Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
So first we look at the Engine Coolant Temp ok it's 57* F, so here are our thoughts:
looking below this Channel, at the next one Fuel System #1 Status says OL - Not Ready, our thoughts:
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Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
looking at our next Channel, Barometric Pressure, our thought are
for now, the channel below Manifold Vacuum we just want to make sure it has a value, and it is as close to zero as possible |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
now you may notice that the Barometric Pressure Channel reports in PSI instead of inHg (Inches of Mercury) hey that's Physics for you (seven different ways to say the same thing), and yes this is one of the things that you will do battle with in HP Tuners quite often, making sure you are comparing Apples to Apples and not Apples to Oranges type of thing, so simply right click that Channel select Units and choose the format you desire |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
the Intake Air Temp channel is next, and this one can get skewed like in my case cause my truck has been parked in the shade all day so it shows a temp a few degrees below my iPhone Weather app So you knowing this, maybe use a local indoor outdoor thermometer barometer temp gauge thingie to get a better reading of the local air temp, or park your truck in a different spot, you get the idea |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
Mass Airflow Sensor shows a perfect ready to go Key On engine not running reading of 0 hertz |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
for the Engine RPM we just expect to see a value of 0 to prove the tach signal is coming through |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
same goes for the Timing Advance channel we don't expect to see anything above 0 with just the key on and the engine not running, but seeing a zero is a good sign means we picked the right PID (Parameter ID) and there is a signal on the line |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
and both O2 Voltage sensors are perfectly in the middle of .100 and .900 volts with the key on, and the vehicle not running |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Key On - Vehicle Not Running - Systems Check
now I would be lying if I told you I wasn't genuinely concerned about the low Control Module Voltage even if this is key on engine not running, something may be draining my battery here and low battery voltage can brick your PCM when you are flashing it |
Re: HP Tuners Tutorials - Chapter 1 - Logging
OK, let's use our Basic Channel config to evaluate the second of the three vehicle conditions:
1. Key on - vehicle not running 2. Vehicle Running - Open Loop 3. Vehicle Running - Closed Loop |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running Open Loop - Systems Check
So now that the truck is running we see the presence of Manifold Vacuum, we observe that our value is now well above 0 We see a similar result for the Mass Airflow Sensor Obviously Engine RPM has climbed as well, though we don't know if it's where it should be yet, but that's ok for now, we are learning likewise we have a Timing Advance that is greater than zero |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running Open Loop - Systems Check
now we see an interesting condition regarding our two O2 Sensors Voltage, it appears it went from middle of the road around .450 with the key on to above .900 with the truck running and warming up, later we will learn that this reflects a rich condition, but since the rig is warming up this is acceptable (think choke on) |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running Open Loop - Systems Check
and finally the Control Module Voltage looks much better, with the engine running, it is above 14 volts |
Re: HP Tuners Tutorials - Chapter 1 - Logging
Lastly, let's use our Basic Channel config to point out the channel value differences in the final of the three vehicle conditions:
1. Key on - vehicle not running 2. Vehicle Running - Open Loop 3. Vehicle Running - Closed Loop |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running - Closed Loop
I hope you stuck it out this far, as things began to get interesting. I pointed out earlier the importance of the Engine Coolant Temp and here is the first example of its cause and effect. When the temperature reaches 131*F notice what happens in the Fuel System #1 Status channel below it? The status changes from OL - Not Ready to CL - Normal CL meaning Closed Loop now. |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running - Closed Loop
