Whats in the ECM and whats in the programmable chip?

[PPPPPP42]

In hunting for a 7747 ECM I have found there are any combination of engines and transmissions that use that part number. Obviously its nice to get the correct one from the start, but if I will just be pitching the chip on it and putting a new one in its place such as this:
http://support.moates.net/g2-adapter-installation/
Does it really matter what ECM I get so long as its a 7747? Where is the info for engine and transmission and what not stored, I think I just read in another thread its on another chip in the ECM. If so is that chip reprogrammable or replaceable?

Is it possible for a 7747 to be completely universal so that I could move it to any TBI vehicle it will plug into and just swap programming?

EDIT: Btw that chip sandwitch you end up with following the instructions in that link is slightly hilarious, youd think someone could have come up with a more direct adapter.

[EagleMark]

1227747 are all the same. There is a smaller chip called a Netres that is the Limp Home. If catastrophic failure occurs in EFI system it has safe settings so engine still runs. These are differant V8 to V6 etc...

I solder the Moates G2 directly into ECM without dip sockets. With chip you can still install cover. No sandwich effect. Use a zip socket to emulate or while changing chips.

[PPPPPP42]

So two identical number ECM's aren't actually fully interchangeable unless they came from a vehicle with the same engine and transmission unless you swap the smaller chip out?
So what can be done with the smaller chip if you want to use the ECM in something else, especially if its an application that never used that ECM or another brand vehicle entirely? Do you just lose limp home mode? Is that the only difference other than the main chip then?

[JeepsAndGuns]

If you are wanting to run a V8, get a 7747 from a V8, that way the smaller "limp home" chip will be the correct V8 one. You can use a 7747 from a V6, but you will need to swap the limp home chip for a V8 one. Works the other way around if you have a V6. Its usally easyer to find a 7747 with the correct chip in it, than to find the chip by itself.
So yes, all 7747's are fully interchangeable. The limp home chip is what needs to be engine specific (V6 or V8). And of corse the main chip too.
Lots of people have converted older non fuel injected engines to fuel injection, myself included. What are you wanting to add injection to?

[EagleMark]

Even though they all have 1227747 on them, the BCC is differant for the chip and I guess it gets the matching netres. I just use a V8 or V6 netres depending on engine going into. No big deal here really in any vehicle. The main chip is the guts of the operation, small chip is LHM.

If you buy a new ECM it comes with no chips. You use the chips from faulty ECM.

[PPPPPP42]

Its not that I can't find the correct ECM I just want to understand exactly whats going on but in the past people kept telling me the correct thing to do without fully explaining what everything does which teaches me nothing.
Not looking for specific answers to a problem, just general theory.

So if I have this straight:
1. Without the 2 chips installed ECM's with identical part numbers are 100% identical no matter what engine, transmission, vehicle or year they came from.
2. The larger chip can be replaced with something that can be programmed for any engine of any size or brand or modifications so long as you know what you are doing.
3. The smaller chip is not reprogrammable and no aftermarket versions exist, and must be the correct one for the exact engine setup, significant mods to the engine or a change in engine would render the limp home useless and so the chip would have no purpose.

So unless you are using a stock engine or an engine close enough to stock that there is a limp home chip available for it then it doesn't matter which ECM of the correct part number you use because the limp home chip will be wrong and not allow the engine to run anyways.

Just to clarify the smaller chip is ONLY for the engine or does limp home include transmission data like the main chip does?

EDIT: I should specify again this is for the 7747 ECM which is the earlier style with the resistor pack chip totally seperate, I get the impression the later MEMCAL stuff has the things incorporated into the same chip thingy. Do keep in mind I am just starting to learn this stuff and may have misunderstood some of the basic fundamentals.

2nd EDIT: ok so I get the impression from this:
http://www.bsecorp.com/files/techtips/bdtecb103.pdf
that the 7747 is prom with separate CALPAC and the later MEMCAL assembly has the calpac built in.
Is the calpac resistor data generic sensor data that would work with any motor using the same sensors? I really want to fully understand how it does what it does.

