School me on O2 switchpoints

[ddnspider]

I have performed AutoMAF and AutoVE several times and the car seems to run pretty good. I just took a look at my LTFT's and they look pretty good except for at idle where its down in the 500-600rpm range, and at WOT. I was originally getting the lazy O2 code's with the long tube headers until I switched to the Bosch Corvette O2's, then everything was okay.I also updated my O2 switchpoints in an attempt to bring the idle LTFT's closer to zero. Can you guys take a look at my log and O2 switchpoint table and let me know what you think? PS, I did not have a wideband on the car during the log.

PS Car is a 1998 Z28 A4 with intake and exhaust.

[ddnspider]

Bump!!! Looking for input. Doing a search gives me bits and pieces and I found more info over on HP Tuners than I did here unfortunately.

[ScarabEpic22]

Set all to 450mv, if you're trying to adjust them to 0 LTFTs that is NOT the way to do it. Could always go OL for idle and not worry about it, or disable LTFTs altogether (if your tune is correct, you dont really need them).

[ddnspider]

Set all to 450mv, if you're trying to adjust them to 0 LTFTs that is NOT the way to do it. Could always go OL for idle and not worry about it, or disable LTFTs altogether (if your tune is correct, you dont really need them).

Can you give input into why other threads show people logging and trying to adjust them based on the airflow levels.

[joecar]

Can you give input into why other threads show people logging and trying to adjust them based on the airflow levels.Can you post some links.

[ddnspider]

Can you post some links.

Just a few examples from a google search...
http://www.hptuners.com/forum/showthread.php?t=11333

http://www.hptuners.com/forum/showthread.php?t=36956

http://forum.efilive.com/archive/index.php/t-8515.html

I am trying to understand the following:

A) I've performed AutoVE and AutoMAF several times and the car runs pretty good. However, I seem to have +LTFT's ~5% at low idle (550rpms) and at WOT, everywhere else looks really nice. How would moving the O2 switch points around in the idle and high airflow ranges affect this?

B) What is the best way to go about logging this or doing a map? Are there any tutorials?

C) Alot of people seem to have issues doing this or, should I say, need to do this when adding long tubes due to O2 placement. I posted a pic when I exported my O2 voltage and airflow to an excel and manually sorted and tried to average, but it is definitely not 450mV across the board. Does it look wrong?

[Gregs]

Just a few examples from a google search...
http://www.hptuners.com/forum/showthread.php?t=11333

http://www.hptuners.com/forum/showthread.php?t=36956

http://forum.efilive.com/archive/index.php/t-8515.html

I am trying to understand the following:

A) I've performed AutoVE and AutoMAF several times and the car runs pretty good. However, I seem to have +LTFT's ~5% at low idle (550rpms) and at WOT, everywhere else looks really nice. How would moving the O2 switch points around in the idle and high airflow ranges affect this?

B) What is the best way to go about logging this or doing a map? Are there any tutorials?

C) Alot of people seem to have issues doing this or, should I say, need to do this when adding long tubes due to O2 placement. I posted a pic when I exported my O2 voltage and airflow to an excel and manually sorted and tried to average, but it is definitely not 450mV across the board. Does it look wrong?

A) I'm a little confused, you want to adjust your AFR by moving the switchpoints? I played around with switchpoints a long time ago and found that its best to have them all set to 450 mV. At WOT your o2 sensors aren't part of the equation so you probably need to adjust the top part of your MAF curve to fix that problem. For idle I would really not be concerned with having a slightly off LTFT, however having a cam changes things a little bit for me.

B) yes there are tutorials included in the efilive documentation.

C) I don't have longtubes so i haven't had to mess with adjusting the o2's for them. Honestly right now I'm running with MAF enabled and no 02's; I've had my best results doing it that way. If i had headers I would definitely forget using o2's. They add an extra layer of complexity and reduce reliability, I don't think they're necessary.

[Gregs]

I also updated my O2 switchpoints in an attempt to bring the idle LTFT's closer to zero.

Adjusting the switchpoints is the wrong procedure to fix this issue, set all switchpoints to 450 mV and tune the VE and MAF tables.

