my comments)
P0031 - o2s1 heater circuit low voltage (odd where is that voktage going)
P0172 - rich bank 1 (computer thinks there is too much fuel)
P0175 - rich bank 2 (computer thinks its rich)
P0300, - random missfires
P0301 - miss cylinder number 1
P0303 - miss number 3
P0305 - miss number 5
P0307 - miss number 7
So the computer will be trying to pull as much fuel as possible from bank 1 to bring it back to its ideal air fuel mix - until it hit maximum threshold it can as programmed and throws a check engine.
However both banks are running negative 20 ltft
"The car was disconnected from the battery for around 3 or 4 days, then, I connected it back again, the car ran fantastic, had plenty of power"
Computer reset back to base tune - effectively ignoring the o2 sensors as it calibrates itself. My car runs super smooth for first 30 minutes after a reset. Some of the codes/symptoms take longer than others to trigger/return. Also means plugs and coils are ok.
sounds like it is leaning itself out to point of misfiring on basis of a false rich reading. Although there is a bank 2 code there
I notice the o2s1 on bank 1 reads 1.27v! Yet the sensor 2 is at 0.03v which is very lean. Impossible for a catalytic converter to remove that much fuel.....
I've never seen a functioning o2 sensor read more than 0.95v. Sounds very much like a faulty o2 sensor as I'm pretty sure they are designed not to go above 1v. Ever. Regardless of how much fuel really is there. That, or somehow extra voltage is getting into the circuit on the way to the computer somehow through damaged/altered wiring.
"Also, that O2 sensor my dad has changed it 2 times already, that code has always been there but the car wasnīt misfiring that bad, I only remember it misfiring this bad a few years ago but I donīt remember if it fixed itself or something changed, weīve had this car since 2012, so yes, that code has been there for 8 years straight (world record maybe?)."
Which code has been there for 8 years?
Which o2 sensor was put in? Denso? Or another brand?
Was the wiring touched? Checked?
if a code keeps coming back, it is likely something is wrong that is potentially contaminating the o2 sensor or there is a wiring problem between o2 and computer.
At this stage, before putting in a new O2, is there any chance of graph/charting the following sensor readings after computer reset (would be better to see sensor readings on base tune when everything is running smoothly)?
all 4 o2 sensors
the maf
Throttle position sensor
rpm
Speed
engine temp
Ltft b1
Ltft b2
About 15-30 minute drive should be enough to see sensor readings and computer behaviour as engine goes from cold to hot and computer start tuning itself from base.
Would be good to see the wave forms in separate charts.
Alternatively post the data file from techstream here and I'll take a look.
The P0031 code has always been there, all the O2 sensors were replaced with Denso sensors (all 4 of them, also the B1S1 sensor was replaced 2 times just in case). I believe the wiring has never been checked, we have always suspected that is the problem, I have a multimeter so I'll check them and also the O2 sensor for resistance. Iīll do the reset on the computer again and then run the tests, the nut that connects the negative terminal was stripped the last time (not sure why, I never overtorque anything, I'd say I undertorque everything) so I'll get a new one next week since the government is putting the country on lockdown and we can't leave our houses until January 5th and then we can only leave the house for 2 hours until January 15th. Would you like me to run these tests right now? The car hasn't thrown any misfire codes yet, but the P0031 appeared again, it misfires sometimes but I think its running as good as it always has, I don't know if you would like me to do the tests now and when I get the nut for the terminal disconnect it and run the test again when the car is on it's factory settings and do a side by side.
Since the last time the battery was disconnected the car has driven around 70 miles and it has been running for at least more than 5 hours I'd say.
Plugs look rich. You seriously need to just go over ALL the vacuum lines and put them exactly where they need to be and replace or clean the MAF sensor and make sure there are no leaks anywhere on the intake tract and finally replace the O2 sensors with factory ones
Check your injectors to make sure they are not sticking open
Can I do a smoke test on the intake? Like with a cigar or something like that? Or that won't be enough? The MAF has been cleaned not too long ago, maybe like a month ago.
