WOT O2 Question
07-06-2009, 09:23 PM
#41
I agree with Jon and Texas. You need a wideband to troubleshoot A/F ratio tuning. Do not try to use your stock narrowband O2s to tune for WOT. You will blow up your motor!
Narrowbands are only capable of reading slightly above and below 14.7. (thus the term "narrow") So you want you see if your motor is lean, right? Well, a narrowband can't tell the difference between 14.4 and 12.8 so you might think you're A/F ratio is ok, but is isn't. Anybody that argues with this I will personally kick in the *****.
Get access to a wide band or don't mess with the VE table.
Dan
Narrowbands are only capable of reading slightly above and below 14.7. (thus the term "narrow") So you want you see if your motor is lean, right? Well, a narrowband can't tell the difference between 14.4 and 12.8 so you might think you're A/F ratio is ok, but is isn't. Anybody that argues with this I will personally kick in the *****.
Get access to a wide band or don't mess with the VE table.
Dan
Dan, please reread my post, Im not tuning the VE tables
07-06-2009, 09:36 PM
#42
Your right, it is stupid to trouble shoot with a WB. So why the heck do you have HP Tuners? Man that was a shitty statment you made. I am trying to help you. I trouble shoot with mine all the time. I am an industrial mechanic and I use my Ecom (Emissions equipment that messures O2, NOx, No2, Co, etc.) all the time to trouble shoot, and to tune! I must be an idiot for thinking you can use it to trouble shoot and then to tune WOT with, which you have to have to tune WOT. So forgive me for assuming you have HP Tuners so you must be or want to be serious about tuning your car.
I am done trying to help you. Watch out every one else who wants to help here.
I am done trying to help you. Watch out every one else who wants to help here.
The VE, MAF, injector, and spark tables will remain stock. I own HPtuners and a wideband because I previously owned a heads/cam car which I tuned using that equipment. This car is bonestock and will remain that way.
I noticed a performance issue while driving the car, so I used the scanner to see if I could pinpoint the cause. The only reason I even modified the stock tune was because I blocked off the AIR and EGR.
This forum is PCM Diagnostics and Tuning, not "Wideband or Die." Someone please tell me what I gain by spending an afternoon welding a bung into the exhaust, wiring up the wideband, and datalogging AFR on bank 1? It will tell me if its lean or not? That gets me absolutely nowhere because, last I checked, I can't flip a switch and turn off being lean at WOT on bank 1. The wideband gets me no closer to determining the actual cause of the problem than I currently am. If I am wrong, please explain?
07-06-2009, 10:07 PM
#43
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^^^^ you are on the right track. just so you know, .860mv flatline is in my opinion lean but the other side is even worse. i haven't tuned a 1000 cars, but i have logged over 400 passes at the track with efi live and lm1, the narrowbands have always been consistent with my target wb afr, you just can't microtune the afr with a narrow that is all.
07-07-2009, 09:32 AM
#47
Do you infact know if the engine is running lean or rich? A stock tune is usually way rich. If you knew the afr that you were getting compaired to the comanded you would have a better idea as to were to look for the problem. I am thinking both sides are running lean at WOT, and one side is running lean enough to make the NB switch were as the other is just before or past the switching. If you knew if both sides were lean or if only one side was then you would know what route to take to trouble shoot the problem. Did you run compression when you had the plugs out like I suggested? In order to trouble shoot you need to proove things are right as well as things are bad. It does not matter to me, we can assume all day long the issue is only on one side because we are assuming the NB are correct. I for one hait to Assume (*** U Me) anything because it usually turns out the way its spelled.
So before you do the WB thing, lets look at the basics, Did you run compression when you had the plugs out? What was it?
So before you do the WB thing, lets look at the basics, Did you run compression when you had the plugs out? What was it?