[ddnspider]

A) I'm a little confused, you want to adjust your AFR by moving the switchpoints? I played around with switchpoints a long time ago and found that its best to have them all set to 450 mV. At WOT your o2 sensors aren't part of the equation so you probably need to adjust the top part of your MAF curve to fix that problem. For idle I would really not be concerned with having a slightly off LTFT, however having a cam changes things a little bit for me.

B) yes there are tutorials included in the efilive documentation.

C) I don't have longtubes so i haven't had to mess with adjusting the o2's for them. Honestly right now I'm running with MAF enabled and no 02's; I've had my best results doing it that way. If i had headers I would definitely forget using o2's. They add an extra layer of complexity and reduce reliability, I don't think they're necessary.

For B), I know there are tutorials about setting up a MAP in general. I am looking for more information regarding how I would setup a MAP for this specific thing. Meaning, would I plot O2 mV data for WB02 A/F vs. airflow?

[joecar]

+1 for setting the switch points to 450 mV.

[joecar]

For B), I know there are tutorials about setting up a MAP in general. I am looking for more information regarding how I would setup a MAP for this specific thing. Meaning, would I plot O2 mV data for WB02 A/F vs. airflow?Create maps of HO2S11 and HO2S21 with LTFT's and MAF on the axes...

to do this follow the map tutorial, just change the pids used on the Data, Row, Col tabs...

let me know if you get stuck.

[ddnspider]

Create maps of HO2S11 and HO2S21 with LTFT's and MAF on the axes...

to do this follow the map tutorial, just change the pids used on the Data, Row, Col tabs...

let me know if you get stuck.

Thanks Joe. I should be good with creating the MAP as I've done that before. I was getting stuck with this in particular because you're really referencing 2 different tables with 1 MAP. 1 is closed loop mode vs O2 mV and the other is g/sec MAF vs. Closed Loop Mode.

[Gregs]

For B), I know there are tutorials about setting up a MAP in general. I am looking for more information regarding how I would setup a MAP for this specific thing. Meaning, would I plot O2 mV data for WB02 A/F vs. airflow?

I must be missing something... Why are you wanting to mess with the o2 switch points at all? To tune the Maf it would be maffreq on the y-axis and populate the table with the Ben from your wideband. Oh wait I think it just clicked, are you trying to tune this car with your nb02 ?

[ddnspider]

I must be missing something... Why are you wanting to mess with the o2 switch points at all? To tune the Maf it would be maffreq on the y-axis and populate the table with the Ben from your wideband. Oh wait I think it just clicked, are you trying to tune this car with your nb02 ?

Sorry, perhaps I dug too deep too quickly and didnt lay enough foundation for my thought process. My gears initially started turning when I did long tube headers on my 98 z28 A4. I performed AutoVE and AutoMAF several times with a WB02 with good results. But when the system went back into closed loop, my O2's were adding LTFT's at idle that disagreed with my WB02. I did searching and found that this has happened to many people, usually because of moving the O2's placement from factory.

There was 1 particular thread on here that I cannot seem to find, where someone in a corvette was having the same issues. They did AutoVE and MAF and had his fueling within a couple percent, but when he went back closed loop, his narrowband O2's were adding LTFT's that disagreed with his WB02 and he found he had to sample and tweak his O2 switch points. This is basically where my thought process went and I figured I needed to do the same.

[joecar]

Thanks Joe. I should be good with creating the MAP as I've done that before. I was getting stuck with this in particular because you're really referencing 2 different tables with 1 MAP. 1 is closed loop mode vs O2 mV and the other is g/sec MAF vs. Closed Loop Mode.That reminds me of this: B4105-how-do-i-link-this-table (http://forum.efilive.com/showthread.php?8142-B4105-how-do-i-link-this-table)

[ddnspider]

That reminds me of this: B4105-how-do-i-link-this-table (http://forum.efilive.com/showthread.php?8142-B4105-how-do-i-link-this-table)

Hmmmm, I will have to give that a look as I was not familiar with linking. Thanks for the link!

[maudyZ28]

OK, so to clarify, I'm gonna assume you WB at Idle is about 14.7 AFR ish and you are happy with this and your MAF/VE tune using the WB is good

However, back in closed loop you find LTFT wanting to add 5% more fuel at Idle compared to the WB, ie making the WB read lower than 14.7 AFR. So switching at 365 or 415 mv in CL mode 8 or 16 (IIRC) is still too high. If you set to 450 mv across the board it will add even more fuel in the LTFT (test this!).