I found this on another site, is this accurate? "A Calpak, a separate chip on the Calibrator Modules, normally provides the information to the ECM for rear axle gear ratio on pre 90 models."
That would mean that the Calpac is doing more than I thought.

[FSJ Guy]

You were good on 1 and 2. #3, sort of. :D After that, it starts to get fuzzy. "Technically", the 7747 ECM doesn't use what are called Memcals.

Sooo.... Back to #3. The smaller chip "Netres" is a NETwork of RESistors. Hence, the name. It has the limp home information that is used if the larger programable chip goes Kablooey. They are known to be different for V6 versus V8 engines. That's it. If you're running a 6 cylinder, get the one for a 6. If you're running an 8 cylinder, get the one for an 8.

What if you have a Chevy 454 V8? 8 cylinder Netres.

Got an inline 6? 6 cylinder Netres.

How about an AMC304 V8? 8 cylinder. What about a 401 V8? 8 Cylinder.

See where I'm going? All you have to do is match the cylinder count. For most people, that's all you need to worry about.

As you already know, (See #2), the "bigger chip" can be replaced with a user programmable chip to account for a whole host of different engine and vehicle parameters.

Memcals and such are usually the names given to "chips" on other more advanced ECMs (mid to late 90s).

[PPPPPP42]

Ah ok thanks, if the netres is only programmed with a cylinder count that's what I wanted to know for swapping it into anything and everything. I'd be curious to read exactly how a pack of resistors telling the system how many cylinders it has allows the ECM enough info to limp home on a variety of engines.
Is there a reference guide for part numbers for the netres or do you just have to know what the ECM came out of by looking up the 4 letter code for the main chip if nothing else?
Also when I try to research the netres I see them called a calpac instead, am I getting my parts confused? According to that PDF I linked they all have an 8 digit part number when they are the seperate little chip like I think I have.

I knew the memcal was for the later stuff (92 with automatic and 93-95 with auto or manual for obd1 right?) though I got a little rambly and confusing. I was just commenting on the fact that it appears the 2 separate chips got combined into one big one on the memcal stuff from what I was reading.

EDIT: It seems that calpac (or pak) and netres are interchangable terms but if you want to order one from GM you are getting a calpac.
I also found out that:
"16060836 is the (V8) one.
16060837 is the number of the chip without the plastic carrier and IIRC its a GM internal number."

[EagleMark]

Have you ever watched the Big Bang Theory? Sheldon... :laugh:

You'll have fun here other more knowledgable electronics guys. I'm more a car guy who learns as little as possible of electronics funtions, just what I need to make a car run... but I'll answer some.

It's really not a big issue, I have never needeed it to limp home and I've been driving these systems since 1988. I've done a lot of conversions and just stick V6 or V8 chip in... and never use it. Goal here is never need it!

1. Yes
2. Yes
3. I've seen heavily modiifed engines run on LHM. Not well but run, even stock does not run well but better, rich and not much timing or power. Safe but runs. Never intrested me how or why? I just fix the system so it runs correctly!

Memcals are more complex. There's some good threads around here on them. But not for the LH funtion, more run functions like cylinder count. It also has the knock module/ESC. One PCM covers more vehicles with a Memcal change.

No Etrans with these ECM so no trans funtions. TCC won't work in LHM, but I doubt you could drive that fast? There is a trans LH routine in etrans Memcal PCMs. But I don't recall it being part of Netres/Calpak.

The Calpak statement about gear ratios is not correct for these ECM/PCMs.There is a DRAC or VSSB that handles the gear ratio, speedometer signal from the VSS on the GM OBDI systems. Yes GM calls the little chip Calpak, people have called it Netres and some LH chip.

[PPPPPP42]

Funny you should say that, very not the first time I have been asked if I watch big bang theory (I have seen one or two) and been accused of being Sheldon.