07-07-2009, 09:47 AM
#48
Do you infact know if the engine is running lean or rich? A stock tune is usually way rich. If you knew the afr that you were getting compaired to the comanded you would have a better idea as to were to look for the problem. I am thinking both sides are running lean at WOT, and one side is running lean enough to make the NB switch were as the other is just before or past the switching. If you knew if both sides were lean or if only one side was then you would know what route to take to trouble shoot the problem. Did you run compression when you had the plugs out like I suggested? In order to trouble shoot you need to proove things are right as well as things are bad. It does not matter to me, we can assume all day long the issue is only on one side because we are assuming the NB are correct. I for one hait to Assume (*** U Me) anything because it usually turns out the way its spelled.
So before you do the WB thing, lets look at the basics, Did you run compression when you had the plugs out? What was it?
So before you do the WB thing, lets look at the basics, Did you run compression when you had the plugs out? What was it?
The engine is stock, the tune is stock, there is NO need for a wideband to troubleshoot it. Do you think tech's at dealers fixing issues like this every day work with widebands? Nope, they use the sensors the car was built with.
To the original poster, have you tried disabling the MAF to see what happens to fuel? In my car when it was completely stock, my part throttle fuel trims were pretty decent with the stock MAF, but as soon as I opened the throttle up and airflow went up, the car went lean and pinged, the MAF was at fault. My O2 sensors were behaving a lot like yours are now...I know it seems like it's only on one bank, but I think it's worth a shot, it's easy enough to unplug it and log a run (the car will run on the low octane tables while it's unplugged).
The next thing I would look at, since the AIR and EGR have been disabled and blocked off, would be a clogged cat (didn't these cars have a TSB regarding issues clogging stock cats? I can't remember). I do not think it's clogged because of those mods, I just think that any leaks or anything else related to those mods are already ruled out, and it's very possible that the cat on one bank is partially clogged, and much more of an obstruction at high airflow than at low airflow.
I am at work so I can't pull up your logs right now, what are your rear O2 sensors showing at part throttle and full throttle? Is bank 1 sensor 2 reading a lot different than bank 2 sensor 2?
07-07-2009, 10:03 AM
#49
Haven't run a comp check yet. I previously only pulled plugs on bank 1. I started tearing back into it the other night. Still have to pull plug #8, then I will run the comp check.
I'm pretty confident you are misunderstanding the operation of the O2 sensor. The sensor itself does not switch. Its readout shows the PCM commanding fueling changes. Those changes are made based on O2 readings. In part throttle, the PCM wants to maintain 14.7:1 so when the O2 shows richer, PCM pulls fuel until the O2 shows leaner and PCM adds fuel. The O2 simply tells the PCM whats going on, it does not actually switch the fueling. So in WOT, the O2s should flatline because PCM fueling is based on PE tables. This car is leaning out, the "switching" you see in my logs has nothing to do with the O2 (I swapped O2s to verify). Since the PCM is in PE mode, fueling isn't switching either. The variation in O2 reading on bank 1 is, in my assumption, a visual display of an unintended action. What is happening is not being commanded. The purpose of my post was to try and figure out what is causing this unintended action.
07-07-2009, 10:06 AM
#51
To the original poster, have you tried disabling the MAF to see what happens to fuel? In my car when it was completely stock, my part throttle fuel trims were pretty decent with the stock MAF, but as soon as I opened the throttle up and airflow went up, the car went lean and pinged, the MAF was at fault. My O2 sensors were behaving a lot like yours are now...I know it seems like it's only on one bank, but I think it's worth a shot, it's easy enough to unplug it and log a run (the car will run on the low octane tables while it's unplugged).
The next thing I would look at, since the AIR and EGR have been disabled and blocked off, would be a clogged cat (didn't these cars have a TSB regarding issues clogging stock cats? I can't remember). I do not think it's clogged because of those mods, I just think that any leaks or anything else related to those mods are already ruled out, and it's very possible that the cat on one bank is partially clogged, and much more of an obstruction at high airflow than at low airflow.
I am at work so I can't pull up your logs right now, what are your rear O2 sensors showing at part throttle and full throttle? Is bank 1 sensor 2 reading a lot different than bank 2 sensor 2?