With my headers, before cam I think I had my O2 switch at about 320 mv or something at idle airflows. I will check this weekend when I'm home.

The problem is that at idle the O2 do not switch fast like they do when driving, either that or mine are on there way out and being really slow. (they are fine at > 2000 rpms). This means that the fueling will swing up and down. To note, I cannot run CL with my heads/cam at low RPM as it causes hunting as the fueling is jumping up and down so much. In open loop where I specify the fueling, it is fine. Just food for thought. I run OLSD all the time with a innovate MTX WB in all the time to keep an eye on fuel which is band solid at 14.6-14.7 in general driving.

[ddnspider]

OK, so to clarify, I'm gonna assume you WB at Idle is about 14.7 AFR ish and you are happy with this and your MAF/VE tune using the WB is good

However, back in closed loop you find LTFT wanting to add 5% more fuel at Idle compared to the WB, ie making the WB read lower than 14.7 AFR. So switching at 365 or 415 mv in CL mode 8 or 16 (IIRC) is still too high. If you set to 450 mv across the board it will add even more fuel in the LTFT (test this!).

With my headers, before cam I think I had my O2 switch at about 320 mv or something at idle airflows. I will check this weekend when I'm home.

The problem is that at idle the O2 do not switch fast like they do when driving, either that or mine are on there way out and being really slow. (they are fine at > 2000 rpms). This means that the fueling will swing up and down. To note, I cannot run CL with my heads/cam at low RPM as it causes hunting as the fueling is jumping up and down so much. In open loop where I specify the fueling, it is fine. Just food for thought. I run OLSD all the time with a innovate MTX WB in all the time to keep an eye on fuel which is band solid at 14.6-14.7 in general driving.
Yep, that about sums up what was going on. I could also tell that my O2's were switching slow at idle and they're basically brand new. This is why I've been hesitant to just set them to 450mV across the board. I'd prefer to stay closed loop to account for temp changes throughout the year. It's a 98 so I don't have some of the tables that later years do like IAT vs fuel adder.

[ddnspider]

up cho bác, chúc bác bán d?t hÃ*ng.

W....H...A....T??


PS...I'm also wondering if my "low" idle is also exacerbating this since the car idles at ~550rpm's, i.e. one of the causes of slow switcing at idle.

[maudyZ28]

W....H...A....T??


PS...I'm also wondering if my "low" idle is also exacerbating this since the car idles at ~550rpm's, i.e. one of the causes of slow switcing at idle.

The car lower idle will make switching slower and this is exacerbated by the headers being longer and larger in diameter too.

I run with the WB to check all the time, beauty of the MTX. However I do not see too much variation with weather but the UK is cold or cold and wet !!! I do a new retune for fueling every couple of months anyways.

Setting switch points to 450 across the board will be fine but will make it more rich at idle than now so you will have to prob set it at about 320 mv. You'll just have to fiddle a bit till you are happy

My NB are constantly dead at Idle as my AFR is about 14.8-14.9 with heads and cam, WB running lean with a mid overlap is about right, so it's tuned by feel here, if you get what I mean. My NB do an ok job but again causes some hunting cause of cam and my switch points are about 300-330 mv.

You'll just have to test it at idle till youre happy. Long as the +5% isn't added when driving then your fueling will be bang on anyway, well to stochiometic.

At WOT you will run soley off MAF or VE (if mafless) so that needs to be dialed in with the WB very well and No more fuel will be added as long as all other fuel trims are not +ve.

A cheating way to ensure WOT / PE mode is always as the WB is to richen fueling by 1% everywhere except the PE region. Thus in CL the LTFT will be -ve by a percent or two and hence at WOT only commanded fueling will be used as PE mode is not made leaner by -ve fuel trims.

[ddnspider]

I just got back from logging. I setup that calculated PID via JoeCar's linked thread. You can see my average O2's for each closed loop section. Even though the average isn't 450mV for each group should I still be setting them to 450mV?

I also made some changes to my trans shift points and reduced the knock recovery rate to .25 and it seemed to make a big difference in how the car drives and I can see from the logs that I'm consuming more lb/min of air, which is a nice plus :)

Comments welcome on the log.

