HP Tuners Tutorials

[Gregski]

Originally Posted by MDPotter

This is exactly what I was looking for Gregski, thank you! Once I get it purchased and hooked up I will let you know if I see any red flags.

I did wire up the OBD and plugged in a cheap scanner and didn't get any codes. I guess if a tuner was just plain evil they could disable all codes, but I have some faith in them.

Especially during this moratorium you may have time to download the HP Tuners software and install it on a computer of your choice, it doesn't even have to be a laptop. It is legal and it is free. I think they call it the VCM Suite or something like that. Then download the stock tune for your vehicle from their website, you may need to create an account online to do so, if you still can't get to their repository let me know what year make and model you need and I will download it for you and email it to you. This way you can start looking at the stock configuration ahead of time.

You can also ask your tuner to send you the tune file via email so you can compare it to the stock tune file before you even buy HP Tuners

Again just trying to help cause I've been there, and it can be confusing and frustrating at first

[norcalcap]

Originally Posted by MDPotter

This is exactly what I was looking for Gregski, thank you! Once I get it purchased and hooked up I will let you know if I see any red flags.

I did wire up the OBD and plugged in a cheap scanner and didn't get any codes. I guess if a tuner was just plain evil they could disable all codes, but I have some faith in them.

I was exactly where you are a few months ago, prior to these masterful posts from Gregski!!! I received a mail-order ECM and thought my truck ran fine. I didn't have any codes and it ran well. After buying HP Tuners and following the wonderful guidance of Gregski, I realized my tune was no where near good nor safe for my truck. I had 25 LTFTs, idle was off, knock, poor idle and MAF tuning.
I never had any codes show through a scan tool, these poor parameters mentioned where realized after learning how to read and adjust the tune with HP Tuners. With the steps in this amazing post, Gregski helped tune my truck the right way, and had made an extremely noticeable difference in its performance, and as he mentions, my motor is safer (25 LTFT's is way off the charts). HP Tuners is not necessarily cheap, but I quickly learned that without it, there would have been no way I would have known how bad my tune actually was.
I really want to express my gratitude to Gregski for his dedication to this forum and specifically this post. HP Tuners was very intimidating, however, Gregski dumbed it down and made it easy for us all.

Gregski, correct me if Im wrong, but I don't think a check engine light will activate just because we have high or low fuel trims or the idle is off 50-100 rpms, etc..? I would image the computer is not seeing any problem because no one sensor is showing it to be in fault, but rather its a tuning issue, much like my truck experienced. Thus, we can not determine our motor to be running well just because we do not have a light on?

[MDPotter]

I pulled the trigger - HPTuners and credits are on the way. I did download the software a few weeks ago and have been looking around at the sample tunes and recording and can understand some of it. I really would like to gain an understanding of all of the sensors and electrical components on these engines so I can understand how they each function and help the ECM decide what to do.

[Gregski]

Originally Posted by MDPotter

I pulled the trigger - HPTuners and credits are on the way. I did download the software a few weeks ago and have been looking around at the sample tunes and recording and can understand some of it. I really would like to gain an understanding of all of the sensors and electrical components on these engines so I can understand how they each function and help the ECM decide what to do.

Awesome to hear, share some of your experiences once it arrives please, see where this tutorial fails you in your initial setup, so we can make improvements.

Also as far as the sensors, read up on O2 sensors as they are uber important, they are the ones that provide feedback that the PCM bases it's adjustments on. Understand the difference between narrowband and wideband oxygen sensors. Learn and share if you can clean them, if you can extend the cables, what the different deviations between brands are and their impact on OEM application, etc.

Then I would read about the MAF Mass Airflow sensor and it's role in the big picture, probably the most misunderstood sensor there is.

Follow that up with the MAP Manifold Absolute Pressure sensor and this whole Speed Density thing.

[MDPotter]

So my HPTuners showed up yesterday and I couldn't wait to start using it so I plugged it into my daily (bone stock Gen V 5.3) and nerded out for awhile (my fiancee's words). I went for a short drive and recorded some data and took two screenshots - cruising and WOT - so I could see the difference between the two. I'll build a configuration tonight so I can plug into my 68 tomorrow and see what's going on with it.

I noticed that at cruise my STFT's and LTFT's were all within 4% so that goes to show how well GM has these tuned. It was also cool to see it go into open loop at WOT and to see what all of the sensors do.

What I don't understand is all of the throttle position channels and why they all read differently. At WOT, only 1 of 4 read as 100%?

And do these Gen V's run off variable fuel pressure? It's my understanding that Gen III's and IV's require a constant 58 psi, but the reading on my Gen V was anywhere from 40 to 70.

And why don't I have a reading for injector duty cycle? Wouldn't this be useful in tuning to know the limits of my injectors?

[Gregski]

Originally Posted by MDPotter

So my HPTuners showed up yesterday and I couldn't wait to start using it so I plugged it into my daily (bone stock Gen V 5.3) and nerded out for awhile (my fiancee's words).