lets take a deeper dive and see what exactly caused that switch from Open Loop to Closed Loop We know all of our configuration settings come from the VCM Editor so we fire it up and go to Engine \ Fuel \ Oxygen Sensors and look under the Closed Loop Enable heading where we find the ECT vs. IAT table (highlighted in pink for easier spotability that's all) We put our mouse over it, and glance at the bottom of the screen where we find the Context Clues, which read: This table sets the coolant temperature required to enable Closed Loop in relation to inlet air temperature (IAT). We open up that little guy, and it's not really a table as it is a list, but so be it. We quickly and easily see that once the ECT (Engine Coolant Temp) hits 131 (the big green bar) and our Intake Air Temp is above at least 50* we will turn on Closed Loop. Cool beans, so things are working as they should and now we know why. Don't take this for granted, someday you may be troubleshooting an issue caused by your PCM never entering Closed Loop mode, so just keep that in mind please. |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running - Closed Loop
further down the list allow me to point out another cause and effect of you guessed it the Engine Coolant Temp The engine is a little warmer now, it has reached 154* F, it's time to cause another thing to happen... Note the drop in Engine RPM to approximately 550 |
Re: HP Tuners Tutorials - Chapter 1 - Logging
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Vehicle Running - Closed Loop
once again lets take a deeper dive and see what exactly caused the RPM to settle in at 550 so back to the VCM Editor we go (you will find this is the common Tango you will be performing whilst dueling HP Tuners ie. going to and fro from VCM Scanner to VCM Editor and back) Engine \ Idle \ RPM is where we find the Base Setpoint heading and the Base table lurks under it with our mouse hovering over it, we glance below to see: This table controls the desired idle RPM vs. Engine Coolant Temperature. This being an actual table and not a simple list, allow me to explain how I read it. There are four conditions:
So in our case in Park with the Air Conditioning off (deleted actually) and with the Engine Coolant Temp at 154* F we should be idling at 550, and we are. High fives all the way around! |
Re: HP Tuners Tutorials - Chapter 1 - Logging
This concludes Chapter 1 - Logging
I hope I whetted your appetite for doing some tuning on your own or at least exploring the VCM Scanner. If you have some channels you like to use to do your initial system checks that I have omitted please let us know, we're all here to learn. |
Re: HP Tuners Tutorials
I have been following along the entire time and have learned a lot. Thanks again for doing this.
Jimmy |
Re: HP Tuners Tutorials - Long Term Fuel Trims Short Term Fuel Trims
Long Term Fuel Trims and Short Term Fuel Trims, yeah we all heard the terms or the four letter acronyms LTFTs and STFTs, but what are they really?
A long time ago a teacher I had would tell us to substitute a word for a term we did not know instead of defining it for us, and it worked, so let's try this, any time you see the word Trims substitute it with the word "Changes" So Long Term Fuel Trims become Long Term Fuel Changes and Short Term Fuel Trims become Short Term Fuel Changes You could also use the word Adjustments or modifications, or what ever you come up with that works for you. Now some may find the following analogy or example silly, but I think it works as we all can relate to it, plus everyone enjoys a good short story. So it's the first day of Winter and you have to get dressed for school. So you put on the usual a T shirt and some jeans (socks, shoes and underwear is assumed) so in other words your VE outfit your Volumetric Efficiency or standard outfit. On Monday you step outside and start walking to school, soon you find it's colder than you expected but you press on. Tuesday same thing you throw on a different T shirt but still just a T shirt and a pair of jeans and you head out, freezing your butt off all the way there. On Wednesday you step outside in your T shirt and a pair of jeans and you say screw this I am making an adjustment and you grab a jacket and put it on and zip it up to the top (there you just made a Long Term Fuel Trim) from here on out you will bring a jacket until the weather will get too hot again. You walk to school wearing that jacket but once you get to class you are sweating, you think nothing of it. Thursday you head outside in a T shirt, jeans, and jacket of course, but half way there you think I'm getting hot, I should unzip my jacket (A Short Term Fuel Trim change) you get to school and you are no longer sweaty like the day before, you think I think I got this Friday morning you put on your T shirt, jeans, and a jacket but you don't zip it up today, nope the Short Term Fuel Trim has now become part of the Long Term Fuel Trim baseline if you will now if you start walking to school and it gets too cold, starts raining or snowing, by all means you have the freedom to zip up your jacket again, making yet another Short Term Fuel Trim adjustment/change |
Re: HP Tuners Tutorials
Just wanted to clarify something that had me tripped up for a while and may help you. The objective is to get us thinking, in a non biased way as realists.