1462114622

[EagleMark]

When you install long tube headers and move the O2 sensor the readings it's getting are in wrong part of exhaust flow ie.. should have picked up correction but now, it's not and correcting again, then getting a reading and adjusting back.

I beleive this is B4113 STFT Base Delay in EFI Live. Needs to be increased. Time to O2 sensor has changed.

Setting all swing points to .451 does help with data and stabilise AFR, what would really stablise AFR would be the O2 low and O2 high points to tighten up the swing... but that paremeter is not in there... yet...

[ddnspider]

When you install long tube headers and move the O2 sensor the readings it's getting are in wrong part of exhaust flow ie.. should have picked up correction but now, it's not and correcting again, then getting a reading and adjusting back.

I beleive this is B4113 STFT Base Delay in EFI Live. Needs to be increased. Time to O2 sensor has changed.

Setting all swing points to .451 does help with data and stabilise AFR, what would really stablise AFR would be the O2 low and O2 high points to tighten up the swing... but that paremeter is not in there... yet...

Can you provide some information regarding how much to increase B4113? I assume this would mainly be in the 0 and 8 closed loop modes?

Also, when you said "what would really help stabilize AFR would be O2 low and high points to tighten up the swing", isnt that basically what moving the O2 switch point around does?

[EagleMark]

I have no scietific measurment for exhaust flow speed to msec, normally I just measure how far O2 sensor moved and try to adjust by %. Going to big does not hurt, to small and the O2 sensor is reading exhaust that has not had fuel corection. Ends up as a yo yo effect...

There are O2 high and low voltage settings, not in EFI Live definition... yet.... hint... hint.... Then the switch point which is middle.

So high .900 low .100 and switch point at .451. Changing them to high .700 and low .300 with switch point of .451 tightens up Lambda/AFR swings. Works great!

I have many of these for older GM stuff, but need to learn dissasembly/assembly so I can find things that are missing in these new ones. I have a dissasembly of 98-00 Vortec and used the EFI Live cax file to add in all the missing paremeters.

[ddnspider]

I have no scietific measurment for exhaust flow speed to msec, normally I just measure how far O2 sensor moved and try to adjust by %. Going to big does not hurt, to small and the O2 sensor is reading exhaust that has not had fuel corection. Ends up as a yo yo effect...

There are O2 high and low voltage settings, not in EFI Live definition... yet.... hint... hint.... Then the switch point which is middle.

So high .900 low .100 and switch point at .451. Changing them to high .700 and low .300 with switch point of .451 tightens up Lambda/AFR swings. Works great!

I have many of these for older GM stuff, but need to learn dissasembly/assembly so I can find things that are missing in these new ones. I have a dissasembly of 98-00 Vortec and used the EFI Live cax file to add in all the missing paremeters.

It's feasible that the distance of the O2 from the cylinder head exhaust port is twice the distance it was stock, so you would roughly double the time in that table?

[Boost]

I am getting a P1153 insufficient switching. I wonder if it's due to mods or a tired sensor.

[ddnspider]

I am getting a P1153 insufficient switching. I wonder if it's due to mods or a tired sensor.

I got that code regularly after I did my longtubes. I put the Bosch corvette rear O2's that alot of people switch to and my problem went away.

[Boost]

thanks!!!

[Boost]

I got that code regularly after I did my longtubes. I put the Bosch corvette rear O2's that alot of people switch to and my problem went away.

Actually we already have those installed for the longtubes, and it's still doing it. I may need to adjust the tune. (?)

[ddnspider]

Actually we already have those installed for the longtubes, and it's still doing it. I may need to adjust the tune. (?)

Is the tune stock? I know it definitely stopped after I did the AutoVE and MAF tuning and messed with the O2 switchpoints. It also sounds like EagleMark's comment about adjusting the STFT timing would also help with that since it would allow more time before it tries to read the O2's.


Morning bump for anyone who wants to comment on the log I uploaded.

[Boost]

Definitely. The tune is a progress based on Shawn's work. The switchpoints and stuff needs a adjstment, I will read over this thead several times and experiment in the days to come.

[ddnspider]

Definitely. The tune is a progress based on Shawn's work. The switchpoints and stuff needs a adjstment, I will read over this thead several times and experiment in the days to come.