Cylinder 3 looks quite sooty (rich or oily. Certainly suspect)
Cylinder 1 looks fine but worn
Was there oil in the #3 plug well? Like on the coil pack rubbers? (Common at this age with these engines. Mine did until I changed the rocker cover gaskets)
Personally I'd be putting in a set of 8 new plugs and be done with it (16 years and 88k miles it is time enough), but for now can you put 1 in 2, 2 in 1. 3 in 4, 4 in 3, etc, etc to see if the missfires moves cylinder.
There was only oil on one coil, but it was on the other bank, I think cylinder 4, but no, on cylinder 3 there was no oil on the coil. Iīll look for some iridium plugs to replace them.
The P0031 code has always been there, all the O2 sensors were replaced with Denso sensors (all 4 of them, also the B1S1 sensor was replaced 2 times just in case)..
Perfect. Did you keep the first one by chance?
I believe the wiring has never been checked, we have always suspected that is the problem, I have a multimeter so I'll check them and also the O2 sensor for resistance.
I think this could well be it. If the circuit is damaged no amount of sensor swapping will fix it.
I'd be checking for shorting between the heater and sensor reading circuits
As well as each circuit from connector at the sensor connecyor back to the computer in case there is some other misdemeanour going on.
Originally Posted by OliverLS
Iīll do the reset on the computer again and then run the tests, the nut that connects the negative terminal was stripped the last time (not sure why, I never overtorque anything, I'd say I undertorque everything) so I'll get a new one next week since the government is putting the country on lockdown and we can't leave our houses until January 5th and then we can only leave the house for 2 hours until January 15th. Would you like me to run these tests right now?
I've done that before. Battery connectors do seem to wear out overtime. Seem to be made from v.soft metal.
No hurry if there is a lock down, there is a lock down. Plenty of time to reset the computer! Can you check the b1s1 o2 sensor wiring during lockdown? Is that an allowed activity?
Originally Posted by OliverLS
The car hasn't thrown any misfire codes yet, but the P0031 appeared again, it misfires sometimes but I think its running as good as it always has, I don't know if you would like me to do the tests now and when I get the nut for the terminal disconnect it and run the test again when the car is on it's factory settings and do a side by side.
I don't really need side by side. If the wiring has a problem and you fix it in the meantime the code won't come back = yay!
I just want to see the key engine sensor behaviour data on base tune (ie straight after the computer reset) to see how they are responding before the computer starts making compensations.
Ie air flow reading vs throttle position, speed & rpm.
o2 signal behaviour
Originally Posted by OliverLS
Since the last time the battery was disconnected the car has driven around 70 miles and it has been running for at least more than 5 hours I'd say.
That's heaps. The computer will already be compensating for things according to the sensors (true or false) readings in about 10-20 miles and continue to refine its tune based on recent accumulated data.
Similarly, when I've changed a faulty part without resetting the computer it takes a trip or two for the code to go away by itself without reset as the new data gradually supersedes the older data.
I think this could well be it. If the circuit is damaged no amount of sensor swapping will fix it.
I'd be checking for shorting between the heater and sensor reading circuits
As well as each circuit from connector at the sensor connecyor back to the computer in case there is some other misdemeanour going on.
I've done that before. Battery connectors do seem to wear out overtime. Seem to be made from v.soft metal.
No hurry if there is a lock down, there is a lock down. Plenty of time to reset the computer! Can you check the b1s1 o2 sensor wiring during lockdown? Is that an allowed activity?
I don't really need side by side. If the wiring has a problem and you fix it in the meantime the code won't come back = yay!
I just want to see the key engine sensor behaviour data on base tune (ie straight after the computer reset) to see how they are responding before the computer starts making compensations.