Do you need a Wideband Oxygen Sensor AFR Gauge to tune? The short answer is no. The better answer is, it depends. I bring this up for two reasons: 1. We need to understand what is controlling what as the vehicle goes through it's operational phases in order to determine for ourselves which tuning method to use and why.Let me preface what I am about to say and tell you that I am not anti Wideband gauges I use them I run them in my vehicles, however there are Pros and Cons to using both methods. Tuning Using the Stock Narrow Band Oxygen Sensors PROSTuning Using Wideband Oxygen Sensor(s) AFR Gauge PROS... and please don't get me started on Mail Order PCM tunes!!! hee hee RECOMMENDATION: In the end I like to use both methods, aka the belt and suspenders solution, that way you can cross check your results and perhaps account for any discrepencies. |
Re: HP Tuners Tutorials
I just received my HP tuner equipment in the mail last night. I will go back review the thread & make wire harness to power up my ECM so I can work on it on the bench while it’s raining. Until I get my engine harness reworked and my truck is ready.
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Re: HP Tuners Tutorials
Quote:
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Re: HP Tuners Tutorials
Yes it is
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Re: HP Tuners Tutorials
Nice description of fuel trims! I wish I would have had someone put it in those terms before I started playing around with tuner pro and TBI.
Also a great way of summarizing the use of NB vs WB. I did my initial TBI tunes on the Caddy in open loop with the wideband, and now do my small tweaks off BLM (fuel trim) values, with the wideband just as a verification since it does respond faster. It is helpful for quicker throttle transitions, maybe the LS pcm reads/responds fast enough. TBI sure doesn’t.:lol: |
Re: HP Tuners Tutorials
Quote:
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Re: HP Tuners Tutorials - MAF Calibration
MAF Scaling - Calibration
Arguably the Mass Air Flow sensor aka the MAF is the most important sensor on our Gen 3 engines (when it comes to fueling, the Temp Sensor is King overall, ha ha). We all have heard that the engine is nothing more than a sophisticated air pump. Buying into that analogy we begin to understand how the magic of mixing the the right amount of air and fuel at the right amount of (spark) time happens. Fuel injected engines can rely on one of two air delivery methods, using the MAF sensor or using the MAP sensor (pronounced: Speed Density). To make things even more complicated, GM decided to use both, yes at the same time. Before we get to that, let's highlight the differences. The MAF method ~MEASURES~ the actual amount of air going into the engine at that given moment in time. Now it seems perfect and makes you wonder why the MAF sometimes gets a bad rap, I mean who wouldn't want to know exactly precisely how much air is entering the system, right? Well the MAF has a few drawbacks, first, it don't know if the air is coming or going, so it measures air in either direction as it passes through it's super duper uber sensitive wire sensor that measures air mass based on how hot or cold that wire needs to be (blah blah blah). So if for some reason a wild cam pushes some back pressure air backwards in the intake manifold guess what? the MAF measures that as if it was going in. The second issue the MAF has is with TRANSIENT (pronounced quick) throttle changes, so you slam on the gas pedal, the MAF goes WTF, same goes for when you let off the throttle pedal right quick, the MAF can't exactly keep up. Thirdly, the MAF lives about a foot and a half away from the throttle body on a cold air intake housing or some sort of plastic tube, well that's where it measure the air, so what if there is a tiny hole or leak in that housing after the MAF, ie past it, the MAF don't know anything about it, so who or what accounts for that additional air, (pronounced: vacuum leak, ha ha) Enter the MAP. If the MAF is the Accountant in the bunch, the Manifold Absolute Pressure sensor is the Mathematician if you will. Instead of measuring the air, the MAP ~CALCULATES~ it. Well technically the PCM does the heavy lifting but the MAP feeds some crucial information into that super duper complicated formula to come up with something called Cylinder Airmass. (Google: Ideal Gas Law, or don't ha ha). Cylinder Airmass as the name implies is the calculated amount of air that arrives at each individual cylinder, not the total eight cylinders at the same time. This use of the MAP is called Speed Density, you may have heard of guys running only in Speed Density mode, and that's a topic for an entire separate discussion, it just means they disabled their MAF and don't rely on it at all (not smart for daily drivers as it castrates what makes the LSx engines such good engines). The MAP / Speed Density which uses the Volumetric Efficiency aka VE table method also has its pros and cons, such as factoring in air temp, humidity, etc. all which effects the final computation, that's why GM decided to use both. So majority of the time our Gen 3 engines are relying on the MAF, but when we transition too abruptly with the gas pedal either on or off the PCM takes a peak at the VE table ie Speed Density to keep the MAF honest. Also according to the factory settings, above 4,000 RPM we only rely on the MAF sensor and no longer use both methods (take that Speed Density only guys, joking) as the air rushing in is more stable at that point and the readings are more accurate. Now we are gathered here today because we most likely done did an LS Swap, in which case we altered the intake track (ditched the fugly OE air box, changed the air filter, changed to a cold air intake, changed the location of the MAF, etc.) The precise calibration that the GM engineers/technicians have done at the factory has gone out the window. This is why we start by tuning\calibrating the MAF. It sounds intimidating at first, but don't be skierd. |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