Post back what you find out.

[maudyZ28]

I am getting a P1153 insufficient switching. I wonder if it's due to mods or a tired sensor.

Interesting, i've never got that with long tubes and full true duals , 3 inch diameter with no cats. Even with 228/228 cam in there there is no problem.....

How do the O2's look when driving above 3000 rpm, they should be fluctuating very rapidly. One thing maybe with the headers is that the O2 bungs dont put the sensors in the gas flow enough and are slow to respond. This is just a theory as mine seem to be fine and that is with the standard bungs the headers came with.

I'm gonna take a look through the log spider and get back to you :D

[ddnspider]

Interesting, i've never got that with long tubes and full true duals , 3 inch diameter with no cats. Even with 228/228 cam in there there is no problem.....

How do the O2's look when driving above 3000 rpm, they should be fluctuating very rapidly. One thing maybe with the headers is that the O2 bungs dont put the sensors in the gas flow enough and are slow to respond. This is just a theory as mine seem to be fine and that is with the standard bungs the headers came with.

I'm gonna take a look through the log spider and get back to you :D

Thanks Maudy......and I would also agree with your comment about o2 depth. I noticed when I screwed mine in that they were not in the exhaust tract as much as the stock bung.....but then again I have Chinese long tubes since this is my experimental car lol.

[maudyZ28]

log looks fine, no knock at WOT which is good, you actually run very similar timing to me. I've also manage to push mine up to 28 deg above 5200 rpm on 99 RON fuel without knock. Still gonna get it up on the dyno soon, brakes to sort out first, make sure I can stop before going faster.

With your switch points you can goto 450 everywhere, the only reason they are different is the it will run slightly richer or leaner (above or below 450 mv) in different CL modes which relate to different load amounts. Still I dont really think there is much of an issue, look at a Z06 tune or even a c5, there switch points are different again.

I did notice you had an LC1 connected, is that reading right? I dont know if my PIDs are the same as yours but it was giving a BEN of 0.5 which is way wrong. BEN should be 1 either calced from WB or NB if all are to agree

[ddnspider]

I'm running a stock 98 table, which seems to be more aggressive than the later years from what I gather. I see a hunt of knock at WOT so I think I'll have to pull a degree or so and see if that clears it up.

If I change all my switch points to 450mV will I have to go back and retune everything?

I didn't have the LC1 installed which is why the BEN was way off :)

[maudyZ28]

I'm running a stock 98 table, which seems to be more aggressive than the later years from what I gather. I see a hunt of knock at WOT so I think I'll have to pull a degree or so and see if that clears it up.

If I change all my switch points to 450mV will I have to go back and retune everything?

I didn't have the LC1 installed which is why the BEN was way off :)


At 450 mv the NB should be at about 14.63 AFR, the differenced in a few tens of mv is not too great. If you tuned with WB then NB will be pretty close. The NB use for closed loop adjustment only so it will run to the sensors and not your tune. Obviously you know your tune is pretty close as the LTFT are only a few %. Its really upto you

Yeah the 98 table is more aggressive. I didnt see any knock more than about 1 deg or so? And if you look carefully its when you change gear so could be drive line knock, mine used to do this all the time on an older loose diff I had in, How hot was it when you ran cause your IAT are quite high?

Also check out the burst knock and comopulsary knock. I was sure 98 timing ran 28* at 5500 or above and your running 26. This maybe due to temp, the car pulling timing as standard or the merging of spar tables depending on your fuel quality. Just food for thought, I always like to know exactly where my timing is coming from :)

[ddnspider]

At 450 mv the NB should be at about 14.63 AFR, the differenced in a few tens of mv is not too great. If you tuned with WB then NB will be pretty close. The NB use for closed loop adjustment only so it will run to the sensors and not your tune. Obviously you know your tune is pretty close as the LTFT are only a few %. Its really upto you

Yeah the 98 table is more aggressive. I didnt see any knock more than about 1 deg or so? And if you look carefully its when you change gear so could be drive line knock, mine used to do this all the time on an older loose diff I had in, How hot was it when you ran cause your IAT are quite high?

