After opening the Tune Tool software and then opening up my .tun file, why is it that I can't see the tables for PID's like LTFT and Spark Advance? I see the VE table under the Fuel>Airflow folder but don't see any other tables like LTFT under the Fuel>Trim folder. If I can't see the table how can I make changes? I have no problem creating a LTFT table while in the scan tool mode but shouldn't I be able to see the same table while in tune tool mode?
Data contained in your .tun file is information that influences and controls the way your engine operates. Loosely speaking, it specifies instructions. Data that you scan is related to that but different. The PIDs you can scan represent operating state information, NOT instructions. They are two completely different animals.
Now the particular PIDs you're looking at are in fact feedback parameters. They represent the changes the PCM is making to your fueling in response to the information it sees from a variety of other sensors. The response is determined by your tune. The LTFT (and STFT) represent the system's deviation from the desired/target value specified by the stuff in your .tun. file.
You're missing a fairly fundamental idea, namely that the direct variable you measure (airflow) indirectly specifies the amount of fuel supplied. You'll notice that spark values are a little more directly specifed.
You might enjoy the book Corvette Fuel Injection & Electronic Engine Management 1982 through 2001, How to Understand, Service and Modify by Charles O. Probst, SAE. It has some inaccuracies and I definitely wouldn't call it hard core but it might give you enough of a lay of the land to get you started. Reading is always good when the snow is falling.
O.K. then. So I have a LTFT table created in scan tool that is showing positive % for the average values in the cells logged. I need to make some adjustments so that my LTFT's will get closer to zero or slightly negative, otherwise additional fuel will be added to what is already in the PE table for WOT operation. Since LTFT's represent adjustments made due to the STFT's (02 readings, closed loop) I can't directly adjust LTFT's. My question then is, what tables in my .tun file would I be looking at changing in order to get the LTFT's where I want them to be in order to not run rich at WOT?
All I'm trying to do is practive how to create tables in scan tool and then use the information to make changes to the appropriate table in the tune tool (the instruction) that will give me the actual values I want to see when I log data again.
I have read every single page of the scan and tune documentation as well as everything else available in EFILive and LS1Tech. Some like the AutoVE Tuning provide you with step by step instructions but it's a little too advanced for me at this point and I don't intend to run Mafless just yet.
There is a very good tutorial for HPTuner users I found in LS1Tech that provides a step by step approach. I believe that a lot of us newbies would really benefit from having a similar guide. I appreciate your response to my question and hope that you don't mind answering what you probably consider to be dumb questions.
O.K. then. So I have a LTFT table created in scan tool that is showing positive % for the average values in the cells logged. I need to make some adjustments so that my LTFT's will get closer to zero or slightly negative, otherwise additional fuel will be added to what is already in the PE table for WOT operation. Since LTFT's represent adjustments made due to the STFT's (02 readings, closed loop) I can't directly adjust LTFT's.
So far, so good. You're doing what the PCM would, examining the feedback and deciding what to do about it.
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My question then is, what tables in my .tun file would I be looking at changing in order to get the LTFT's where I want them to be in order to not run rich at WOT?
This is where is gets fun. You'll notice in my previous reply I indicated that the airflow was the primary input to determining the target amount of fuel. A digression into some history might be useful here.
Back in the day before programming was so readily available, about the only thing you could do was to tinker with the MAF signal. This signal indicates measured airflow. You may have heard of the MAF Translator gadget? It was designed to manipulate this signal with some simple circuitry so that the PCM would see increased or decreased airflow, depending on how the Translator was set up. The idea was to do the kind of data collection you've done and use that info to adjust the MAF Translator such that the LTFTs ended up where you wanted them.
Turns out that you can do something very similar via programming. You can adjust the MAF table in the same way in order to achieve the same effect. However, somewhere along the line you begin to wonder why you should need to adjust what are effectively calibration constants. It just feels wrong.
Once you have access to the PCM, Pandora's box is open and you start rummaging. You'll run across a table for injector flow rates, another calibration constant. Rather than lie about airflow we can lie about fuel flow, telling the PCM our injectors need to be on so long to deliver so much fuel. Again, the queasy feeling about altering calibration constants. It's probably even more incorrect than altering the MAF table on that point but with far fewer undesirable side effects. (The MAF signal is a key input to many other function and manipulating it for the purpose of achieving one particular objective, negative LTFTs in most cells, is missing the bigger picture.)