Clogged cat is still a possibility, but the block offs have only been installed for about 50 miles of run time.
O2s look fine to me at part throttle.
07-07-2009, 10:30 AM
#52
Looks like I am slowing the thread down on helping you find the problem. I am sorry for that, that was not my intention. I will back out of this and I hope you find the issue soon.
As far as missing a few details, yeh its easy to miss when I am reading, typing, and driving at the same time.
Good luck and I hope you figure the issue out soon.
As far as missing a few details, yeh its easy to miss when I am reading, typing, and driving at the same time.
Good luck and I hope you figure the issue out soon.
07-07-2009, 11:08 AM
#54
True it is a bad habit, at least I am not doing it in Houston traffic. Out here in the desert there is hardly any one elso on these rodes.
I only wanted to use the WB to verify the issue was or was not only on one bank, but that is a lot of work that is probly not neccesary. If it is comen then MAF, fule filter, Fuel pump, things that would effect both banks makes sense. If it is only lean on one bank then I would think it would have to be something like a coil, wirring to one of the coils, bad injector, plugged cat, spark plug, plug wire (which you already checked both of those), bad valve, weak cylinder, bad rocker, or a bent pushrod (all of those you should be able to eliminate with a compression check). I have no idea how to test for a bad injecter or coil. Maybe it will show up with a balance test ran from the scanner. Have you done this? If you can nail it down to just that bank for sure, you might even (latter after testing the easier things first) you might have to pull the valve cover to look for a broken spring or lay a straight edge over the tips of the valves to see if there is any valve resesion on one of hte vavles. A bad spring could cause this type of condition at higher rpms. A resest vavle could close up the clearence in the Hydrolic lifter and it might be pumping up enough to hold the valve open at higher rpms. All of that is something I would work towards checking latter. Do the symple checks first. I bet you will find the problem is something symple that we are overlooking.
I stoped on the side of the rode to right all of this by the way.
I only wanted to use the WB to verify the issue was or was not only on one bank, but that is a lot of work that is probly not neccesary. If it is comen then MAF, fule filter, Fuel pump, things that would effect both banks makes sense. If it is only lean on one bank then I would think it would have to be something like a coil, wirring to one of the coils, bad injector, plugged cat, spark plug, plug wire (which you already checked both of those), bad valve, weak cylinder, bad rocker, or a bent pushrod (all of those you should be able to eliminate with a compression check). I have no idea how to test for a bad injecter or coil. Maybe it will show up with a balance test ran from the scanner. Have you done this? If you can nail it down to just that bank for sure, you might even (latter after testing the easier things first) you might have to pull the valve cover to look for a broken spring or lay a straight edge over the tips of the valves to see if there is any valve resesion on one of hte vavles. A bad spring could cause this type of condition at higher rpms. A resest vavle could close up the clearence in the Hydrolic lifter and it might be pumping up enough to hold the valve open at higher rpms. All of that is something I would work towards checking latter. Do the symple checks first. I bet you will find the problem is something symple that we are overlooking.
I stoped on the side of the rode to right all of this by the way.
07-07-2009, 11:40 AM
#56
Cylinder balance test is in VCM scanner (same page the CASE learn is on...advanced controls I believe)...if an injector is clogged or leaking it'll show you. What it does is tell you to take over the IAC with the real time controls to stabilize RPM (I usually bring the RPM up off idle a good bit to further stabilize it). It then shuts the 8 injectors off in order 1 at a time and records the RPM difference as a % of the original RPM...if one results in a much different change than the rest you have found a problem.
How did you clean the MAF...I've seen some people have very good luck cleaning them with a q-tip, and others damage them beyond being usable anymore.
Have you tried any logging in open loop before the car is able to get into closed loop? You could try disabling closed loop (unplug an O2 sensor or just flash quick with the closed loop enable temp jacked way up), clear the fuel trims, and then see what happens in open loop...that'd kinda be shooting from the hip though, I don't think it'd actually find a problem.