Also check out the burst knock and comopulsary knock. I was sure 98 timing ran 28* at 5500 or above and your running 26. This maybe due to temp, the car pulling timing as standard or the merging of spar tables depending on your fuel quality. Just food for thought, I always like to know exactly where my timing is coming from :)

I did the original tuning with a WB. I guess maybe I still don't fully grasp the O2 switchpoints then. I thought you tweaked them to so that the PCM reaches the A/F you want it to be at, i.e. if the headers are causing slow switching and giving you a richer idle, then if you move the switchpoint up it will make the PCM run a leaner mixture. Feel free to correct/enlighten me.

As far as knock, on my latest log I posted (not the one in my original post) I see it at the gear change, but it also pops up elsewhere so I think that may be real or may just not have a high enough threshold since its a 98 and they're prone to false knock.

My stock high octane table commands 26* in the dyncynair columns that I reach at WOT so it is pulling a bit due to the "knock". My burst knock table is zero'd out, but I haven't heard of the compulsary knock. What is that and what table number is it? I noticed a hugh improvement in knock when I upped the recovery rate to .25 so it would immediately put back in timing when the "knock" stopped.

I am also curious if anyone has significantly decreased the attack rate to say 1 degree per volt.

[maudyZ28]

OK, with regards to the switch points you have the correct idea. A NB sensor only switches between rich and lean at 450 mv - AFR ~ 14.63. Anything higher will run richer and anything lower will run leaner. BUT....only very very slightly as the switch point is only moved a few mv. This is in normal driving when the gas flow is such that the NB are switching rapidly. As you correctly identified before in different CL modes your switch points are slightly different. Meaning if you put a WB in, just for monitoring now then the AFR average in each CL mode should differ, again only very slightly. But pretty much about 14.63. Hence why everyone just sets them to 450 mv across all CL modes

Now the changing of the switch points at idle is more of a trick...or a cheat? Either way, due to the slow gas flow with having headers of a larger diameter and the NB further away the idle AFR maybe off. So when you compare with the WB you might not see 14.63 exactly. So now with the stock NB switch point the LTFT is +5%. But this could mean the tune is off at idle OR the switch points are too high. If your WB says 14.63 at idle then in CL it says +5% LTFT at idle then reduce the switch point to compensate for the extra fuel the car thinks it needs due to slow switching. Always double check with the WB sensor. Seriously the innovate MTX has been brilliant in mine and I can keep check of the WB AFR. What does you WB show? Does the car run well at idle regardless?

Ah ok with the 26* at WOT, not looked at my tune for a while, been sorting brakes and building an axle. I'm sure there was a table in the knock section that says in the description, amount of knock to pull regardless of condition. Will have to check which table but wont be able to access my tune laptop for a few days :S. If you've sorted burst knock and ramp rate then all should be good. :)

[ddnspider]

OK, with regards to the switch points you have the correct idea. A NB sensor only switches between rich and lean at 450 mv - AFR ~ 14.63. Anything higher will run richer and anything lower will run leaner. BUT....only very very slightly as the switch point is only moved a few mv. This is in normal driving when the gas flow is such that the NB are switching rapidly. As you correctly identified before in different CL modes your switch points are slightly different. Meaning if you put a WB in, just for monitoring now then the AFR average in each CL mode should differ, again only very slightly. But pretty much about 14.63. Hence why everyone just sets them to 450 mv across all CL modes

Now the changing of the switch points at idle is more of a trick...or a cheat? Either way, due to the slow gas flow with having headers of a larger diameter and the NB further away the idle AFR maybe off. So when you compare with the WB you might not see 14.63 exactly. So now with the stock NB switch point the LTFT is +5%. But this could mean the tune is off at idle OR the switch points are too high. If your WB says 14.63 at idle then in CL it says +5% LTFT at idle then reduce the switch point to compensate for the extra fuel the car thinks it needs due to slow switching. Always double check with the WB sensor. Seriously the innovate MTX has been brilliant in mine and I can keep check of the WB AFR. What does you WB show? Does the car run well at idle regardless?

Ah ok with the 26* at WOT, not looked at my tune for a while, been sorting brakes and building an axle. I'm sure there was a table in the knock section that says in the description, amount of knock to pull regardless of condition. Will have to check which table but wont be able to access my tune laptop for a few days :S. If you've sorted burst knock and ramp rate then all should be good. :)

Thanks for the information. I need to throw the wideband back on the car to verify. Just to clarify and make sure I understand, if you have positive LTFT's at idle and the wideband says you're A/F is good, then you would LOWER the switchpoint, because it would mean that more of the O2 time is spent on the rich side and less on the lean side of the switchpoint? I assume you would check this with zero'd out/reset LTFT's to see what the wideband says without being influenced by LTFT's?