[Gregski]

Originally Posted by MDPotter

And do these Gen V's run off variable fuel pressure? It's my understanding that Gen III's and IV's require a constant 58 psi, but the reading on my Gen V was anywhere from 40 to 70.

I'm sorry to dissect your post, but there is so much good data in it that I want to address it point by point, you did awesome!

Honestly I know nothing about the Gen Vs, that will be a Tutorial written by you, ha ha.

As far as the Gen III's it is my understanding that they came in two flavoures: fixed and referenced

These are commonly referred to as returnless style fuel pressure system aka one fuel line (think Corvettes and Camaros with true 5.7L LS1/LS6 engines) and return style aka two fuel lines (these would be our truck engines 4.8L LR4, 5.3L LM7, and 6.0L)

These setups allow one to flow constant pressure at all times while the other is vacuum pressure regulated.

here is a sample 2000 Camaro Injector Flow Rate vs KPA table

[Gregski]

more on Fuel Injectors

and here is that same table from a 2001 GMC Sierra truck with a return two fuel line system with a vacuum pressure regulator, notice how the flow rate is the same across the entire table

[MDPotter]

Gregski, if at any point I'm cluttering your thread let me know.

I was successful in connecting to my 68 and recorded a log and also downloaded the tune. From my very limited knowledge of tuning, it appears to be running pretty well. I created a configuration from gregski's posts.

Some observations from the logging:
-I noticed that the MAF, MAP, and Speedo gauges weren't showing anything. I found out that if I added those channels that the gauges would provide a reading. I got the MAF and Speedo to work, but still haven't found the right channel for the MAP.
-At idle, STFT's were between 0 and -3.
-At cruise, STFT's were between 0 and -10.
-Barometric pressure reading was about 5 inHG lower than the weather app on my phone shows. But the same thing on my 2016 and my fiancee's Dodge Nitro. Why is that?
-There was a few minutes during the drive that STFT's were at 0, is that normal?

Looking at the tune:
-Is shown as the correct donor vehicle, just a different VIN
-Power enrichment appears to be enabled
-Segment swap for 4L80E
-Speed limiter disabled
-A lot of DTC's are disabled, much more than gregski indicated in earlier posts. Such as fuel trims, PCM speed output, MAP sensor, IAT sensor, O2 sensors (bank 1 & 2, sensor 1), MIL control circuit, TPS, all "U" codes. I am thinking about enabling everything except the DTC's that gregski noted. Thoughts?

Idle Snapshot:


Cruise Snapshot (O STFT's):


Cruise Snapshot (moving STFT's):


Primary VE Table:


Again, I am in the very early learning stages of tuning, but it looks like I should give the tuner some credit?

[Gregski]

Originally Posted by MDPotter

Gregski, if at any point I'm cluttering your thread let me know.

Yeah, stop cluttering "my" thread! Are you kidding me, this is great, I actually appreciate you doing this as it helps us test the tutorial if you will. I'm going to address some of your questions in separate replies.

[Gregski]

Originally Posted by MDPotter

Some observations from the logging:
-I noticed that the MAF, MAP, and Speedo gauges weren't showing anything. I found out that if I added those channels that the gauges would provide a reading. I got the MAF and Speedo to work, but still haven't found the right channel for the MAP.

Sorry it took me a while to get back to you mate, please try the:

Intake Manifold Absolute Pressure (SAE) channel

[Gregski]

Originally Posted by MDPotter

-Barometric pressure reading was about 5 inHG lower than the weather app on my phone shows. But the same thing on my 2016 and my fiancee's Dodge Nitro. Why is that?

LOL, Location: Western Colorado ie Elevation, but mad props to you for doing the stare and compare with another vehicle, well done mate!

[MDPotter]

Originally Posted by Gregski

LOL, Location: Western Colorado ie Elevation, but mad props to you for doing the stare and compare with another vehicle, well done mate!

That makes sense and that's what I expected. Apparently the reading from The Weather Channel isn't accurate. Not a big deal, just something I noticed. Just another reason not to believe the weather man.

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

Well, it's been a while, might as well get back into it. I honestly don't recall where we left off so forgive any overlap as we dust off the cobwebs together.

Let's free up some oomph in our trucks. For those of you who have have tuned with a screw driver before ie tinkered with a carburetor (pronounced: "a controlled fuel leak") you are probably familiar with an accelerator pump and those of you who know what a Double Pumper is get double bragging rights! ha ha

basically when you are just cruising along and you step on the gas pedal, it takes a while for the system to react, since air travels faster than fluid, the gasoline needs a little extra kick in the pants so that we don't lean out and have to fix things with our wallet.

So in the carb world this rubber diaphragm spring plunger thingie would literally spray extra fuel into the throat of the carb like a Windex squirt bottle.

Now in the HP Tuner world with EFI the similar system is called Power Enrichment and it just so happens that it is crippled on most if not all truck/SUV Third Gen LSes.

Coming up next we will take a closer look how our engines / PCMs come configured from the General, and how we can "fix" that and get that feel by the seat of our pants acceleration.

