ladystoy69

blaaah, so after gathering and collecting everything i might possibly need to do a 165 ecm swap, scan/datalog, program/burn i find out that the needed memcal has to be or at least should be from a corvette with same specs such as 350, auto and gear ratio and not just any ol' memcal such as from a 305 camaro.
is this true info? im not asking if i can get by with other memcals but rather if these are truely differant or not.
i'm refering to the memcal not the prom chip mind you as i know that can be anything i know.

if they are truely differant does anyone have any from vettes setting around to get rid of?

ok i found this post.... HERE
and i would rather not just be close but rather it be right or as right as it can be at least. any advise?
for example i read that the calpak from corvette has some sort of knock sensor cercuit as well that the camaro doesnt, this true?

Cliff Harris

There are several factors that determine if a MEMCAL from another car/ECM will work in your ECM. Obviously it must physically fit...

The 4, 6 and 8 cylinder MEMCALs have different connections in the resistor networks. The ECM checks those connections and the engine will not run if they are not correct (you'll get an error code 41 "cylinder select" error). That said, it is possible to modify a 6 cylinder MEMCAL to run in a 8 cylinder ECM. i have seen info on how to do this. I don't know about modifying a 4 cylinder MEMCAL.

The resistor networks determine spark and fuel in LIMP mode. The odds are quite good that you will never go into LIMP mode, so that may not be a factor for you.

Early Corvettes have an external knock sensor module (called an ESC -- Electronic Spark Control). I'm not sure what year it got incorporated into the MEMCAL. It was around 1989, I think. Some Camaro MEMCALs have knock sensors. I know there are differences in the ESC modules so there may be differences in the MEMCAL knock sensors also.

All the calibration data for fuel and spark is in the EPROM. That data varies widely even from year to year within the Corvettes so its important to get the correct EPROM for your vehicle. One thing you can do is get the correct .BIN (for binary) file for your car, program an EPROM with that data and put it in your MEMCAL.

I was working with Craig Moates on a universal resistor network PC board that would plug into a MEMCAL and allow you to put your own chip resistors on it. That was at least a year ago and as far as I know nothing ever came of it. Either it got too complex or too expensive to be practical.

MrWillys

A Camaro .bin file has an anemic spark map compared to the Corvette .bin. This is why I created a file for you. I gave you an 89 file that was modified for a cast iron head. It is extremely close to the 85 file. The only thing it lacks is reduced fan temps. People have a tendency to over complicate things, and not accept learned knowledge of others.

Feel free to compare what I posted with other L98 files, either F or Y body and you'll see what I mean. I will recommend your base memcal be from a tpi based 7165 car. What you burn to it is your choice.

ladystoy69

yes , this i know and i plan to use that bin on my chip.. the question was only really refering to the mem-cal/calpak (limp home and whatever else is in there) part of it.

the ecm and mem-cal/calpak i had been told was from a corvette when i bought it but now after checking numbers/codes i find it is actually for a [305cid, 5.0l camaro automatic california] and my plan as you know was using it in a 85 corvette 870-165 swap.

i already know the ecm is fine and same as used in corvette for the swap and the eprom dosnt matter as it is getting changed so ya was only the rest i'm questioning.

btw when does the ecm use this limp home info? is it used like if a part fails? like unhook a sensor then it refers to limp mode? if so i can see that possibly causing some issues, im probably wrong though lol

Cliff Harris

That is one of the great mysteries. I have never seen a definitive answer as to exactly what causes the ECM to go into LIMP mode.

I'm investigating that right now. There is a \LIMP signal in the ECM that connects the microcontroller, voltage regulator/supervisor and the FMD (Fuel Management Device). The mystery is which of those chips initiates LIMP mode? I have been thinking it was the FMD because it would then kill the microcontroller and take over the fuel and spark (all the fuel and spark control is done by the FMD). There is another chip that connects to the resistor networks and feeds data to the FMD. It has only 3 sensor inputs: TPS, CTS and DRP (Distributor Reference Pulses). It has only one output (INJLIMP) that goes to the FMD chip.

Bob Rauscher (of DynamicEFI fame) speculated once upon a time that the ECM would go into LIMP mode if the battery voltage got below 10 volts. I don't know how he came up with that. The fact that the \LIMP signal is connected to the voltage supervisor chip might have something to do with that. I've been meaning to test that...