Now at this point, everybody is looking at the VE tables and scratching their head suspecting the answer might lie there, but not really knowing how to use or manipulate it. After all, everybody KNOWS that the VE tables are only referenced when the MAF is malfunctioning. However, if you change the volumetric efficiency of your engine (by adding headers for example) you believe that a table that describes the volumetric efficiency of the factory configuration must actually need adjustment (unlike the injector flow rates.) It just seems right.
So folks thought about it, experimented, make pacts with and figured out how the VE table is used. This is actually the item you'd like to modify. Keep looking at the AutoVE thing, you have lots of time to think about this, right?
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All I'm trying to do is practive how to create tables in scan tool and then use the information to make changes to the appropriate table in the tune tool (the instruction) that will give me the actual values I want to see when I log data again.
That's the essential principle of tuning, you're on the right track. Identify a desired objective, collect some data reflecting that outcome, make a change in the system, collect some new data, measure you progress toward your objective. Rinse, lather and repeat. And of course trying not to blow anything up in the process.
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I have read every single page of the scan and tune documentation as well as everything else available in EFILive and LS1Tech. Some like the AutoVE Tuning provide you with step by step instructions but it's a little too advanced for me at this point and I don't intend to run Mafless just yet.
Okay. There's no reason you couldn't play with your MAF or IFR tables. In this case, your observable is your LTFT values. You do have to do a little data massaging in order to use them (excluding weird cells) but that's no biggie. If you were to go the VE route, you'd want a WB O2 setup and your observable would be the AFR it reported.
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There is a very good tutorial for HPTuner users I found in LS1Tech that provides a step by step approach. I believe that a lot of us newbies would really benefit from having a similar guide. I appreciate your response to my question and hope that you don't mind answering what you probably consider to be dumb questions.
My gut reaction is that if it's a good tutorial it isn't actually HPTuners centric. (I.e., if it just tells you how to manipulate a tool and not why, it could be improved.) Try looking at it again and see if you can imagine going through the same steps with EFILive. That would actually be a good way to try to understand the why.
I don't know that I've helped much, or that I even answered your question. No such thing as a dumb question. I've seen folks giving you well meant advice, but I worry they are kind of pointing you toward large caliber weapons w/o much warning. Hang in there, it's a conquerable body of knowledge.
Open your last scan and select yes to replot. Look at one of your ltft maps and select a cell that's most positive and (in this case) isn't below 35kpa and has had more than 50 samples (numbers view). Now check out the dashboard and scroll through until you find the rpm and kpa matching that positive ltft value. Mark it by putting the cursor on it and slide your mouse pointer off the dashboard so that is stays on that frame. Now open the tuning application and view the VE table. Notice the grayed square? That's the cell you would modify to change the value read at that positive ltft cell. Bigger VE number will richen and lower or make more negative the ltft cell.
I agree.. don't change your MAF calibration or injector flow rate unless they've been changed. A WB makes life easier and is needed for AutoVE but you can still tune w/o one.
Guys, I haven't had a chance to look in the forum this past week but I was pleasantly surprised when I saw your replies. Your info is great! I've been a bit skeptical about some of the information thrown my way as some of it doesn't seem to add up. My gut feeling was that the MAF, being not only the first sensor, but also, the one that has to do with one of the critical elements of the a/f ratio, would be a major player in tuning the fuel trims. The VE table, as I understood, is exactly as you say, a backup in case the MAF fails, and also as a reasonableness test against the MAF readings to make sure that the MAF readings aren't out of whack. Adjusting the IFR table to correct fuel trims shouldn't be done unless you've installed larger injectors that have larger flow rates.
Now, assuming that I don't have a WB02 sensor and I want to tune for idle and transition (I think the range is idle to 3,000rpm) not WOT conditions, and the only change I've made is a cold air induction system (I have LT headers,hi-flow cats,Xpipe,Z06 Ti exhaust as well) I've got several options:
1. Adjust MAF table
2. Adjust IFR table
3. Adjust VE table (I can still do it using my LTFT values, just not for WOT) correct?
I now need to identify the same cells in whatever table I choose to tune by and using my LTFT MAP values, adjust accordingly. Except, the tune tool doesn't recommend changing the MAF table unless you've modified or changed the MAF sensor. The IFR table has no such warning and neither does the VE table.
At this point I'm a little confused because I didn't think you'd want to touch the IFR table. But, if these tables are constant values based on stock engine configuration, wouldn't it make sense that you'd be able to adjust fuel with either the MAF or IFR table? Also, I was under the impression that you don't touch the VE table unless you plan to run MAFless in which case you're speed density tuning and set the MAF fail frequecy to zero.