Like I said too...I don't think disabling the emissions equipment would be the direct cause of a clogged cat...I just think it was clogged to begin with. My car hasn't had AIR or EGR for 60 or 70K miles now...and it's cats aren't clogged as a result...but like I also said, I believe there was a technical service bulletin for some of these cars if not all of them, regarding issues with the stock catalytic converts clogging...it's very possible that th eonly reason mine aren't clogged is that they might have been replaced before I bought the car, I don't know.
How did you clean the MAF...I've seen some people have very good luck cleaning them with a q-tip, and others damage them beyond being usable anymore.
Have you tried any logging in open loop before the car is able to get into closed loop? You could try disabling closed loop (unplug an O2 sensor or just flash quick with the closed loop enable temp jacked way up), clear the fuel trims, and then see what happens in open loop...that'd kinda be shooting from the hip though, I don't think it'd actually find a problem.
Like I said too...I don't think disabling the emissions equipment would be the direct cause of a clogged cat...I just think it was clogged to begin with. My car hasn't had AIR or EGR for 60 or 70K miles now...and it's cats aren't clogged as a result...but like I also said, I believe there was a technical service bulletin for some of these cars if not all of them, regarding issues with the stock catalytic converts clogging...it's very possible that th eonly reason mine aren't clogged is that they might have been replaced before I bought the car, I don't know.
Last edited by Mike454SS; 07-07-2009 at 11:45 AM.
07-07-2009, 12:57 PM
#59
Cylinder balance test is in VCM scanner (same page the CASE learn is on...advanced controls I believe)...if an injector is clogged or leaking it'll show you. What it does is tell you to take over the IAC with the real time controls to stabilize RPM (I usually bring the RPM up off idle a good bit to further stabilize it). It then shuts the 8 injectors off in order 1 at a time and records the RPM difference as a % of the original RPM...if one results in a much different change than the rest you have found a problem.
How did you clean the MAF...I've seen some people have very good luck cleaning them with a q-tip, and others damage them beyond being usable anymore.
Have you tried any logging in open loop before the car is able to get into closed loop? You could try disabling closed loop (unplug an O2 sensor or just flash quick with the closed loop enable temp jacked way up), clear the fuel trims, and then see what happens in open loop...that'd kinda be shooting from the hip though, I don't think it'd actually find a problem.
Like I said too...I don't think disabling the emissions equipment would be the direct cause of a clogged cat...I just think it was clogged to begin with. My car hasn't had AIR or EGR for 60 or 70K miles now...and it's cats aren't clogged as a result...but like I also said, I believe there was a technical service bulletin for some of these cars if not all of them, regarding issues with the stock catalytic converts clogging...it's very possible that th eonly reason mine aren't clogged is that they might have been replaced before I bought the car, I don't know.
How did you clean the MAF...I've seen some people have very good luck cleaning them with a q-tip, and others damage them beyond being usable anymore.
Have you tried any logging in open loop before the car is able to get into closed loop? You could try disabling closed loop (unplug an O2 sensor or just flash quick with the closed loop enable temp jacked way up), clear the fuel trims, and then see what happens in open loop...that'd kinda be shooting from the hip though, I don't think it'd actually find a problem.
Like I said too...I don't think disabling the emissions equipment would be the direct cause of a clogged cat...I just think it was clogged to begin with. My car hasn't had AIR or EGR for 60 or 70K miles now...and it's cats aren't clogged as a result...but like I also said, I believe there was a technical service bulletin for some of these cars if not all of them, regarding issues with the stock catalytic converts clogging...it's very possible that th eonly reason mine aren't clogged is that they might have been replaced before I bought the car, I don't know.
As for MAF cleaning, I just sprayed it with MAF cleaner. I didn't touch the elements.
07-07-2009, 01:09 PM
#60
Have you tried any logging in open loop before the car is able to get into closed loop? You could try disabling closed loop (unplug an O2 sensor or just flash quick with the closed loop enable temp jacked way up), clear the fuel trims, and then see what happens in open loop...that'd kinda be shooting from the hip though, I don't think it'd actually find a problem.