So a while ago, I was talking to a guy on this forum. He told me that the mass airflow sensor and the hypertech tuner I had may or may not have been really helping me, because they don't cater to the specific needs of an individual truck. He said that I'd be better off de-screening the stock mass air, putting it back in, ripping out the hypertech tuning, and gettin a program like HP Tuners to dial 'er in right. Excellent. That's what I've done. Everything, that is, except for the "dial 'er in right" part...

OH MY GOD THIS SOFTWARE IS CRAZY!!! Look, I am a car guy, and I am a computer guy - both to a pretty extreme degree. But this sh*t is so complex that I'm at a loss! I checked in the help file in the "How to get started" section, and all it said was "Coming soon..."
*sigh*
So I downloaded my stock program and I've been looking through it - heck, I even scanned in the hypertech program just so I could potentially see what they're doing to make things hum. I just feel like I'm not getting anywhere with it, none the less.

I'm sure there's a lot of seasoned tuning veterans out there, and I guess what I'm asking is - how the heck does an intelligent computer/car guy get started with this EXTREMELY convoluted program?!?

Thanks!

 

read read read.... not sure what else you can do other than that... the HPT software is layed out pretty logically and is easy to use... guess the thing to keep in mind is you don't need EVERY table.....

The histograms are your friends... they make it so easy to understand what the various tables are doing (like the spark histogram... or look at the knock histogram and you can see where you're running too much timing in your spark tables)

Best bet is to read through the help file (it's very informative.. especially in version 2.0 which includes some how-tos ... read the table descriptions for all the tables.. you'll start to see where things interact and what tables are critical to driveability and which are critical to WOT) ... read the stickies here... when you have a question on how to do something search here first and if you don't find anything post the question up... there are tons of us here that can answer it....

Few things to get you started that you want to research:

Long Term Fuel Trims (LTFT)
Short Term Fuel Trims (STFT)
MAF Table
VE (Volumetric efficiency table) -- this is one of the most important tables
PE (Power Enrichment) -- this is critical for WOT
Spark tables (higha nd low) -- critical for your timing advance (combined w/the adder tables like IAT (incoming air temp) vs Spark (so it can add ore remove timing from the base table based on the IAT value)

don't worry about every single table... just look at the tables that concern the tuning issue you're having (You must know what yoiu need to tune right? part throttle, WOT, etc...)

 

Like Horist said, you must read! Read the help file and read this section for about a month.

If you think HP Tuners is hard to learn, your lucky you didn't buy LS1 Edit. There is no help file and no support from them. They haven't had any new updates in well over a year!

Bill

 

Actually, no, I'm not really sure what I need to tune... I mean, I've got a clue, but I've also got a clue abotu how a 4L60E works, and you won't find me tearing mine apart any time soon... Like I said, I looked at the hypertech tune and compared it to the stock tune to try to get some ideas, but I feel like I might f*ck something up if I go in there *****-nilly just changing parameters...

Also, I did a log of the sensor activity and whatnot, and both O2 sensor graphs were ALL over the place - they didn't stabilize until about 3000rpm, then as soon as I drop back below 3000, they start going haywire again. By haywire, I mean that they appear to be creating a sinewave on the graph with a period of about 1 second that fluctuate from 0mv to 1000mv. Any thoughts on that?

And Horist, it just so happened that I looked at the "credits" for the program when I first installed it and was reviewing the help file... Are you the beta tester Horist of which they speak?

Thanks,
Zac

 

Yes, the o2 sensors are supposed to fluctuate around 500 mv. If they do not constantly switch voltage, the pcm will throw an error code. The reason they stabilize at higher rpm is that you enter power enrich mode, which is too rich for them to accurately read, therefore they just go to around 900 mv and stay there. There is actually a lot more to it than that, but that is a generalized idea. HPT V2.0 has a nice file compare function which allows you to look at the changes between something like your hypertech file and your stock file. Just remember to keep your stock file in case you totally **** something up while experimenting. Also keep in mind that your odds of blowing a motor N/A are very low compared to F/I, so don't be afraid to experiment.

 

You get used to the software after a while. I know it like the back of my hand...hey where did that mole on my hand come from....

 

Indeed that's me


When I say you must know what you need to tune I mean in a general sense... like do you have idle issues right now? or are you just looking for Full Throttle /WOT tuning? are you looking to change shift points?

Post up what you want to accomplish or what you think you'd like to do (basically the main areas of tuning are driveability/part throttle. WOT performance, changing SES light status/display options, and for an auto trans changing shift points)

Do you have a dyno chart for the car? That can come in handy also in determining what you would want to change....