In order to tune or calibrate the MAF sensor the first thing we want to do is take our last tune file I think we left off on a file called 14 - Turn Off Cat Protection.hpt open it in VCM Editor and turn right around and save it as something called 00 - MAF Calibration - Initial.hpt yes this file will contain exactly precisely what the 14 - Turn Off Cat Protection.hpt file has in it, but it will be our fall back with a clear name of what it is. As you will see below in the second screen shot, I actually geek out and create a separate directory for each component that I am going to tune, you can see below I created a Folder structure for MAF Calibration containing its own logs, channels, graphs, tunes, etc., but hey, you do you |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
ok, now without making any changes in the VCM Editor, simply save this file again, yet with another name, call it something like 01 - MAF Calibration - Setup.hpt and bear with me, this naming renaming files thing may seem a bit odd, but once you rinse, lather, and repeat this process a few times it will begin to sink in, it's basically that an ounce of prevention is worth a pound of cure mentality so now in my MAF Calibration folder I show two files, the first is what I will fall back to if I jack things up too much, and the second file is where i will make my special changes to in order to setup the PCM for MAF calibration, this configuration is temporary and only for the time spent calibrating the MAF, you do not want to drive around for days, weeks, months in this temporary condition |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
MAF Scaling - Calibration
You can calibrate the MAF in two ways, using either the stock narrow band oxygen sensors or using an aftermarket wideband oxygen sensor ie AFR gauge. Option 1. Factory Narrowband Oxygen Sensor Method To make things even more complicated, in this method you have three further choices:Option 2. Aftermarket Wideband Oxygen Sensor Method PROS you can tune the entire operational spectrum with this method, Idle, Cruise, and Wide Open Throttle (WOT) so both the Closed and Open Loop.Because this is a basic tutorial intended to wet your appetite for tuning we will be using the factory narrow band Option 1 above relying on both the LTFT+STFT special math function for the win! Nothing stops you from going at it a second time once you have a Wideband and confirming this tune and building upon it by also tuning WOT. |
Re: HP Tuners Tutorials -MAF Scaling - Calibration
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MAF Scaling - Calibration
We can take a look at the current existing MAF Calibration under Engine \ Airflow \ General tab \ MAF Calibration section in the Airflow vs. Frequency table |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
Using the Horizontal Split menu item (red arrow below) I strongly recommend you simply take a look at what the initial exponential(?) graph looks like first, if you have a virgin factory configuration it should look like a nice quarter pipe for those of you who were skaters, ha ha, no spikes, peaks, divots, valleys, just nice smooth transition |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
if someone already took liberties with your configuration and mocked it all up, here you can see before you even go making any changes yourself how bad the graph really looks you are hoping that when you are done, yours will not look like this, ha ha, if it does, you did something wrong, or more likely you got some bad data |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
With a mental picture of our current MAF graph we are ready to put our PCM in MAF Calibration mode. In order to do that we must disable Speed Density, in other words we don't want the MAP sensor and the VE table assisting or correcting how much air is flowing into the engine, we want to solely rely on the MAF so that we can calibrate it. To achieve this isolation we go to Engine \ Airflow \ Dynamic tab \ Dynamic Airflow section \ and set the High RPM Disable to 200 rpm now if we glance on the help section below we can read a rather confusing description: "[ECM] 3003 - Dynamic Airflow High RPM Disable: Above this RPM use filtered MAF airmass for airmass prediction calculations."yet watch what happens when I only add one word: "[ECM] 3003 - Dynamic Airflow High RPM Disable: |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
MAF Scaling - Calibration