I figured the gear ratio in any part of ECM statement was wrong as I just ordered a 7 pin dip switch (in quantity) to convert my drac so I can use the junkyard dirt cheap 3.73 gear axles I have (current is 3.42).

It makes sense that the older computers don't include transmission stuff in their limp home since they didn't change the ECM to a memcal type until the autos in 92 because of the need for the extra transmission controls among other things I'm sure (thanks for that year/application fact in another thread btw).

Eventually maybe I will tackle some GM engineer and get him to explain to me what the resistors do. Fake sensor data? Act as switches for preinstalled stuff in the computer? If its the second I would imagine they use the same set for different cylinder counts in all ECM's and its the stuff in the ECM it switches that changes.

I will also start looking at calpak numbers to see if there is really only one for each cylinder count or each ecm or what. I will look up the 4 and 6 cylinder calpak numbers for at least the 7747 (was this used in a 4 cyl?) later just to have them I think.

I mainly worry about the calpak being correct because many individual part failures will make it suddenly quite critical to getting home and I hate being stranded.

Most people do just want to learn how to make things work how they want without bothering with all the extra theory and details. It may seem stupid to want to know this much in depth, but if I know exactly what everything in the system does I can more easily learn tuning and diagnostics and predict what things will do. That's how I learned EFI in the first place, I just learned exactly what every part did and suddenly its super easy to diagnose EFI because I know which pieces are doing what jobs and I can rule stuff out based on symptoms and tests.
I also like to know in each type of ECM, what functions are in the ECM, calpak and prom.

There is a site out there where someone as messed up as I am was working to reverse engineer the calpaks to figure them out and even had the help of Moates, but I get the impression they gave up on it from what was on the site. He determined that building a custom one would be impossible since there is really no programming and any other type of resistor pack would be huge, not just a simple change like in the drac. He never did explain exactly how the resistors do what they do though.

[1project2many]

Limp mode is fuel only, no timing control. The NETwork of RESistors in the LHM chip is a simple analog calibration relating injector pulse to various input signals including coolant temp, voltage, MAP or TPS, and rpm. LHM can be duplicated and I know of at least one person who is having netres' made to include with remanufactured 2.5 liter engines supplied to the US Postal Service.

You will find that knowing too many details too soon will lead to a more complicated tuning process. Dropped in NYC with the goal of arriving at a specific destination, can you say the job is made easier or faster if you dedicate yourself to completely learning the subway routes, and street maps, and air traffic routes, and bus schedules, and "on call" service routes? You might make a helluva dispatcher when you're done but really, all that info to replace a simple set of directions? Or asked in another way, do you need to know how digestion works to enjoy a great meal?

GM did away with the redundant fuel devices in the '90s. The ecms are actually very reliable.

[romac55]

BUT , like Mark said ; once the smoke comes out , there's no way to stuff it back in . That's a great analogy ; finding a NYC address or becoming the best NY cabbie. Be safe...Bob.

[EagleMark]

I admire the intrest! But when your done you would be an expert on something that no one wants to use... never goes bad... and only comes into play if you mess up your prom burn or run without a chip...

[Six_Shooter]

I plan to one day, work out how the NETRES and RFD work in the P4 style ECM, but is not very near the top of my list. I did buy an O-scope as part of figuring out what does what on the NETRES, but I haven't found an official internal schematic of those NETRES DIPs, so I haven't started building my adjustable version yet. I know how I will I will go about testing changes, just want to make sure I'll have an accurate placement of the adjustable resistors to do it.

[PPPPPP42]

Ah, all very true, I should just start in a normal place and learn the basic how to's first.
Good analogy with the cab thing, though I'm the sort that would study all those extra things before choosing a course. I think I'm defective somehow. :rolleye:

I think I just got ahead of myself because I am always in shopping mode for future projects and asked myself, "If everything is in the damn chips why are there 50 different ECM's?" and so I wanted to know how everything was interrelated. I had sorta wondered if you could stick to a single ECM number (of a given EFI type of course) for absolutely any engine and just apply differently programmed chips for different projects, but the resistors for different cylinder counts in the netres baffled me and I wanted to know a little more about it.
I still have to figure out why people pick one ECM over another and the differences between any 2 basically functionally identical (not including chips) ECM part numbers.