Ie air flow reading vs throttle position, speed & rpm.
o2 signal behaviour
That's heaps. The computer will already be compensating for things according to the sensors (true or false) readings in about 10-20 miles and continue to refine its tune based on recent accumulated data.
Similarly, when I've changed a faulty part without resetting the computer it takes a trip or two for the code to go away by itself without reset as the new data gradually supersedes the older data.
Great!
I didn't keep the first o2 sensor. And yes, I can check the o2 sensor wiring in my garage so I'll be doing that probably tomorrow.
Yes. Should be enough to find leaks, although there are some youtubes on using a soldering iron, a jar and castor oil for a higher volume of smoke.
T
may be an silly question, but when was the air filter replaced with a new one?
Great, I'll do that smoke test, and yes the air filter was replaced with a new one last year, I replaced it myself so I know itīs new, I bought an AC Delco but for some reason the packaging said AC Delco but the filter itself had Denso written on it.
Can I do a smoke test on the intake? Like with a cigar or something like that? Or that won't be enough? The MAF has been cleaned not too long ago, maybe like a month ago.
Hi everyone, this is an update on the car, today I tried to check the wiring on the o2 sensor, it was very difficult, I donīt think I even discovered anything useful since I got really bad nausea from being under the car and some heavy headaches from it, so I stopped doing it, it's not the first time this has happened to me, and itīs not something I worry about but it's annoying because it limits my abilities to do stuff like this, this is what i found, and also I have another question which I will write with the image that I'll upload. Is it safe to place the jackstands on this part of the car? The notch where I am supposed to jack the car is heavily damaged so I place it here but I would like to know everyoneīs opinion on this The o2 sensor plug with some sort of wiring connected to it. In this image itīs more detailed, from what I can see is the wiring coming from the o2 sensor plug takes a curve down and it connects to a plug which you can see on the next image, This is the wiring from the plug which I believe is conected to the o2 sensor plug, I know there are supposed to be 4 wires on the o2 sensor, here I see 2, so it could be either the 2 cables for the heater or the other 2 wires, but I am not sure, this is just speculation, for all I know this could be a plug for the speakers (jk). Here is another picture of the plug, it looks like its covered in oil.
I am really sorry for not being able to post better images, I didnīt imagined it would be so difficult looking at the wiring under there, plus the calustrphobia. If this plug covered in oil doesnīt correspond to the o2 sensor let me know and I'll go ahead and take a better look under the car. Thank you for reading!
I'll try and get the nut for the battery so I can go ahead and disconnect the battery and do the reset, I'm taking alot of time because here in Panama the government has heavy restricctions, I know this isnīt car related but if you think I'm taking too long to respond it's because of these ridiculous restirctions, for example, women can leave the house for 2 hours (this is monitored by the last number of your ID, the police are on the street pulling everyone over and checking their ID number) on monday, wednesday and friday, men can leave the house tuesday and thursday, saturday and sunday nobody can leave their house.
From what I can tell from the pic about the jack stand spot it look similar to where I put them on my car. Is that the chassis rail? In which case you should be fine, I tend to be double paranoid about cars falling down when underneath so I typically leave a secondary just-in-case jack or block or an old spare wheel somewhere. Just incase something unpredictable or uncalculated goes wrong there is time to get out from under. As yet haven't needed it but that is why it is just in case.
It's a pain being down there - lifts make it so much easier. When I changed my sensors a couple of years back - bank 2 took me about 20 minutes and was really straight forward. Bank 1 on the other hand took me well over an hour because the B1 plug is hidden behind that stupid head shield I can't recall if it was possible to remove the shield but at the time I think it would have required a lot of f'ing about. As I was just changing the sensors I just used a pry bar to open out the heat shield enough (10-20 mm or whatever) to get to that plug, but not too far that the shield would hit anything else.
Strange thing is on bank 2 the sensor isn't behind a heat shield and is really easy to get to. I couldn't see any particularly obvious reason for why they are different - It's like they had 2 different design teams on each side of the engine....anyhoo I'd recommend prying the shield out a bit to get access to that plug.
