Okay, so I've been digging around the GM service sites all day, and I ran across some funny things... read this:
"A new PCM programming adapter harness J-45411 is being sent to all Cadillac dealers for use in programming PCMs on DeVille, Seville and Eldorado models. You will use this harness to connect your Tech 2 directly to the PCM in these vehicles. When programming any PCM, it is critical that there be no interruptions during the programming process. On many vehicles, there is a large number of on-board comput-ers (as many as 24 on some cars). If one of these computers should “wake up” during the PCM programming procedure, it could cause permanent damage to the PCM.The J-45411 harness permits you to isolate the PCM from the vehicle's electrical system so the behavior of other on-board computers will not cause an interruption The J-45411harness connects to the PCM, to an underhood source of battery voltage and ground, and to the Tech 2. A red LED on the harness remains lit as long as the harness is connected to bat-tery voltage and ground. A yellow LED illuminates to indicate ignition voltage is applied to the PCM. When the switch is toggled on, two green LEDs illuminate to indicate PCM activity. A complete set of instructions comes attached to the J-45411 harness. Follow these instructions carefully, to avoid problems . N O T I C E : It is critical that all J-45411 connections to the PCM, power and ground stay connected throughout the entire programming procedure. Failure to follow these instructions may cause interruption of the PCM connection, power or ground during programming, and may result in permanent damage to the PCM. Dave Roland contributed to this article."
NOW, my question is, they point to the idea that you can reprogram the cdaddy OBD2 PCM's with a Tech2 and a special harness, right? Well if that's the case, somebody with a couple of extra bucks who wants to make ALOT of cash from all us Northstar consumers, should buy this and win all of our business: http://cgi.ebay.com/ebaymotors/ws/ebayISAPI.dll?ViewItem&item=1827262099&r=0&t=0
"GM’s Service Programming System merges your Tech 2 Flash, a required PC, and GM’s SPS CD-ROM, and lets you reprogram controllers on ’93 and newer GM/reprogrammable controllers."
OR just buy the whole kit from AES (the above link) for $2,999.00... now, we all know that's alot of money, but we're talking about ANY General Motors OBD-II ECM. Think of all the money you could make off the hotrodder audience? There're a TON of people using 3800s and N*'s EVERYWHERE, from dunebuggies to motorcycles to all of our little pontiac babies, and it's not too bad when you compare it to the $1200 for that holley commander for a N*, which even when modified STILL doesnt have everything we need to control the 4.6 properly... anywho, I'll stop ranting now, I just thought the word should be out if it already isn't...
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02:03 PM
Nashco Member
Posts: 4144 From: Portland, OR Registered: Dec 2000
I'm fairly sure you're missing something in this setup........what are you trying to do with it?
If you're trying to *modify* calibration settings (fuel/ignition curves, etc.), I don't think this will do it. From what I understand, these tools just flash new calibrations into the ECM. They use existing calibration files (for updated emissions, driveability, etc. files from the engineers) and replace the old calibration in the ECM. This wouldn't do anything for "hot rodders" that a factory ECM doesn't already have for them.
Anybody have a better idea of the truth in this?
Bryce 88 GT *typo*
[This message has been edited by Nashco (edited 05-08-2002).]
Yeah, you're missing the information to know what to change. You don't get to dial up "Rev Limiter" and oh, change it to ah, I think 7500 is a nice number.
You get to send the information to the PCM. All that for $3000 and you still don't know *what* to change.
If you look at page 3 of 4 on that .pdf file I linked to, it shows a screenshot of the pc end of the software for the Tech 2, and it looks like everything is clearly labled. I'm not arguing with what you say, you probably know way more about this than me. I just thought I'd point it out...
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05:02 PM
LS1swap Member
Posts: 1181 From: McHenry,IL.USA Registered: Jan 2001
Don't they have something like LT1 edit for the northstar??? With it you can keep DTC from setting and remove hings like emisions and VATS check out www.carputing.com
looks like one more piece of a BIG puzzle so this is a way to change stuff!!!! now we need hackers to de-compile the code to start to understand what does what, when and how it all works not a quick or eazy deal just one more clue and some tools to play with maybe others are farther along in understanding how to turn off missiong inputs WE can't be the only ones hacking GM's codes
------------------ Question wonder and be wierd
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08:48 PM
PFF
System Bot
artherd Member
Posts: 4159 From: Petaluma, CA. USA Registered: Apr 2001
------------------ Ben Cannon 88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives" 88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"
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09:12 PM
indyfiero3 Member
Posts: 68 From: belleville,ill. 62223 USA Registered: Apr 2002
hi everyone--been a caddy tech for 16 plus years---mr.nashco is correct.reprogramming does nothing for the hotrodders. only slight adjustments here,there.all driveability/emissions related stuff.this is still a cadillac,guys.art
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09:49 PM
Will Member
Posts: 14278 From: Where you least expect me Registered: Jun 2000
Originally posted by MickeyAsh: Okay, here it is, the whole story is explained. You can reprogram ANY 1993 - 2000 GM Engine Controller
No, you can't. In '93-'95 most GM controllers were still using PROMs. I think only the LT1 was flash. Things didn't go flash across the board until OBDII in '96.
Anyway, this software is ONLY for replacing one calibration with another pre-existing calibration. There is NO WAY included with the software to tweak the calibration itself. The screenshots show monitoring software, not tuning software.
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11:30 PM
Will Member
Posts: 14278 From: Where you least expect me Registered: Jun 2000
Originally posted by LS1swap: Don't they have something like LT1 edit for the northstar??? With it you can keep DTC from setting and remove hings like emisions and VATS check out www.carputing.com
Compare the number of people getting radical with LT1's and LS1's in their original chassis to the number of people modifying N*'s in their original chassis and you'll see why there's no Northstar Edit program. Most of the guys who put N*'s in other chassis just go with stand alone controllers.
Developing a flash reprogramming program is a tremendous amount of work. Just check out the prices on the OBDII LT1 and the new LS1 software.
Damnable... I guess I'll be going with the Holley, eh? Anywho... I still think that in this category, supply creates a demand... if someone made a N* editor or a mod ECM with all the stuff we need and none of the stuff we dont, they'd have a few handfulls of customers every week IMMEDIATELY, and from then on, when the N* made it's presence a little more known, people would begin to want it, and *boom*! There's your demand for the next few years... just my humble opinion... maybe I'll go with the 4.9... who knows... just thought I'd share what I thought was useful knowledge about the Tech2, hehe. L8r!
It would be far less expensive to just use an eprom based PCM (OBDI) that could provide the correct outputs for control of the Cad injection/ignition systems. There is a diverse variation of GM eprom based PCM's available, and many of the more popular versions have already had their code mapped to at least some extent. I am sure there would be at least one of these that would fit this need. Perhaps when I finish with the turbo V6 code that I am developing, I could spend a bit of time on some code that would function more universally for the cad motors. Although OBDII PCM's are quite expensive for a DIY'er to reprogram, you certainly do not need $3K worth of equipment to burn an OBDI GM eprom.