At the moment I am reading the educational stuff on the Moates site, but I can tell it will leave holes, especially where the extreme basics and the more specific application stuff is concerned. So I will have to study elsewhere as well.
Is there a more basic list of electronic hardware somewhere with pictures and explanations? I still can't name any of the individual parts in that "chip sandwich" I linked to in my first post just by seeing them or tell what they are for.
EDIT: nevermind, after reading that G2 install instructions about 12 times and rebrowsing the catalog I think I get what is called what and what everything is for and what parts you skipped to make it lower profile which seems a really good idea.
That socket booster 1.0 seems to solve a problem with the ECM I was specifically looking at, is this weak communications a common issue? I don't know how much emulation I would be doing as I barely understand its purpose so far. If soldered to my ECM directly it seems it would eliminate several other pieces from the stack.
http://www.moates.net/socket-booster-1-0.html

[1project2many]

Good analogy with the cab thing, though I'm the sort that would study all those extra things before choosing a course. I think I'm defective somehow. http://www.gearhead-efi.com/Fuel-Injection/images/smilies/rolleye.gif
I doubt it. I get the same way. I've had to learn how to maintain focus and prioritize. These days I'd study the extra things as a hobby then join an internet group of individuals with similar interests to expound and expand what I'd learned. After arriving at my destination, of course.


"If everything is in the damn chips why are there 50 different ECM's?" and so I wanted to know how everything was interrelated.
Now that is a damn good question. And after years and years as a tech and tuner and curious guy myself, I've realized the answer is "Because they're idiots."

No, not really.

GM and Motorola did a lot of development work together for EFI starting in the '70s and GM was very heavily invested in the electronics side. Did you know AC Delco was the world's largest chip manufacturer in the late '80s? Bigger than Intel and Motorola Semiconductor. That must have been some expense to not only design the EFI and supporting systems but to create the manufacturing required to build the components they needed to assemble the control systems as well. I'd say management at GM was committed to using what they'd developed as often as possible. And this strategy made sense on paper but it probably made a lot of extra work at the design level. Re-using ignition control code and hardware designed for a distributor based system from the '70s, for example, meant either the code and control strategy had to be scrapped when distributorless ignition was implemented or the DIS had to be designed around the ecm's distributor based system. The same goes for the switch to port fuel, then to sequential port fuel, and also when forced induction was added. Plus there was a need to make existing (and aging) technology control more functionality as the demands of the customers were growing, the standards of the EPA were becoming more stringent, and basic engine control theory and practices becoming more sophisticated.

Then there's the final cost consideration. While it's nice to have a "one size" solution, GM North America had six divisions appealing to the range of customers from the guy that wanted a simple roller skate to the top end customer looking for a no compromises vehicle. In order to make a vehicle for everyone there were huge variations in vehicle options. Port fuel, sequential fuel, throttle body injection, distributor and DIS, electronic, non-electronic, and manual transmission, digital dash and automated climate control systems, active suspension, even entire vehicle integration were all offered during the same time frame. Including the code and hardware for six cylinder multipoint sequential injection in basic, single point four cylinder TBI equipped vehicles would have driven the cost of an expensive controller even higher ultimately affecting the final price of the car. Using an ECM able to communicate with the climate control, Bose audio system, suspension controls, and electronic trans in a six cylinder manual trans equipped stripped "Work Truck" series pickup would have driven up the cost of the final product and would have left a bad taste with the customer if they ever had to have that expensive controller replaced.

Finally, GM still hadn't fully integrated powertrain engineering for the different carlines which caused divergent solutions to similar problems. Sometimes different ecm's were used, sometimes different engines in similar vehicles, and plenty of times you'd find different accessories on the inside. Even in cases where the ecm was standardized across carlines, you'll find calibrations that are brand specific. Ultimately controllers and code were modified, optimized, and dedicated to a powertrain and / or vehicle. The large number of different controllers and hundreds of different calibrations is the legacy we're left to with.


