Technical Writer for Internet & Print Media
Best way to learn DIY calibration work
My latest project is to learn how to do ECM calibration work. The GM guys call it "cal". The hobby calls it "tuning" or "reprograming". However you say it, after nearly 25 years of using an aftermarket calibration engineer to tune my ECMs, I decided to learn to do the work myself.
The first thing i did was survey the market as far as apps one can use to do cal work. While there are several pieces of software out there, "HPTuners" is unquestionably the market leader right now and has been for a while. Another reason I gravitated towards "HPT" is that the aftermarket cal engineer who's done most of my calibration since 1995, Ron Zimmer, uses HPTuners in a lot of his work on my cars. So, with one of the best cal guys in the business as my inspiration, I acquired a copy of HPT. At first, I used the current release version, 2.22 but I just upgraded to 2.23 (beta).
I also decided that, rather than relying on on-ling help functions, combined with trial-and-errror and what I read on forms---75% of which is bad information--I decided to take a class on calibration with HPTuners. There is not a lot out there as far as educational material covering use of HPT, but I found an excellent source for it: The "Tuning School" of Odessa, Florida.
The Tuning School offers two kinds of courses, class-room, seminar-style instruction which is done over two days at a facility with a chassis dyno. These seminars offered in both Odessa FL and Las Vegas NV. The other type of class is a home-study program--The Tuning School calls it "Learn-at-Home"--covering the use of HPT on late model GM ECMs. There are three of these home-study courses, beginning and advanced ECM tuning classes and a GM electronic automatic trans tuning class. Right now I'm doing the beginning ECM class, which is titled "Tuning the Right way: A Beginner's Guide to Tuning GM Vehicles with HP Tuners Software".
The first engine I decided to calibrate is the LS6 in my 2004 Z06. I had already had the car "custom-tuned" by Westech in Mira Loma, CA but their work was all with the car's fuel and spark at wide-open throttle. Since then, I'd been having occasional DTC P0171 or P0174 (lean exhaust) set and, even when the MIL was not requested, the long-term fuel-trim function was adding way too much fuel at low rpm light throttle. There was no vacuum leaks and I attribute the unusual LTFTs at low rpm to the Granatelli MAF I put on the car.
Since the WOT on this car was already acceptable and I don't yet have a wide-band O2S which is required for WOT tuning work, I started with the Tuning School's lessons on calibrating the ECM's main VE and MAF sensor tables for better drivability through optimized fuel trims. Admittedly, you wouldn't normally take the class this way but necessity was the mother of invention, in this case since my part throttle needed work but the WOT was ok for now.
So, after a couple of nights reading and re-reading the Tuning School's material, I took the first whack at DIY cal work last weekend and, considering that, while I'd watched over Zimmer's shoulder for many years but had never actually done any reprogramming myself, after my first cal sessions, I was pretty amp'ed at the results.
After a session on Sunday and a second one on Monday I had made a significant improvement in the car's LTFT functions, having moved them from as much as +21% (above 23 turns on the light) down to about 3-5%. Not bad, considering my rookie status but...there is more to do over the next few months as I have to continue to fine-tune my 04 Z06 and, then, move onto my hotrod V6 Camaro, my 99 Blazer and my Wife's 07 HHR. I will be documenting some of my calibration learning experiences for an article I'm going to write later this year for "Auto Enthusiast" magazine.
I think the Tuning Schools home-study classes are pretty darn good pieces of instruction and well worth the money. They are far better than trying to figure out HPTuners by trial-and-error. You can be using HPT the right way in far less time. Also, you read those course books then figure out that a fair amount of discussion on forums about how to calibrate is bad info.
As for HPTuners itself? Well, it's a damn fine app. Actually it's a suite of two apps, "VCM Editor", which you use to program the ECM, and "VCM Scanner" what you use to record the ECM's serial data stream as it relates to the paramaters you are going to calibrate. VCM Suite's interface is reasonably intuitive. The software allows access to much of the ECM's programmable resources. The software installs and loads with no issues I can detect to date. It will run under Windows XP, Vista or 7 on a machine with a 1Ghz or faster processor and at least 512Mb of RAM. I use it on an old Acer 5670 running Win7. HPT has reasonably good tech support and a darn good web site with FAQ and user forums.
I'll post here again when I get a little farther along in my home-study activities.
Thirdgen.org is an excellent source of information and tools for the DIY tuner. If you go to their DIY Prom forum, you will find stickies to excellent articles and write-ups on tuning. Most deal with SD systems
but you will also find primers on hacking and disassembling ECM code. With the growing popularity of installing LSx motors in 3rd Gens, you will also find more discussion of PCM tuning and using LSx ignition on Gen1 and Gen2 motors. Other good sources of info and tools can be found at DynamicEFI, Welcome to www.moates.net! : Moates.Net, TunerPro and TunerPro RT - Professional Automobile Tuning Software.
Technical Writer for Internet & Print Media
I should have said in the OP that HPTuners only supports 1996 and up systems and my discussion relates only to 96-up ECMs with EEPROM memory which can be "flashed" during the programming process.
I've decided I'm going to tackle learning calibration work for those systems, first.
Let me know
I think you are fairly local to my shop so please let me know if you need local help with the software or a some dyno time to establish your gains...
Santa Clarita, Ca.
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