A couple of days ago I found this in the '86 FSM (page 6E-7):
"FACTORY TEST MODE, BACK-UP OR 3.9K MODE
When in this mode, the ECM is operating on the fuel back-up logic and calibrated by the Calpak (back-up chip). The Calpak Part of Mem/Cal is used to control the fuel delivery if the ECM fails. This mode verifies that the back-up feature is OK. The parameters that can be read on a "SCAN" tool in this mode are not of much use for service."

When I was doing my ECM firmware investigation a few years ago I remember finding a section that looks at the voltage on pin B of the ALDL connector. It decides what to do based on that voltage. There are four possibilities: open (normal), 10K mode (diagnostic mode), 3.9K mode and shorted (ALDL mode). That says that there is some code to handle the 3.9K mode, which equals LIMP mode according to the FSM, as quoted above. I plan on looking at the code to see what else causes the ECM to call those routines.

You can go look yourself. See my web page on the ECM firmware in my car:

http://home.earthlink.net/~cliff_har...5/BUA/BUA.html

Here's a sneak preview of the code that does the voltage decoding (roughly around LC8A0):

It sets bit 7 of the "? mode" byte (I don't have a name for it), which signals 3.9K mode. What it does after that remains to be seen...

ladystoy69

how is one to reply to all that except um wow looks like tons of knowledge in that post and sad to say most of which is way over my head but still very interesting to say the least.

i am just still simply trying to learn what the data in logs are trying to tell me, data in bins mean and understand all the peramiters as i want to learn to truely understand what and why when changing stuff , not just burn a bin and call it good enough, or copy someone elses and be done(except for a starting point) but rather truely know how to tune but trying to figure out the calpak might be just a lil too advanced for me atm

anyhow i am gaining a lil knowledge slowly and been logging.. making adjustments to car timing, idle, etc and relogging just watching logs and learning some different effects of those changes atm.. slowly but i will get there.. and thanks for trying to give me vast knowledge but im afraid atm thet knowledge is kinda like filling a 2 gallon pail with 10 gallons of water lol

Cliff Harris

A friend of mine stroked his '89 out to 383 cubic inches, with some pretty extensive mods. He went through almost 30 versions of his tune before he was happy. Take it slow and keep going. You'll get there.

ladystoy69

lol funny you should say that because that was the first planned project , the complete 383 engine, polished hsr, twisted wedge heads, stainless headers and all the trim is just sitting on the stand now as i shelfed that idea wanting to keep the vette a bit more practical to afford to feed.

but ya thanks for the confidence builder.. i'm pretty sure i will get it figured out and maybe even some day put that stroker to use in something.

btw did you see in my other thread where this has a hypertech chip in it, wondering if that may be giving me some grief, but ya if you want the bin for your collection or just fun reading, i did read it off the chip and could send it. just let me know

MrWillys

Cliff is truly intelligent, and has the programming knack down. I took some classes years ago, and was real work for me. I can build a PC, and even write a little HTML. I prefer to use more user friendly front ends for tuning. Datamaster IMHO is way better than TunerPro for it's Histogram feature alone. Sadly, it is not available for 85's 6870 ECM. I use Tunercat for .bin editing, because it is easier than some of the free programs out there.

Tuning for me is ever evolving. Seems like every 6 months, or so I change and try things different. Currently, I'm running a pretty stock AXCR (speed density) file with modified VE table for my small cam, and elevation here at 5100'. Keep digging into it and have fun with it. Get a Moates adapter with a zif socket to make changing out chips easier. The ARAP file I posted is the best of the 7165 in my opinion. See my links page on my site linked to my username for more information on the subject matter.

Cliff is right about the 108 BLM count. The ECM is taking away as much fuel as possible. Why?

ladystoy69

hmm Histogram feature sounds interesting but as of right now i havent even played with alot of features in the tunerpro rt 5 , like somewhere i have seen where on a logging test drive it can fill in cells for later review but as of so far my experiance is just regular logging setting still lol

as for Moates adapter with a zif socket i already have that and some chips for the 165 ecm already, i'm just learning and playing a lil on the 870 atm till i get discusted and swap and yep i will be starting with that bin when i swap to the 165.

and as for the 108 blm i am not sure atm .. but yes the ecm is totally right it is very rich burns the eyes kinda rich .. as for why i am not sure at first i was thinking injectors leaking so i pulled them , cleaned them, tested them then put them on rail and pressurized like 20mins checking for leakage and there was non but there sure was when i pulled them so who knows they still could be giving issues so plan is replace hence why i was asking about the type III's and running 2 o-rings in another thread.