That's it, that's all you have to do in the VCM Editor to start calibrating your MAF, the rest of the magic happens in the VCM Scanner. What about Power Enrichment won't that skew our data? Technically we have not enabled Power Enrichment yet, as it comes crippled from the factory on these trucks, for example mine would not kick in until I was above 5,500 RPM (ridiculous I know) on some 6.0L it takes that plus being above 5,500 RPM for like 30 or 60 seconds. If you enabled your Power Enrichment like I have you can avoid it interfering in other ways, for example, don't go above 5,500 RPM while calibrating your MAF, ha ha, or stay below what ever RPM and or throttle position you set the Power Enrichment to kick in at, so you can take care of it by the way you drive (FYI factory wants you to be above 90% throttle for Power Enrichment to kick in), you can also filter out Power Enrichment mode in the VCM Scanner when you are logging the data, we will be taking this approach. Also technically WOT puts you in Open Loop and we can't tune that with the narrowband O2 sensors anyway, it's just that slight early transition from the end of cruise and into the early start of Power Enrichment that gets skewed. Another obstacle for us can be DFCO aka Deceleration Fuel Cutoff, this is a feature where when you are cruising and you let off the gas pedal really quickly, the computer shuts off fuel delivery to the engine (why waste fuel right) well this makes the O2 sensors read super lean for a split second and those readings can jack up our MAF calibration, again you can avoid this by not lifting completely off the throttle during MAF calibration, and this too can be filtered out in the VCM Scanner during data logging. I like the belt and suspenders method, where we try to do both, drive accordingly (no sudden throttle changes, just smooth cruising through as much of the RPM range and load as we can get) during MAF calibration driving and also I like to rely on the filters. |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
After we made that one simple change in the VCM Editor to disable Speed Density for the duration of our MAF calibration, now we need to add some Channels in the VCM Scanner. First I would like to show you the bare minimum of channels that it takes, we basically need two things: 1. the Mass Airflow Sensor frequency 2. the Short and Long Term Fuel trims (all four of these channels) that's it with these five channels we can tune the MAF, however later I will tell you why you may want to add some more channels just so you have some perspective as in how fast were you going at the time, what was the engine RPM, what was your intake manifold pressure like, what position your throttle was at, were you in Open or Closed loop, etc. just some nice to haves. |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
after we have our Channels now comes the scary part now we need to setup something called a Histogram (pronounced: "graph") we also do this in the VCM Scanner, and it will look like this (right side of the screen) |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
and here's how you build that graph Label: you can call it what ever you want "MAF Tuning" or "LTFT+STFT MAF" whatever Parameter: this is key and you want to select the LTFT + STFT [Math] function View: make sure it's set to Average Decimals: set it to 2 Function: we will talk about this later, this is a bit advanced Cell Hits Required: make it 20 or 50 as long as it is more than 1 Shading High Value: 20 or 25 red usually to show lean Low Value: -20 or -25 green usually to show rich Column Axis Parameter: select the Mass Airflow Frequency [Sensor] Values: cut and paste these from the MAF Calibration section Airflow vs Frequency table in the VCM Editor by right clicking anywhere in that table and choosing Column Axis / Copy Labels |
Re: HP Tuners Tutorials - MAF Scaling - Calibration
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MAF Scaling - Calibration
Once we have the Channels and the Graph in the VCM Scanner configured we need to go back to the VCM Editor and write the 01 - MAF Calibration - Setup.hpt file to the PCM. We should all be familiar with how the write aka Flashing works by now. Then once the truck is warmed up, I like to switch to the VCM Scanner on my laptop and drive out to a place with no oncoming traffic and no stop lights, and start my calibration drive. I start driving and then press the start recording on my laptop. Then I just drive around without going into WOT. You do not need to stare at your laptop while driving. When done maybe 10 or 20 minutes later, stop the scan before you stop the drive, then come to a complete stop somewhere safe and save your log so that your laptop battery does not die. Top Tip: if you start seeing numbers in the double digits like 13.60, 14.50, or 15.30 then you can increase your MAF calibration by something like 10%. You would do this by going to the MAF Calibration table in the VCM Editor selecting the entire table and then type 1.10 in the box on the menu and hit X to multiply. I make this suggestion right off the bat because it is dangerous to be that lean. Remember it is better to be a little rich like -2% than lean, and double digits lean is bad. So don't over think it, if your numbers are 17.20, 18.90, or 19.20 then increase your fueling by 15% so multiply the entire table by 1.15, kapish, get out of the red zone ASAP. |
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