Given it is bank 1 sensor 1 is difficult to to access the plug, it does make me wonder if the mechanic who didn't install your spark plugs also didn't change that sensor. It's hard to tell from the photos, but it doesn't look newish. If you do decide to swap the sensor with a new one, make sure it is a Denso one. There is no point gambling with non-genuine o2's or MAF sensors given how critical they are to making a car run right.
The other 2 wire sensor is the oil level sensor - completely unrelated. you can ignore it at the moment.
Yes govt restrictions are a pain. Don't stress if it takes a while. The sooner covid is gone the better for everyone. If everyone stays home and wears mask in public if they have to go out for supplies, the virus does stop spreading.
Take our country for example, we had gotten rid of the damn virus and had enjoyed about 2 months of being back to normal with no local transmitted cases. But now we are back to having the stupid covid restrictions because our government quarantine procedures are inadequate. They let 2 cases back into our country from overseas 3 weeks ago and now those 2 cases have turned into 250 cases because people have cars and like to go places... Had the government not let those cases out of quarantine, we wouldn't have restrictions now. That said it is here, so if everyone follows the restrictions and stops trying to be a hero (defiant, deniers or whatever you call it) it will be gone again in a few weeks. Basically what I am trying to say is I could complain but instead I am just staying home unless absolutely having to go out. And when I do go out it is with a mask, handwashing etc. The upside of the situation is more time to contribute on the forum and catch up on other things which I normally don't get time for. Sounds like the perfect time to get on top of getting your Lexus running right.
From what I can tell from the pic about the jack stand spot it look similar to where I put them on my car. Is that the chassis rail? In which case you should be fine, I tend to be double paranoid about cars falling down when underneath so I typically leave a secondary just-in-case jack or block or an old spare wheel somewhere. Just incase something unpredictable or uncalculated goes wrong there is time to get out from under. As yet haven't needed it but that is why it is just in case.
It's a pain being down there - lifts make it so much easier. When I changed my sensors a couple of years back - bank 2 took me about 20 minutes and was really straight forward. Bank 1 on the other hand took me well over an hour because the B1 plug is hidden behind that stupid head shield I can't recall if it was possible to remove the shield but at the time I think it would have required a lot of f'ing about. As I was just changing the sensors I just used a pry bar to open out the heat shield enough (10-20 mm or whatever) to get to that plug, but not too far that the shield would hit anything else.
Strange thing is on bank 2 the sensor isn't behind a heat shield and is really easy to get to. I couldn't see any particularly obvious reason for why they are different - It's like they had 2 different design teams on each side of the engine....anyhoo I'd recommend prying the shield out a bit to get access to that plug.
Given it is bank 1 sensor 1 is difficult to to access the plug, it does make me wonder if the mechanic who didn't install your spark plugs also didn't change that sensor. It's hard to tell from the photos, but it doesn't look newish. If you do decide to swap the sensor with a new one, make sure it is a Denso one. There is no point gambling with non-genuine o2's or MAF sensors given how critical they are to making a car run right.
The other 2 wire sensor is the oil level sensor - completely unrelated. you can ignore it at the moment.
Yes govt restrictions are a pain. Don't stress if it takes a while. The sooner covid is gone the better for everyone. If everyone stays home and wears mask in public if they have to go out for supplies, the virus does stop spreading.
Take our country for example, we had gotten rid of the damn virus and had enjoyed about 2 months of being back to normal with no local transmitted cases. But now we are back to having the stupid covid restrictions because our government quarantine procedures are inadequate. They let 2 cases back into our country from overseas 3 weeks ago and now those 2 cases have turned into 250 cases because people have cars and like to go places... Had the government not let those cases out of quarantine, we wouldn't have restrictions now. That said it is here, so if everyone follows the restrictions and stops trying to be a hero (defiant, deniers or whatever you call it) it will be gone again in a few weeks. Basically what I am trying to say is I could complain but instead I am just staying home unless absolutely having to go out. And when I do go out it is with a mask, handwashing etc. The upside of the situation is more time to contribute on the forum and catch up on other things which I normally don't get time for. Sounds like the perfect time to get on top of getting your Lexus running right.