the other possibility could be the stooped cam in it, i think i will find it to be too big even with my planed future mods but idk... i have read that the durration of cams and ignition timing can give false readings to the ecm and cause rich conditions but thats a streatch as to being my problem i think but again idk

personally i'm liking the (blame hypertech) for it all after finding out there chip is in it lol nice to blame someone

MrWillys

I can't nail down the injector with the numbers you've provided. A Bosch number would be 280-150-947, but I get close with the Ford number as possibly a 30# red top. The 85 programming, unlike 86 and later has no direct assignment value for flowrate. It does have a gallon per hour table set to 3.81, or 22.3 / 5.85 = 3.81. If you could reset this to 30 / 5.85 = 5.13 it may solve this overly rich condition. However, it will still suffer from idle issue, because the ECM doesn't seem to function at a pulse width much below 2.

The spark table in a stock 85 bin should easily handle your cam. If you could add 2 more degrees at the 600 rpm range it would help, and add 50 rpm to the idle. I could build such a file for you, but I can't erase a 2732C chip.

As for the Hypertech, I've looked at their files and really wasn't impressed. They play with the spark table a bit, and modify the fan temps is about it. They coin cute little names like Stage II, and Thermomaster, and claim X HP increases. Bottomline, you won't get 40 more HP by adding a chip, and a K&N filter.

bjankuski

The 3.81 is constants is only used to effect your gas mileage readout, it is not used for fueling on the engine.

To change the fueling on an 1985 for different injectors you need to change the injector pulse width vs. load table. Scale the table by the change in injector size. Example (30-22.3)/22.3 = .3453 or 34% smaller to get an accurate starting point for the tune.

MrWillys

Interesting, thank you!

So, an example would be. injector pulse width VS load LV8 2nd line 16's value is 610 in an HLH BCC. 34% would be 610 X .66 = 402.6? And so on down the table?

bjankuski

That is correct.

MrWillys

Why the special formula if it is a % difference? Would part divided by the whole, or 22.3 / 30 = .743 be more represenative of a % multiplier?

bjankuski

Percent change of the smaller injector not the larger injector. In other words the change from the original to the new.

ladystoy69

mhmm very interesting but also very confusing to me, more i hear about this 870 ecm the more i dont like it. thank goodness for success burning my first chip with ****** base bin, it claims complet and success and i can read it with burner and looks right so lets hope its right.

i didnt stack bins or anything special as i dont really know how , i know the bin is a 16k bin(dont know how to tell size of a bin though) but not sure what size the 27sf512 chips im using are. i would assume 512k but i read lotsa strange stuff like 32k etc but i tried stacking as 32k and that didnt work, also no idea what to fill in for block size either.

is there a way to tell these things or are these things you just have to know? like 16k bin for tpi maf vs 32k for tpi sd etc etc or can these things and chip sizes be detected somehow?

bjankuski

The 1985 chip is 4kb, the 1986-1989 is 16kb, and the 1990-1991 are 32kb in size. This is all related to bytes not bits, multiply by 8 to get bits. The SF27512 chip is 64k bytes or 512 bits (64 x 8).

To stack on a 27sf512 chip (using the tunerpro stacking tool) you would enter bin size of 4kb, chip size 64kb, and block size 32kb. You need the G3 switching adapter from moates to use stacked bins and switch between them and I am not sure how you would do that with an 870 ECM since you cannot put a G3 in a 870 ECM. Maybe someone else can add some info on that subject?

MrWillys

When you burned your 128k file to your 27SF512k chip did you assign a Hexadecimal start address of C000? If you don't correctly address the burn it won't work. The burner will acknowledge it did the job, but the ECM won't find it.
I've never done any stacking, so I would just assume you assign different Hex address's and burn to different portions of the chip, so the Moates device can switch between them.

ladystoy69

i used buffer start 000000 chip start 00C000 chip end 00ffff as found on the moatws site but my pocket programmer shows these as
buffer start 00000 chip start 00C00 chip end 0ffff so im assuming it is correct.

i had just read that some stack the same bin to simplify and so there sure there will be no read problems, i dont really see how that simplifies though or stops any problems.. i do see a use though if using a switcher but otherwise nope idk but ok thanks

also thanks to bjankuski for all that info in one spot, i have printed for future referance as well. and as for the 870 ecm i am not real concerned with as im just trying to sort out non ecm running problems before 165 swap so atm just trying to learn and understand the data for tunning/programming etc but will be using the 165 soon . thanks