Sorry if I seem a bit slow understanding this stuff but since I've got all winter to learn and prepare I've got the time to take things slowly and digest information in order to understand fully the little nuances and develop a logical method to start tuning with in the Spring. Hope you guys can put up with me.
The VE table, as I understood, is exactly as you say, a backup in case the MAF fails, and also as a reasonableness test against the MAF readings to make sure that the MAF readings aren't out of whack.
I've sent you astray with my sarcasm above. Mea culpa. The VE table is used as a backup to the MAF, but not exclusively. It's role is much larger than that, hence my sarcastic comment above about "what everybody knows." Lots of people were wrong on that point. It doesn't help any that the service manuals describe the modes of operation in an oversimplified fashion. How it actually works is more complicated than that.
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Originally Posted by vetpet
At this point I'm a little confused because I didn't think you'd want to touch the IFR table.
Yes, you're correct. You don't want to change this unless you're using a different injector.
Quote:
Originally Posted by vetpet
But, if these tables are constant values based on stock engine configuration, wouldn't it make sense that you'd be able to adjust fuel with either the MAF or IFR table?
No, not really. "Be able to" and "should" are two different things. Fundamentally the MAF is just a meter with a given response characteristic. The MAF table is just how this characteristic is expressed to the PCM. All other things being equal there's no reason to change this since the response characteristic hasn't changed. Again, all other things being equal, you would be lying about the characteristics of the measuring device, not unlike using a meter stick instead of a yard stick and telling everybody that it was actually a yard stick. Same concept with the injector flow rate table. These tables describe characteristics of sensors and actuators that have *not* changed.
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Originally Posted by vetpet
Also, I was under the impression that you don't touch the VE table unless you plan to run MAFless in which case you're speed density tuning and set the MAF fail frequecy to zero.
Take another pass at this. The idea is to run w/o the MAF in order to get the VE table dialed in correctly for your physical changes. At this point you still have some choices. If you'd like to run in closed loop with a MAF as you're doing now, you can *now* go back and tune your MAF table (analogous to what you did to adjust your VE tables). This may or may not be a big adjustment as it depends on what your intake tract changes are. (The MAF sensor's response charactistic is more contextually sensitive than the injector's. Or said another way, the injector's charcteristic is better descibed as a function of it's environmental context than the MAF sensor's is.) Lots of people run this way.
People use the term SD tuning and it's a little misleading. You're using SD mode to calibrate your VE table, it's really VE tuning via SD. You may or may not choose to run permanently in SD mode. You might opt for that if you have a really big cam (mostly because of what the MAF design is lousy at dealing with, reversion in the intake path.) Another reason might be that the MAF table doesn't support the flow your engine can generate, e.g. much larger displacement. The fact that you've dialed in your VE table via SD doesn't preclude you from ultimately running w/ a MAF.
The VE table, as I understood, is exactly as you say, a backup in case the MAF fails, and also as a reasonableness test against the MAF readings to make sure that the MAF readings aren't out of whack.
I've sent you astray with my sarcasm above. Mea culpa. The VE table is used as a backup to the MAF, but not exclusively. It's role is much larger than that, hence my sarcastic comment above about "what everybody knows." Lots of people were wrong on that point. It doesn't help any that the service manuals describe the modes of operation in an oversimplified fashion. How it actually works is more complicated than that.
Quote:
Originally Posted by vetpet
At this point I'm a little confused because I didn't think you'd want to touch the IFR table.
Yes, you're correct. You don't want to change this unless you're using a different injector.
Quote:
Originally Posted by vetpet
But, if these tables are constant values based on stock engine configuration, wouldn't it make sense that you'd be able to adjust fuel with either the MAF or IFR table?
No, not really. "Be able to" and "should" are two different things. Fundamentally the MAF is just a meter with a given response characteristic. The MAF table is just how this characteristic is expressed to the PCM. All other things being equal there's no reason to change this since the response characteristic hasn't changed. Again, all other things being equal, you would be lying about the characteristics of the measuring device, not unlike using a meter stick instead of a yard stick and telling everybody that it was actually a yard stick. Same concept with the injector flow rate table. These tables describe characteristics of sensors and actuators that have *not* changed.
Quote:
Originally Posted by vetpet
Also, I was under the impression that you don't touch the VE table unless you plan to run MAFless in which case you're speed density tuning and set the MAF fail frequecy to zero.