I had sorta wondered if you could stick to a single ECM number (of a given EFI type of course) for absolutely any engine and just apply differently programmed chips for different projects,
Excellent question. Well, a controller's a controller. Signal in, process, signal out. So providing the supporting hardware and code required for your vehicle is present, the answer is "yes."


but the resistors for different cylinder counts in the netres baffled me and I wanted to know a little more about it.
There has been discussion about this here with the goal to use "wrong" hardware in a specific application. The resistor network that was available separately on the 1227747 and other "C3" ecm's was moved into the "memcal" in P4 and later ecm/pcm's. Questions about the netres are still relevant and because GM didn't like to throw anything away. Chances are extremely good that the part functions the same way despite the ecm changes. For most people the netres problem has a simple solution. Get one from an application with the same number of cylinders as your engine and don't look back. If you could build custom resistor networks tailored to a specific engine that would be cool but most people don't ever have to worry about it.


I still have to figure out why people pick one ECM over another
Well, that would probably require figuring out people, which I'm guessing you have as hard a time with as I have.

For me, major considerations for implementing EFI on vehicle not previously equipped and which will require some effort to tune are:

1) Is the hardware included to support my engine/fuel system/ignition choice?
2) Is code available to support my engine/fuel system/ignition choice?
3) Does it provide enough data in a fast enough manner for me to get tuning done as quickly as possible?
4) Is there tuning software available which allows me to make the necessary changes?
5) Is it commonly available in junkyards or in parts stores?

People working with OEM EFI equipped vehicle don't usually change ecm's unless they feel the current controller is limiting them in some fashion.

[/quote]and the differences between any 2 basically functionally identical (not including chips) ECM part numbers.[/quote]
Another big question. This was more prevalent with the C3 ecm's because in those units, the program that runs the ecm is on a chip soldered to the board. The large replaceable chip contained small code segments but was mainly populated with calibration data. So if you had a truck with TBI, for example, and you thought it might be nice to have intake air temperature compensation for your spark and fuel, you would remove the 7747 ecm which didn't have supporting code for the IAT and replace it with one from a car. With the P4 and later controllers the code was moved into the memcal allowing fewer part numbers to service more vehicles.

[EagleMark]

Here's some files I found.

[PPPPPP42]

Hmm, all very interesting and informative in both your posts. Too bad those files don't have more types of stuff in them to compare.
So the pre memcal GM obd1 ecms are C3 type and the memcal type GM obd1 ecms are P4? Too bad they didn't stick with the C's it would amuse me greatly to tell my friends my truck runs on a custom wired block of C4.

If I am understanding right, rather than the big goal of building a netres from scratch I think you could reroute the actual leg for pin 56 on the memcal type and I think I read somewhere it was pin 9 on the C3 type through a simple removable computer jumper and you would have a V8/V6 switch, then you could either switch bins with one of those multi program switchamabobbers (technical term) or just swap the prom out to go from V6 bin to V8 bin. Probably just as easy to switch the V8 vs V6 netres on the C3 but if its part of the main memcal on the P4 perhaps such a jumper would be helpful. Though it looks from those diagrams like a bunch more crap was crammed into the netres functions for the P4.
I wonder what people do if its a 4 cylinder, I assume when they refer to that pin being a "V8 switch" they mean between 6 and 8 cylinders, I suppose the 4 cylinder was its own thing entirely.

Something I have been considering is getting a 7747 for my 4.3 truck now and then just changing the programming when I get the 5.7 installed, it would give me time to buy and learn the tuner a bit before I have the expense and time of putting the new motor in on top of everything else and I don't want to resolder stuff on an ecm only to have to get rid of it. With a 7747 and a v6 and v8 netres I assume I should be able to do that.
My current ecm is 16144288 AZUS I figured I could take a 7747 with whatever its version of AZUS is and then when I get a V8 just swap the netres chip and load ARHT-$42-5.7L-Manual.bin‎ which is AZUS with a 5.7 more or less I think.

