HP Tuners Tutorials

[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.

[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