Take another pass at this. The idea is to run w/o the MAF in order to get the VE table dialed in correctly for your physical changes. At this point you still have some choices. If you'd like to run in closed loop with a MAF as you're doing now, you can *now* go back and tune your MAF table (analogous to what you did to adjust your VE tables). This may or may not be a big adjustment as it depends on what your intake tract changes are. (The MAF sensor's response charactistic is more contextually sensitive than the injector's. Or said another way, the injector's charcteristic is better descibed as a function of it's environmental context than the MAF sensor's is.) Lots of people run this way.
People use the term SD tuning and it's a little misleading. You're using SD mode to calibrate your VE table, it's really VE tuning via SD. You may or may not choose to run permanently in SD mode. You might opt for that if you have a really big cam (mostly because of what the MAF design is lousy at dealing with, reversion in the intake path.) Another reason might be that the MAF table doesn't support the flow your engine can generate, e.g. much larger displacement. The fact that you've dialed in your VE table via SD doesn't preclude you from ultimately running w/ a MAF.
The VE table, as I understood, is exactly as you say, a backup in case the MAF fails, and also as a reasonableness test against the MAF readings to make sure that the MAF readings aren't out of whack.
I've sent you astray with my sarcasm above. Mea culpa. The VE table is used as a backup to the MAF, but not exclusively. It's role is much larger than that, hence my sarcastic comment above about "what everybody knows." Lots of people were wrong on that point. It doesn't help any that the service manuals describe the modes of operation in an oversimplified fashion. How it actually works is more complicated than that.
Quote:
Originally Posted by vetpet
At this point I'm a little confused because I didn't think you'd want to touch the IFR table.
Yes, you're correct. You don't want to change this unless you're using a different injector.
Quote:
Originally Posted by vetpet
But, if these tables are constant values based on stock engine configuration, wouldn't it make sense that you'd be able to adjust fuel with either the MAF or IFR table?
No, not really. "Be able to" and "should" are two different things. Fundamentally the MAF is just a meter with a given response characteristic. The MAF table is just how this characteristic is expressed to the PCM. All other things being equal there's no reason to change this since the response characteristic hasn't changed. Again, all other things being equal, you would be lying about the characteristics of the measuring device, not unlike using a meter stick instead of a yard stick and telling everybody that it was actually a yard stick. Same concept with the injector flow rate table. These tables describe characteristics of sensors and actuators that have *not* changed.
Quote:
Originally Posted by vetpet
Also, I was under the impression that you don't touch the VE table unless you plan to run MAFless in which case you're speed density tuning and set the MAF fail frequecy to zero.
Take another pass at this. The idea is to run w/o the MAF in order to get the VE table dialed in correctly for your physical changes. At this point you still have some choices. If you'd like to run in closed loop with a MAF as you're doing now, you can *now* go back and tune your MAF table (analogous to what you did to adjust your VE tables). This may or may not be a big adjustment as it depends on what your intake tract changes are. (The MAF sensor's response charactistic is more contextually sensitive than the injector's. Or said another way, the injector's charcteristic is better descibed as a function of it's environmental context than the MAF sensor's is.) Lots of people run this way.
People use the term SD tuning and it's a little misleading. You're using SD mode to calibrate your VE table, it's really VE tuning via SD. You may or may not choose to run permanently in SD mode. You might opt for that if you have a really big cam (mostly because of what the MAF design is lousy at dealing with, reversion in the intake path.) Another reason might be that the MAF table doesn't support the flow your engine can generate, e.g. much larger displacement. The fact that you've dialed in your VE table via SD doesn't preclude you from ultimately running w/ a MAF.
Thanks Texas. I'm sort of starting to get the picture. The weather tomorrow calls for about 60F and sunny skies so I'm going to take the car out and drive around for a while to let the PCM relearn because of the C.A.I. I installed before I parked the car. Then I'd like to log some data that hopefully has settled down from the relearn. I've seen a few different lists of PID's to log but was wondering what you would have on your list of PID's to log. This will probably be my last chance before the car gets parked permanently for our long, cold winter. One thing I will have is time.
Yup... since the IFR is constant w/ a given set of injectors and MAF once calibrated should be left alone, to primary changes are at the VE table. You want to limit other factors by forcing it into open loop so that the VE is what's used. You then use SD to tune the VE and once done, use SD to check MAF calibration or recalibrate if necessary. At this point you can just go back to using the MAF/closed loop if you want.. up to you..
These are all the cool things to look forward to!!!!!
