If you haven't read the Promgramming 101 over at DIY_EFI.org, I would suggest you do.

I've started a new series called Promgramming 101A over at the GMECM site. If you want to learn a bit more then just editing tables, better sub., to the list. It will be a slow process, but if your really serious about chipping you'll want to folllow this.

going to start off with just understanding what is in a prom/memcal, and go from there. The goal being to develope your own software, for your application. Instead of disabling say the EGR, we'll remove it from the code. Then we'll have room for adding things like timing vs MAT, etc.

If the demand is high enough, I might cross post it here, if just a couple guys from here then I'll just post at GMECM.

 

I'm interested.

Now, if I can just find it...

Seriously, I can't connect with either of the URLs...

http://www.diy-efi.org/gmecm/papers/prog_101.html

http://www.diy-efi.org/gmecm/

...But I did find a prog 101 at http://www.geocities.com/ecmguy.geo/bruce/prog_101.html

[This message has been edited by Sarkee (edited August 16, 2001).]

[This message has been edited by Sarkee (edited August 16, 2001).]

 

Arrgh,
I couldn't get there either.
I'll let Steve Know

 

OK; it's accessable again.

...But I don't see a Prog101A on the subscribe list...Still looking...

Subscribe to DIY_EFI??? OK.

BTW: The GMECM Prog 101 page is somewhat different from the Geocities Prog 101 page...Which is more current of the two???

[This message has been edited by Sarkee (edited August 17, 2001).]

 

I'm about ready to give up on this. Can't find any reference to it at DIY-EFI.ORG; I subscribed to the list, but there's no talk about Promgramming 101A...

Is this a joke???

Kinda funny, I guess...

 

The Promgramming 101A just had it's first 2 postings on GMECM. It's just starting, it's a work in progress.
Things like Programming 101 took several months to put together. This stuff is kinda complicated to wade thru and hard to just write up.

If I'm kidding you'll see a <g> or LOL.

 

Heh...Well, if it's that hard to find, then it's probably beyond me to understand anyway...

 

Thanks for bring this aspect of "prom tuning" to everyone's attention Bruce. Modifying the actual instruction set brings an entirely new dimension to Prom Burning.

For the "uninitiated", being able to alter the instructions allow you to make the ECM behave the way YOU want it to instead of how GM wanted it.

I have already added/modified a couple of instructions to make my ECM work differently than the way GM intended. One change was how I make the EGR function. I modified comparision to use the Vehcile Speed instead of the MAT temperature to overcome a driveability issue that always bothered me. Now, my EGR engages at 15 mph instead of using the MAT temperature to engage it.

Another was the invoking of Highway Mode Spark Advance. I made that routine enable based on Vehcile speed in addition to the other tests done my the ECM, and to use the RPM as a maximum threshold as opposed to a minimum threshold for engaging. I did not like the way the ECM engaged HMSA as it theoretically would leave it on at some ridiculous high speeds.

But the point is, only by altering the instructions am I able to modify the way my ECM now utilizes the various sensor information to work the way I prefer. And if people REALLY want to get into PROM tuning, altering the instructions is the next level. Then you can do virtually ANYTHING.

I think it would cool if we could somehow make "patches" to the code available to people that would like to "dabble" with this. Optimally, a download with a "subroutine" that could either be ORG'd into the Source code or "cut, editted and pasted" if their source code is radically different from the original GM source code.

 

Carl Summers at DIY-EFI mentioned this several years ago. Trouble was no one was willing to go out on a limb, and help him. In the interveining years, it kept coming up, and again no one would go for it. I'm hoping it's about time for it to work now.

Yes, when we have full control there is no limits to what we can do.
I always liked the idea of being able to just use patches and basically roll your own programs.
You want SEFI MAP V6?.
Just use patches 1-4, and 9 with the base calibration.
It also appears to me a 27128 prom is all anyone needs.
use a custom program without all the self diagnostics and there is lots of room.
Have a problem?.
Then use chip B.
Well, back to editing/commenting....

 

Were you reading my mind on my other post in "IAT/MAT - Final Answer"?

Yes, editting and commenting takes a VERY LONG time. I still have a ton to do with my Source Code. Unfortunately, I created/disassmbled my orginal Source Code after I was well into eprom burning and used a version of one of my BINs as my starting point. Once I am all finished, I can look at the possibility of changing it back to the original AUJP so Source Code would be available to everyone as a starting point.

Alternatively, I could re-create a disassembly of the AUJP that would give Source Code immediately to any one wanting it, but it would not have any comments. But, they could use the ANHT hac for descriptions in conjunction with the AUJP Source Code and just refer to the ANHT hac when they need some references. Then they could add "comments" as they go. This is how I initially started. But it would, at least, give them "assemblable" code and provide another alternative to using a BIN editor too.

Though I still find it easier to use Tunercat to make various "tests" and then alter the Source Code at certain times to reflect the current changes I have made...and add documentation as I make the various changes.

But I would be willing to donate "assembleable but currently undocumented" original AUJP Source Code. If interested (as a starting point for AUJP users), let me know and I will provide it shortly after I return from vacation.

 

Does that mean that we could possibly adapt a LT1 or LS1 MAF to our vehicles and do away with the 255 limit, or use the 730 ECM and make a LT1 PCM style setup?

------------------
89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-MSD 8.5 mm plug wires
-Gutted cat
-!AIR
-Gutted Air Boxes

 

You can't directly use a late MAF on any early ecm. The frequency range is way too different. The electronics is the problem. Once there is a translator, for handling that then anything is possible, but there is alot of leg work with that statment possible.

255 means two very different things here. One is the oem MAF is rated at 255 grams/sec., and the other is 255 as used in the Hex counting system, and is what the ecm works on. You can Have a MAF that reads to 510 grams/sec, but the ecm still can only read it as a highest value of 255. In the calibration you have to tell the ecm, that the limit is now 510 with a reading of 255. I use a 510 gm/sec MAF on my GN, and things are fine.