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Bottom line up front.   This really rambles a bit at the moment.   But this write up documents my trek through editing ECM files for my 1989 Pontiac Trans AM GTA Firebird.     In order to load customized tunes in the 1227165 ECM one has to adapt a flashable chip to the OE MemCal setup.    The hardware and software to accomplish this was readily available in 2005/6 when I created my setup.    Many of the products I put to use here have a different future today.   Where I can document the current day product I will publish a link if I can drill down on one that is accurate.   Thanks for following my journey.

0ver the last 20 years I have successfully used products from John at TunerCat, Craig at Moates and a few others, to create custom tune files and burn custom EEPROMs that fit my '90 Camaro RS, '95 Astro Van, and now my '89 GTA.    All these started because of the success I'd had with LT1 tuning products from TunerCat, and the ease with which I could make changes to the PCM in my OBD-1  converted '96 Impala SS.  I also have TC's OBD-2 package.  I owe much of this success to friends in my Impala Club as well as Bryan and Alvin who were then PCMFORLESS and TC at TunerCat, Andrew at AKM Cables and Craig at Moates.net.

Making custom tunes and burning chips is not hard.   You just need patience, a couple of essential software and hardware tools, and a desire to learn something new.   I was fortunate to purchase TunerCat OBD1 (and OBD2) software from John at Tunercat in 2005 or so.   Primarily I was making static changes to fan temps, VATs and the like.  PCMFORLESS was a Bryan and Alvin entity at the time and Bryan tuned my LT1 Impala on the dyno in 2004, and Alvin did the same for my L98 GTA in 2005 if I recall correctly.

Most every GM fuel injected engine management system has an aftermarket product that can modify the baseline GM files.   How to get that modified file into your flash based PCM, or chip based ECM is the next challenge.   An exception today is my 2022 GMC Sierra, for which GMC kindly locked the PCM, but there is hope on the horizon for unlocked PCMs in the aftermarket.

I have continued my use of TunerCat for my 2018 Tahoe, 2004 GMC Yukon, 2002 SLP Camaro SS and my '89 Trans Am Firebird.   TunerCat for OBD1 is still available from TunerCat.com!!  (link below)

For this page I want to concentrate on the GM chip based ECM's in the 3rd Gen F-body.    TunerCat has what you need.   Once invested you will always be able to make adjustments to your tune with ease.  

For my 1989 5.7 L98 Firebird I use TunerCat OBD1 to edit my original Alvin Anderson file, continuing with a couple of subtle changes.    TunerCat OBD1 allows me to edit the file currently in my ECM and has a built in interface to burn chips.  Craig Moates designed and sold an adapter to hold the original GM EPROM and a 'Many-Time Programmable 27SF512 chip.    TC now offers 2 different kits that has all you will need for OBD1 editing and burning to a flash chip.

Craig Moates used to produce the software and hardware 'burner' for this.   TC at TunerCat implemented that support directly into his OBD1 Editor.  TC sells a complete package as his OBD1 Pro Tuning Kit with the editor, a single definition file, the burner, the EEPROM to Flash adapter and a blank 27SF512 chip.  TC's Pro package additionally includes an OBD1 ALDL cable, which you will NOT need on a ThirdGen F-body to pull/load tunes.  3rd Gen F Bodies are NOT directly flashable.   However that cable can be used for diagnostics if you happen to have a OBD1 diagnostic package such as DataMaster.  The ALDL cable in his OBD1 Pro kit can be used on any OBD1 '94 or '95 Impala or F-body, which do support direct read/flash.  To use that cable to edit OBD1 B or F body cars you would need a ECM definitions file specific to your vehicle.   ($19.95 each)  TC's definition files are NOT VIN specific but year/make/model/engine specific.     The ECM definitions file is basically a template that knows where each changeable value is in a particular ECM flash file.   As an example TC's $6e package works for 1989 Y and F cars, 5.0 and 5.7s.   Each different vehicle will have a unique 'template'.   Again TC's product is NOT VIN locked.   A big deal back in the day... and even today.

Here is a picture of the individual components of my setup.   Again... purchased in the 2007 or so time frame.

From TOP: 

OE ECM Memcal broadcast code AUJM  -  from my OE ECM, installs on the top header of the G1 adapter.

G1 adapter  -  allows parallel use of the Memcal and 27SF512.   Memcal is used for limp mode settings, 27SF512 where all other settings are stored

27SF512 flashable chip

Craig Moates HDR1 Memcal Header adapter -  allows reading of the 'data' from the Memcal, and which you can then open and edit with TunerCat OBD-1

Craig Moates Burn2 Chip Programmer  -  Connect via USB to laptop and allows TunerCat OBD-1 to read Memcals and flash 27SF512 chips.

Moates G1 assembled w/ Memcal and 27SF512, ready to insert in GM 1227165 ECM

GM 1227165 ECM with Memcal/G1/27SF412 installed ( w/ Memcal access covered removed )

As an FYI the TunerCat software editor for OBD-2 was sold in about 2010 to JET Performance and then rebranded as JET DST.   TunerCat OBD-1 editor is still available from TC at TunerCat, a link is below.    Moates hardware closed up shop in late 2022... and very sadly their products no longer available.  TC at TunerCat sells a OBD1 Tuning Kit with his OBD1 editor, a single ECM definition file, a USB driven flash programmer, EEPROM/Flash chip adapter, and a blank chip.    His OBD1 Pro Tuning Kit has all those same components plus an ALDL cable.    TC can also (typically) supply you with the latest OE file for your specific for your vehicle.  

I will research other items soon and post current info and any updates I can verify.  

A few links:    ( 11-06-2023 )

TunerCat OBD-1 ECM Pro Kit - 
Includes everything you need.  The tune editor software (Windows), cables, USB chip burner, a flash chip, and MEMCAL to flash chip adapter - Link >   TunerCat OBD Pro Tuning Kit
( I verified this with TC at TunerCat, he is still selling these kits as of Sep 2023)

Red Devil River -   This looks like someone who has products very similar to Craig Moates.  A good selection of tools.

Website:  Red Devil River

On Ebay:  reddevilriver on eBay

JET Software and Chips

Website lists stage 1 and stage 2 chips for my '89 L98 GTA that include the MemCal adapter.   I did not explore further, and did not readily see OBD1 editing software

Website:  Jet Performance Products – JET Performance Automotive Parts (jetchip.com)

eBay:   Jet Performance parts are listed on eBay from a small variety of vendors, search by company name

Internet Archive static historical pages,

(also known as The Way Back Machine.)

1.  Craig Moates and his fantastic product lines.   Moates.net

2. 

gem 11/06/2023 1:10 PM