Let us know how you go with that plug.
Oh yeah they are very hard, as of right now, Panama is the number one country in the world in COVID 19 cases per 1 million people. But yeah, looking at the bright side I can check out the problems in the car and try to fix them, today I didn't go under the car but I pulled some codes, for some reason my techstream is acting up so it was very difficult, the computer doesn't even want to look at live data, I'll check it again later, but there were new codes (I'm actually happy for this because it gives me a better idea of what is the problem with the car).
A few days ago when I checked the Engine Coolant Temperature sensor a pulled it out (of course I broke the clip but I it connected again but with no "click" sound) I connected the multimeter to the sensor and got the ohms reading which was around 1770 at 20K ohms, and I measured the voltage on the plug which was I believe around 5V or maybe less, I can check again. I tried to start the car (with the sensor disconnected) and it didn't start, tried again and it started but stalled, so I connected the clip again and it did start.
The codes I pulled were P0031 (again of course), P0118 (new) and P0133 (new).
The P0118 could be because I tried starting the car with the sensor disconnected or something like that? These cars trip codes so easily. The car does take a bit of time to warm up, a day ago I was idling it for about 30 minutes and it didnīt warm up, and the car starts up with the fans running (not at full blast), it eventually gets up to the right temperature.
Oh yeah they are very hard, as of right now, Panama is the number one country in the world in COVID 19 cases per 1 million people. But yeah, looking at the bright side I can check out the problems in the car and try to fix them, today I didn't go under the car but I pulled some codes, for some reason my techstream is acting up so it was very difficult, the computer doesn't even want to look at live data, I'll check it again later, but there were new codes (I'm actually happy for this because it gives me a better idea of what is the problem with the car).
A few days ago when I checked the Engine Coolant Temperature sensor a pulled it out (of course I broke the clip but I it connected again but with no "click" sound) I connected the multimeter to the sensor and got the ohms reading which was around 1770 at 20K ohms, and I measured the voltage on the plug which was I believe around 5V or maybe less, I can check again. I tried to start the car (with the sensor disconnected) and it didn't start, tried again and it started but stalled, so I connected the clip again and it did start.
The codes I pulled were P0031 (again of course), P0118 (new) and P0133 (new).
The P0118 could be because I tried starting the car with the sensor disconnected or something like that? These cars trip codes so easily. The car does take a bit of time to warm up, a day ago I was idling it for about 30 minutes and it didnīt warm up, and the car starts up with the fans running (not at full blast), it eventually gets up to the right temperature.
Responding to myself, I believe I found some interesting information, I was able to look at live data and found this. Also, I erased the codes and very quickly the car started misfiring very badly again, it didnīt give me the P0031 code yet, but it gave me the P0303(5-7) code again, and i even swapped the Spark plugs of cylinder 3 to 1 so it makes me think that the problem isn't the spark plugs (but probably should replace them). I revved it to about 2500 rpm and the car just stopped misfiring that badly, then it went to idle and started misfiring again, I revved it again to 2500rpm and it started idling pretty nice again.
Also, i checked with a thermometer the coolant temperature in the radiator and it was about 46 degrees celcius, the techstream gave me the same number so I think the temperature sensor might be ok. Car off Car off, check out that O2 B1S1 voltage! The car is running rich even when its off, amazing! lol Car idling Car idling Car idling Car running at 2500 rpm Car running at 2500 rpm Car running at 2500 rpm
12-31-20, 01:23 PM
and catch up on other things which I normally don't get time for. Sounds like the perfect time to get on top of getting your Lexus running right.