I'd say the list of PIDs in the AutoVE.pdf doc is a good place to start. You can ignore the WB-related PIDs, both external and calculated, since you don't have a WB O2. Add in the LTFT PIDs and maybe STFT and fuel trim cell index for grins. (The default PID configuration is pretty reasonable too.) Look through the list of PIDs and see if there's something interesting that you'd like to see. You probably won't want to do any tuning from this data, but it would give you some data to look at. As much as anything else, there's some value in just getting comfortable with the basic mechanics of scanning, thinking about how you want to organize/store your data files, etc.
When I was living in Boston I had to park mine for like 5 months. I was so ready when spring (finally!) came. Dunno how you folks put up with it.
Hey Guys, thanks again for the great info. In summary,
1. I will tune the VE table using SD by disconnecting the MAF and setting the fail frequencies in the tables shown in the AutoVE tutorial.
2. I create the list of PID's I want data for and then, after logging the data, create a VE table in scan tool.
3. This calculated VE table is what I will use to replace the VE table in my tune file using cut and paste.
4. Save the new tune file and reflash my PCM.
5. Go out and log more data again.
6. Repeat the process.
7. Keep doing this until I see my LTFT's drop to zero or negative.
If there's something I haven't understood properly please let me know.
Mark it by putting the cursor on it and slide your mouse pointer off the dashboard so that is stays on that frame.
EFILive tips and tricks number 55:
Press the F2 key to prevent the mouse from moving the chart inspector (the vetical white line on the charts). You can then use the arrow keys (and CTRL+Arrow keys) to control the chart inspector.
Saves trying to slide the mouse vertically off of the charts.
Use F2 again to restore mouse control of the chart inspector.
Press the F2 key to prevent the mouse from moving the chart inspector (the vetical white line on the charts). You can then use the arrow keys (and CTRL+Arrow keys) to control the chart inspector.
Saves trying to slide the mouse vertically off of the charts.
Use F2 again to restore mouse control of the chart inspector.
Hope that helps a little
Regards
Paul
That's cool dude!!! A link to all the other tips and tricks would be great!
When you go into EFILive, look under the 'General Information' section and you will 'Tips and Tricks'. Sorry, I'm not sure how to create a link to it but you'll have no problem seeing it.
O.K. Saturday I got out to drive my car around for a while as I had installed a C.A.I. system in it a couple of weeks before and needed to give the PCM some relearn time. The rest of my mods include LT Headers, Hi-flow random tech cats, X-pipe, Z06 rear exhaust, LS6 heads and comp cams 212/218 grind.
I made up a list of PID's to log made up of from several different sources, flashed them into my flashscan and proceeded to log about 30 minutes worth of driving, different speeds, different rpms trying to hit as many cells as I could. To clarify, I didn't log in SD mode at this time.
Would any of you guys be willing to look at the MAPs I created and tell me what you think of the data? From what I see my LTFT's have gone up significantly from the last time I logged data before I installed my C.A.I. The system would seem to be having quite an effect on the fuel trims. Average values are not as good as I'd like them to be because I couldn't get at least 50 hits in some cells but at this point the data isn't as important as learning how to get the data and use it for tuning. II'll get better data come springtime.
If you can help me with this it would be appreciated. Also, since I didn't log data in SD mode, would it still be possible to tune the VE table for transition based on the LTFT limits for rpm and MAPkp? I believe the limits are 3,000rpm and 80kp.
Sure, shoot me your data, old and new, via email. I should have some time to peek at it this weekend or next week. The difference between your current and previous configuration for which you have data is just the intake, yes?
Corvette Store
A Little Help with EFILive Please.
So I have a LTFT table created in scan tool that is showing positive % for the average values in the cells logged. I need to make some adjustments so that my LTFT's will get closer to zero or slightly negative, otherwise additional fuel will be added to what is already in the PE table for WOT operation. Since LTFT's represent adjustments made due to the STFT's (02 readings, closed loop) I can't directly adjust LTFT's. My question then is, what tables in my .tun file would I be looking at changing in order to get the LTFT's where I want them to be in order to not run rich at WOT? 
It's probably even more incorrect than altering the MAF table on that point but with far fewer undesirable side effects. (The MAF signal is a key input to many other function and manipulating it for the purpose of achieving one particular objective, negative LTFTs in most cells, is missing the bigger picture.)
and figured out how the VE table is used. This is actually the item you'd like to modify. Keep looking at the AutoVE thing, you have lots of time to think about this, right?
Mea culpa. The VE table is used as a backup to the MAF, but not exclusively. It's role is much larger than that, hence my sarcastic comment above about "what everybody knows." Lots of people were wrong on that point. It doesn't help any that the service manuals describe the modes of operation in an oversimplified fashion. How it actually works is more complicated than that.