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

We find the Power Enrichment settings in two places in the VCM Editor. The first place is under Engine \ Fuel \ Power Enrich tab and then the Delay section

Here we see how a Tahoe engine was configured:

RPM 5,000
Delay 0.8

This basically means do not kick in Power Enrichment unless this Soccer Mom holds the RPM at or above 5,000 for more than .8 seconds, (basically that will never happen) so essentially PE is disabled on this SUV

Note: your default factory settings may vary slightly, the RPM may be 5,500 and the Delay may actually already be 0

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

we need to zero out both fields so they look like this:

this eliminates any delay and PE will kick in provided some of the other conditions are met but at least the RPMs won't prevent PE from kicking in

we will address the other influencers next

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

Throttle position is the second thing that effects or prevents PE from kicking in

We find these settings on the same page under Engine \ Fuel \ Power Enrich tab and then the Throttle section under both the Hot and Cold buttons

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

here is what the default Hot and Cold tables look like, they basically say when the throttle is at 90% at the above listed RPMs only then kick in Power Enrichment, so again pretty much never when for example you try to pass somebody on the freeway, unless you mash the gas pedal

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

Alright, how do we fix this? Well there's three ways to go about it if not more, and it's a bit more of an art than science, in other words do it to your liking and see how your truck responds.

So here is one way to do it, start by cutting that number approximately in half, (for both the Hot and Cold tables) so instead of having the PE come in at 90% throttle set it so say 50% like so.

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

Another way to approach this would be to say well I don't want all that extra fuel at the lower RPMs so maybe don't kick in PE until 2,000 RPM or what ever RPM you feel is right for you, like so:

And once again make sure you update both tables, the Cold one especially as the PCM hardly if ever will get to the temp to use the Hot one

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

some of you may have heard the old adage "good composers borrow, great composers steal" which brings us to the third way of adjusting those Hot and Cold PE tables

we can look how GM did it from the factory in the true LS1 sport cars such as the 2001 Camaro, now keep in mind that engine is a 5.7L and has some different components on it, but here's how them cars are set up as a reference, note how their Hot and Cold tables are actually different!

Top Tip: You can look at all the stock tune files from the HPTuners.com website. First you need to download their Software for FREE, it is completely allowed and legal and then you can download stock tune files that people have uploaded from their vehicles to their website for others to use.

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

well so far we've told our engine computers to turn on Power Enrichment and when to do it, but what is it actually going to do?

so to wrap up Power Enrichment we must discuss the Power Enrichment EQ Ratio table, what the hewk is it?

first EQ stands for Equivalence Ratio, and we find it on the same page under Engine \ Fuel \ Power Enrich tab and then the Power Enrichment section under the EQ Ratio (Gas) button

[Gregski]

Part IX - Enable Power Enrichment aka Accelerator Pump / Secondaries

this table tells the computer what the air fuel ratio mixture needs to be or needs to equal at a certain RPM

so the computer doesn't just go hey the guy pressed the gas pedal more than 50% and the RPMs are at 4000 so shoot some more gasoline in the engine, instead it says at 4000 RPM we need to shoot precisely this set amount of fuel to make the gasoline mixture equal stoich (14.681) divided by 1.246

so that equals an AFR of 11.78 in essence richening the air fuel ratio

(remember about 13.50 is neutral or cruising AFR, as an example anything lower to like 11.50 is rich which means more power, anything above that is lean up to for example 15.50 which is fine for say coasting on the highway)

I'm an old timer so I speak in AFR and not in Lambda like all the cool kids do now

so we can play with the numbers in this table a little bit, since simply going richer does not mean more power, there is a sweet spot, what I like to do is see if coming in richer sooner has a positive effect in other words do you get more power at lower RPMs, then I do the opposite and see if I can lean out the fuel a little at the higher RPMs if there is no more power gains up high, or you can shift that Ratio to the left a few cells or shift it to the right a few cells type of thing

[ls1nova71]

Hey Gregski, I'm really glad you are back to continuing this thread, it's very helpful. I've read it several times, just wish I could remember it all! It seems if I don't use this information for a while, which isn't all that long to be honest, I just loose everything I had read and learned. Not sure if that says more about HPTuners or me! LOL But keep it up, its a great source of info for the beginner.

[Gregski]

Originally Posted by ls1nova71

Hey Gregski, I'm really glad you are back to continuing this thread, it's very helpful. I've read it several times, just wish I could remember it all! It seems if I don't use this information for a while, which isn't all that long to be honest, I just loose everything I had read and learned. Not sure if that says more about HPTuners or me! LOL But keep it up, its a great source of info for the beginner.

thnak you so much, honestly, ditto, lol and I am glad you are not tinkering with it daily, that's the whole point, you tune it then you drive it, there are just so many nooks and cranies but that's no different than forgetting what size jets you put on your Holley last time you re jetted it back in the day, even if you swore you'll remember 72 since that's the year you were born, ha ha, just sayin'