I'm waiting at some point for someone to just tell me to shut the hell up by the way. :)

EDIT: Ran out an pulled my ECM quick (3 minute job on '92 K1500 I love that) I was under the false impression that the netres was a removable chip in a socket next to the prom from pictures, but in my ECM its soldered in, hmm, maybe I have the wrong chip, better take it futher apart and make sure :)
2nd edit: yep I'm pretty sure thats the netres soldered to the board, what a pain in the ass. And it was nice of them to coat the the whole ecm board assembly with clear goo to waterproof it (after programming I guess since they coated the slot connector on the end too) but they didn't let it dry before jamming it in the case so its nicely glued to the insides making it fun to get the daughter board flipped.

3rd edit: found that post with the "pin 9" reference http://www.thirdgen.org/techboard/diy-prom/284940-netres-part.html
if 7747 V6 ECM's are much easier to find than V8 ecms as one person in that thread said than a V6/V8 jumper switch would make a really useful addition, especially if all these F'ing netres chips are soldered in. I was so sure I saw a pic of it in an unpluggable installation.

[EagleMark]

We won't tell you to shut up or go away. But have been trying to tell you not to worry and move on. No one here will stifle intrest or research, but we have told you it's not worth the effort.

16144288 is same ECM, but like you found a permanent netres. Just plug in a 1227747 and go on with life.

[PPPPPP42]

Ok, thanks for the info, will be moving on to 7747 though it was useful practice getting this one this far apart without breaking anything, they literally dipped the whole damn ecm internals in some sort of clear rubber potting goo right up to the 2 main plugins and then stuck the prom on it (socket musta been capped for dipping). Which means that the daughter board which has to come loose to desolder the prom socket was glued to 3 sides of the case and the black center support pin was glued in plus the 2 cork spacers were glueing it to the ribbon cables, all apart now, quite fun actually. This may all be old news to you guys, but its part of the "basic stuff" that nobody ever really thinks to mention. Totally not mentioned in the moates G2 install guide.
I will snag a 7747 in the next few days and find a v6 chip set somewhere too.

[gregs78cam]

Just wait until you get the itch to upgrade to a '7427......:rockon:

[1project2many]

When the diy-efi.org and gmecm mailing lists were going strong there was a lot of this type of discovery occurring. Now it's nearly 20 years later and there are fewer people interested in the magic of why and how GM did what they did vs how to get these older vehicles modified and hotrodded. The archives are currently available to view and there is some good reading to be found.

Can you see through the goo enough to read numbers on your netres? I'm wondering if they match other TBI netres.

The 7747 is usually sold as an ecm minus chips, even by the junkyards. If the chips happen to be in the box when you buy it, well, then you've gotten lucky. Often the best way to obtain the right one is to visit a "pick a part" or to watch classifieds on forums or craigslist. You could also check the GM dealership to see

[PPPPPP42]

7427? Do tell.

And the netres in my 16144288 AZUS is stamped 16051537 (ends in 6 if you try to order it new because it comes with the carrier) which also happens to be the chip in the V6 7747, so yes its the same, the bastards just soldered it on, I could desolder it and solder in the socket for a 7747 setup if I felt like it but there's not as many bins for the 4288 so why bother when 7747's are so common I guess.

Vehicle is '92 K1500 W/T with vin Z 4.3L and the getrag 5 spd stick and 3.42 (soon to be 3.73) gears if you are interested in the application.

O hey while I have your attention can the autoprom APU1 do any other brands than GM obd 1 for any functions? the description kinda implys that and I see that it comes with TunerPro RT5 which I think supports damn near everything and it looks like the ALDL cable is the stanard RJ whatever the hell plug in on the unit side so I could get any OBD1 cord to plug into it. In fact an OBD2 cord should plug in also.
I had a friend asking me about 80's fox mustangs and such which seem to be a whole nother ball of crap to work with, not just a prom swap. But that's for a different sub forum.