As mentioned, the O2 sensors are supposed to look "haywire" ... they switch high low high low constantly (since the PCM tries to maintain an average of 14.7:1 or so) , so the PCM will add fuel then pull fuel and back and forth, based on the O2 readings. When you enter Power Enrich (>55% throttle I believe) then you go into what's called "Open Loop" ... Open Loop uses only the primary sensors... IAT, MAF, TPS, MAP, ECT, Knock to determine your fueling and timing needs (actually open loop only affects fueling), in open loop your O2 sensors are ignored and internal tables (VE and PE are large in this for WOT) are used to calculate the necessary fuel

When you first start the car up you're in open loop, but then when it warms it switches to closed loop (which is when the O2s start switching high low high low) ... closed loop uses the sensor above, but also uses the O2 sensors to determing fueling needs (the O2s cause the Short Term fuel trims to update... then the short term fuel trims in turn cause the Long term fuel trims to update, this information is used by the PCM to adjust fueling for regular driving... it's kind of a fudge factor to make up for innacurate air metering/measurements or incorrect PCM fueling tables). However since the narrowband O2 sensors (your stock O2 sensors are narrowband, 0-1 volt ) are ONLY accurate at stoich (or lambda, 1.00 in our case Lambda is about 14.7 parts air to 1 part fuel, 14.7:1) , that's the reason they get ignored at WOT

When you go WOT you then enter Power Enrich (there's a fueling tab that deals with Power Enrich) ... this requires the items in the view be met (MAP > x, RPM > y, TPS > z% etc...) but once met it uses the values in the V8 Mult table (the values are a divisor .... stoich/value in that table = commanded AFR... if your Volumetric Efficiency (VE) table is accurate then this your actual AFR should be very close to your commanded AFR ... hence the reason there's lots of emphasis on having your VE table properly setup... for more info on that see the stickies, there's one about VE tuning, also there's a howto in the help file I believe)


On a final note (almost time to watch simpsons ) for automatic trans tuning... part throttle shift points and downshifts are a personal preference... myself I have my car setup so that it will only shift into Overdrive (4th) above 50mph (so only at highway speeds) ... I also have my 1st gear pull longer (delay before shifting to 2nd, same for 2nd to third)

For WOT shifting... there are several tables ... there's NOrmal, Hot, and Performance (I think that's it?) ... Normal is used more os fthe time... if Trans Temp gets hot it uses the Hot tables... Performance requires a pin in the PCM be triggered (not hooked up from GM)

But.... WOT also has tables that indicate the desired RPM to shift at... GM wrote the PCM code thus that, BOTH conditions must be met (so for example a 1-2 shift set to occur at 40mph , w/an RPM value of 5400 means that the RPM must be above 5400 and speed must be at leats 40mph) ... what I generally do is change this to be RPM only driven (I set the MPH to shift low, but then set the RPM about 200RPM below what I actually want it to shift at... so if I want a 6500 RPM shift from 1-2, is set the MPH to say 20mph, but the RPM is 6300 ... that results in a shift right around where I want)

The shift tables also determine when a Downshift occurs... in my case I have it setup that my car never downshifts out of 3rd when I punch it (No sense... if I drop into 2nd I spin)


Hope that helps clear things up a little? The stickies have some good theoretical discussion and other documents that help (or are meant to) as well...

If you post up exactly what kind of tuning you want to do (not how to do it, but as mentioned previously.. transmission tuning, WOT tuning, part throttle tuning, etc...) we can append to the above (This thread may be a good candidate for a sticky depending on how much info we can capture in it)

 

I have been able to sit down and figure out what a lot of the stuff does in this thing. It's unfortunate that the HP Tuner software doesn't tell you what UNITS the numbers are in for most of the charts, but that's neither here nor there - it just makes figuring stuff out a little more complicated.

I've already determined how to change shift points, etc. although I can't seem to get the tire size thing to work right - the field won't let me enter a value. I just copied the "VSS pulses" value from the hypertech tune, though.

What I REALLY don't understand at this point is how to ensure that I'm getting the most power-conducive mixture and advance settings. Clearly, the best power comes from running as much advance as possible without causing detonation. But I don't know enough about how the stuff works to know how to maximize these misture and ignition settings for max performance... It looks like all the hypertech program does is give you some more advance, but it seems to me that there's more hp to be had by adjusting the mixture, too - perhaps at the expense of gas mileage.

And finally, I was also looking to create a tune that would give me outrageous gas mileage, perhaps at the expense of power, for when I take long trips. But again, don't want to lean it out so much that I cause engine problems and whatnot.

So I guess what I'm REALLY looking for is some thoughts on how to read the scan charts to determine if what I'm changing is having the desired effect... Know what I mean?

Thanks!

 

There is some discussion on efi101.com forums regarding timing and fuel and which is best for performance. Take a read there too as recommended above reading is your friend.

FWIW peak power and torque is very rarely at the point where you can get in as much timing as you can without knock. Some get best results at 25deg, while others swear by 30. Each engine is different, hence why tuning tools are essential. Best thing is to read heaps and log loads. Concentrate on one area at a time.

Best thing is to start with your VE table as Horst suggests and get that as close to perfect as possible, it will make everything else easier. You may want to get a wideband sensor too. Especially for PE tuning which might be 2nd on your list.