Just out of curiosity, what is your car that has the LS1 in?

[maudyZ28]

exactly what it should do.

Be very careful to disable all fuel trimming when tuning with the WB. The auto VE tutorials tell you what you need to dissable and what is providing your fueling.

I run a 99 camaro , I assume you run a 98 camaro or TA ?

[ddnspider]

exactly what it should do.

Be very careful to disable all fuel trimming when tuning with the WB. The auto VE tutorials tell you what you need to dissable and what is providing your fueling.

I run a 99 camaro , I assume you run a 98 camaro or TA ?

Per the AutoVE and AutoMAF tutorials I disabled all LTFT's and STFT's when using the wideband so they do not mess with my VE or MAF values. Then I turned them back on to go in closed loop. Technically, they SHOULD be zero if my VE and MAF changes were close, and per my log they're pretty close other than idle and WOT. Did I miss something?

I have a 10 Second 1998 TA M6 thats turbocharged and fully built. Been on a few magazine covers. I had someone tune that a long time ago. I've been wanting to get into tuning so found a good deal on a 1998 Z28 A4 that was basically stock, which I thought would be a better starting point to learning than the TA thats heavily modded lol. However, after looking at the tune in the TA I'm tempted to completely redo it, but its tough to tune a boosted 98 properly cause of the PCM limitations.

[maudyZ28]

Everything you have done is totally correct.

As we discussed, idle will be off due to slow switching. So if you are happy the WB says it is the correct AFR then you can tweak the NB switch points to get a better CL AFR. If the +5% LTFT makes a noticeable difference.

The second +ve trims at WOT are due to the fact that the PCM will add fuel trims from general CL driving to any fueling added at WOT to be safe. However the PCM will NEVER pull out fuel, so if you have -ve fuel trims then the PCM will only run at WOT direct from the MAF or VE table only. If your trims are about zero, then just add to your VE and MAF by say 0.5% (but not in WOT/PE areas) so the CL trims go negative and thus never add fuel to the WOT region where you have WB tuned

10s TA sounds awesome dude. Hoping to break 11s with my head/cam camaro. I dont know the specifics of the 98 PCM as I was lucky with a 99 and have upgraded to COS3 so can run a 3 bar map sensor and boost VE table if I wanted.....you thought about re-pinning a 99 PCM ?

[ddnspider]

Everything you have done is totally correct.

As we discussed, idle will be off due to slow switching. So if you are happy the WB says it is the correct AFR then you can tweak the NB switch points to get a better CL AFR. If the +5% LTFT makes a noticeable difference.

The second +ve trims at WOT are due to the fact that the PCM will add fuel trims from general CL driving to any fueling added at WOT to be safe. However the PCM will NEVER pull out fuel, so if you have -ve fuel trims then the PCM will only run at WOT direct from the MAF or VE table only. If your trims are about zero, then just add to your VE and MAF by say 0.5% (but not in WOT/PE areas) so the CL trims go negative and thus never add fuel to the WOT region where you have WB tuned

10s TA sounds awesome dude. Hoping to break 11s with my head/cam camaro. I dont know the specifics of the 98 PCM as I was lucky with a 99 and have upgraded to COS3 so can run a 3 bar map sensor and boost VE table if I wanted.....you thought about re-pinning a 99 PCM ?

Thanks Maudy, Good luck with 11's on your camaro. I am sure you'll get there. I have thought about repinning to a 99PCM. The car has been "finished" for over years so I guess the thought of repinning the PCM and starting from scratch on the tune is a bit daunting to me. It would be nice to have it tuned properly as I can tell from its current tune that the PE and IFR tables were raped lol.

[ferocity02]

I have a question on switchpoints. It is generally agreed to change the switchpoints to 450mV across the board. Is this from the fact that 450mV is halfway between 0 and 900mv?

What if the sensors never get up to 900mV when switching? Mine rarely get past 800mV. They are Delphi units with about 10k miles on them.