[gregs78cam]

'7427 was basically the final OBD1 TBI PCM put out mostly in trucks/vans to cover most any engine/trans combination. Way more tables and constants to change, faster ALDL stream (~6 samples per second vs. 1 sample per 1.2 seconds) with much more to see, and a few extra things that users have figured out how to add for functionality(WBO2, E-Fan, MPFI). I honestly don't know why people keep wanting to start out with the '7747. I had the '90 TBI engine in my '74 truck running on both the '7747 and now the '7427, the latter actually does run better, and transitions smoother.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?173-1227747-to-16197427-Conversion-PCM-Swap-with-Wiring-Pinout-Directions!

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?137-0D-0E-Efan-control&highlight=E-fan+control

[PPPPPP42]

I will keep an eye out for 7427 ecm's to play with later.

The 7747 is a direct plug in for my current ECM wheras the 7427 apparently is not so its not the best choice for me to start with. If the 7747 can do all I need and is better developed programming wise there is no reason to change up to the other yet but I will look for one as this is just the sort of thing I love.

I have saved this link for later: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?303-16197427-PCM-Information-OD

If its relevant to understanding any of my motivations, my current truck is a 5 spd because I absolutely hate automatic transmissions, so I will never need any transmission functions.

I have discovered another gap in my basic knowledge, understanding exactly what these "masks" are all about where bins are concerned, everyone always references certain ones for certain cars. Like apparently with a 7747 I am supposed to use a $42 mask or some such thing.

I also need to learn more about wideband O2 sensors incorporated into the system rather than stand alone seperate with a gauge.

I really need to stop hijacking my own thread with new questions before the old ones (autoprom apu1 versatility) are answered, but at least I don't flood the whole forum this way and there is just SO much to learn that is scattered across too many pages and threads to be totally coherent sometimes.
Has anyone written a worthwhile book on this? I see a few on amazon.

[EagleMark]

Even when the newer 7427 was available they did not use it other then Auto Trans but you can use in manual. 7747 does fine and is SO much simpler to learn on but will not control an eTrans. My 90 Chevy $42 7747 runs fine, no issues and get's better fuel mileage then my sons 7427 truck, the 7747 also get's better MPG then my 98 Vortec truck, I'll be trying to fix that by changing PCM to a 0411 LS PCM which is more defined (has more hex hacked to useful values). The reason the 7747 is best C3 ECM is because it has been fully hacked, same ECM as all other C3 but different masks are not all defined, if there's anything else to be had to include in Mask/definition/XDF it would not help. There is so much in 7427 Mask/definition/XDF it can be confusing and counter intuitive for anyone, especially a newbie. Many things should not be touched and don't touch anything you don't know what it does. Always save your tunes and number them to fall back on when something goes wrong.

Wide Band O2 sensor is a great tuner tool, but for a stock vehicle the only thing it's needed for is to dial in tune WOT. It can be used many other ways.

Read this thread and you will come to understand terms and be able to look up different masks. I've combined and improved the $42 defs for years, they have all the bells and whistles that TunerPro offers. I've yet to see any other XDF or ADX built as well. The thread below has been read 2473 times so it must help?
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?466-TunerPro-starter-Tutorial!-New-users-this-is-a-must-read

There's other threads that will help understand TunerPro, getting used to the software will be much more useful then understanding a netres chip and it will help you understand how an EFI system runs, what the data means and how to adjust it.
http://www.gearhead-efi.com/Fuel-Injection/forumdisplay.php?27-TunerPro-Tuning-Talk

Books from Greg Banish who runs a EFI tuning school are good reads, there's also DVDs, but most will be more then you can understand or put to use short term.

[FSJ Guy]

Just carry an extra ECM for peace of mind. I've never had to swap one out and yet I still have 2 or 3 spares.