Perhaps the switchpoints should be tailored to the sensors rather than fixed at 450mv?

On a sidenote, is there a "best" O2 sensor out there? I am not opposed to changing mine if they should indeed be more active than they are.

[ddnspider]

I have a question on switchpoints. It is generally agreed to change the switchpoints to 450mV across the board. Is this from the fact that 450mV is halfway between 0 and 900mv?

What if the sensors never get up to 900mV when switching? Mine rarely get past 800mV. They are Delphi units with about 10k miles on them.

Perhaps the switchpoints should be tailored to the sensors rather than fixed at 450mv?

On a sidenote, is there a "best" O2 sensor out there? I am not opposed to changing mine if they should indeed be more active than they are.

Thats where I was originally coming from. Assuming your OLFA is close to what you want, then you should be able to log and see what your average switchpoint is based on the groupings and then set the tune for that. I know my O2's are lazy at idle due to the long tubes so I have my 2 lowest groups set below 450mV.

[ferocity02]

Thats where I was originally coming from. Assuming your OLFA is close to what you want, then you should be able to log and see what your average switchpoint is based on the groupings and then set the tune for that. I know my O2's are lazy at idle due to the long tubes so I have my 2 lowest groups set below 450mV.

For fun I set all of my switchpoints to 370 mV and there was no appreciable difference in AFR, it was still around 14.4 while cruising. But the average NBO2 voltage went down from like 460mV to 395mV. Not sure what to learn from this.

[voda1]

For fun I set all of my switchpoints to 370 mV and there was no appreciable difference in AFR, it was still around 14.4 while cruising. But the average NBO2 voltage went down from like 460mV to 395mV. Not sure what to learn from this.

Were the O2's cycling any faster?

[joecar]

Post log files of each (460mV, 395mV).

[ferocity02]

0049 is with 450mV switchpoints, 0051 is with 370mV switchpoints.

[ddnspider]

0049 is with 450mV switchpoints, 0051 is with 370mV switchpoints.

Interesting logs that your LTFT's are basically the same even with the switchpoint change.

[maudyZ28]

i need to have a look at those logs.

maybe test really low switch points about 300 mv ?

Do you verify AFR with a WB or just based upon LTFT...?

[ferocity02]

i need to have a look at those logs.

maybe test really low switch points about 300 mv ?

Do you verify AFR with a WB or just based upon LTFT...?

I used a WB in those logs, however I do not entirely trust it. I got an AEM wideband instead but haven't had time to try it again.

[maudyZ28]

doesnt appear to be a massive change but the average NB are reading lower, but only about 380 mv when SP are 370 and they read at 430 mv when SP are 450.
WB doesnt change mych either.

Also , I dont like how your NB are switching, they seem very choppy. Maybe its just me but mine are all nice and smooth up and down occilations, not jumpy. But I have headers now too...

[EagleMark]

Changing this entire B4105 table is just changing the switch point where the cross count occurs, noted as Initial Value in picture. Without the Lean and Rich or High and Low parameters it's not an effective tool for tuning AFR.

If I lower my entire table down to .200 range it will change Lambda from about .97 to .99. But can get a lot lower AFR by raising them to about .95 Lambda.

This is dependent on the O2 sensors which vary.

In a tune running Open Loop and using Lambda readings from Wide Band it was a steady 1.0

Go closed loop and let Narrow Bands do the adjustment and here's what I got from various O2 sensors.

Closed loop:
Bosch O2 sensors = .98
Second set of Bocsh O2 sensors = .99
AC Delco O2 sensors = 1.02
Denso O2 senor = .99

My real thought was AC/Delco O2 sensors are set lean to Stoich for MPG ratings?

Now if you had the Lean/Rich setting it works real well, also tightens up the swing you see in data dash. See pic...

I've been looking at all these settings trying to find a rhyme or reason in the way GM did these and there is none? Been changing them for years with excellent results shown in WB. Just recently was told by factory engineer the reason I could never find how/why/what? Was they are all just tweaked to whatever works best with the CAT for gas analyzer, has nothing to do with the AFR or way engine runs, although it will, at that point they don't care and it has to work with the design of the CAT and pass emissions for that YMM.

[Highlander]

That appears to be a tunerpro file.... care to share that xdf?