K. I've searched for better than an hour.

Is there any available editing software for '81 CCC systems? I know that TC doesn't support it. Ever stumble across something that works?

 

Get the GM ZZZ retrofit book, and run one of the combs of ecm, esc, prom, mentioned in there.

They use a 2716 chip, but I know of no editors.

For tuning get Doug Roes Q-Jet book, the key is the secondaries.
At one time, I'd bought and tried every chip available for the CCC LG4, L69s, and the GM one in the manual was the best.

 

Grump.

Thanks for the info. I;ve gone through the rods, hanger, and windup tweaking on the E4ME. TPS and MC are right on. I'd just like to be able to have a little control over the TCC and spark curve. These things are probably so stupid-simple that a hack might revela something. I may just dump the PROM and analyze it.

BTW - It's a 1981 L81, kinda like an 'F' car....

 

If your really serious about this, and get some of the code figured out holler, and I'll see if I can hunt up some 2716s. I had some years ago so no guessing where Doc hid em.

 

You could also check with the guys at g-body.org see if they've got anything.

 

rhuarc,

Thanks for the heads-up on G-Body.org.

Grump,

If I find anything definitive, I'll let you know and FTP whatever I find that might be useful to diy-efi.org

 

Are you talking about the "Compucarb" cars? I have a friend with an 83 El Camino with a Computer controlled Carb and we wanted to change the spark tables and what not. Please post any information you get.

I pulled the chip out because I wanted to get the bin off it and the PPII doesn't support the chip.

 

Never seen or heard of anyone doing PROMs for 'em. Can't hurt to look around.

You could always swap to a mechnical distributor, just need to run a tach signal for reference pulses and such. ECM doesn't really know if it has control of the spark anyway.

Or convert a TBI ECM to run the distributor standalone with a MAP signal.

 

If a person wants complete control of the spark, then running a "stripped down" TBI or $8D bin (depends on which a person is more comfortable working with) could both be made to work well.

The $8D does allow you to modify the spark curve at higher rpm levels. But in all honesty, I generally get all my spark dialed in by 3,600 rpm; which is the limit of the TBI bin (as I recall). But there is even a patch code to extend the TBI's spark table beyond 3,600 rpm as I recall. Talk to RBob on that if you can't find the post.

 

Glenn,

Thanks for the reply. Good to see you in here.

I was hoping to use the original controller for various reasons. Unfortunately, it is unlike even some of the older TBI and CCC ECMs I have in a big ol' junk box. This one (a 1981 vintage) used a five pin ALDL, very limited I/O, and I'm sure had very liminted addressing capability.

I was hoping to crack into it to be able to open some doors for the large number of '80-'81 Corvettes that still use it. The controler is behind the left seat in the battery compartment, so rewiring would require a long, custom harness - a project beyond the willpower and patience of many owners.

Just a few more days, eh? Got plenty of digital film ready? (Inside joke) - Pun intended.

We hope to see more of you around here soon.

 

I'll see if I can get a copy and post a pic on the Tech Board for you.

 

An '82 or newer car should have the later PCM (12-pin ALDL, 160 baud, etc.)

 

.

 

Actually I've been able to read CCC chips - I had to make an adapter (I'll have to dig it out) and read it as a 2532a, but it worked like a champ. I've used the same trick with some of the C3 ECM's.

 

OMIGOSH! I would love to be able to do something with the timing and stuff on my CC carb ECM!

If I was to go to a TBI or other ECM, would there be a way to get a M/C solenoid output from it? Hmmm..... I would like to go to a better ECM, and a 730 would be ideal, as that's what I'll end up with once I get EFI on it, but not sure what to do with the M/C solenoid. I have no CAT to please anymore either. I would just go to a non CC carb, but it would be nice to keep the TPS to avoid running wiring, and modifying things to get a TPS signal.

Oh well, more thinking out loud, but if anyone has ideas, let me know!

 

I don't think the M/C solenoid and TBI/TPI injectors are compatibile electrically. At least that's what I've been told.

I think you might find it easier to read in the current PROM, then kinda "look" for table-like stuff and modify things from there. Kinda cheezy, but it's all I can offer without having to totally read in the code from the ECM itself. (Although I think I may have an option for that, too.)

Too bad I don't have an ECM bench, I could probably figure out some of the tables!

 

I've since been able to determine that the '81 ECM I've been playing with is plug-compatible with the 1227169 ECMs in later ('84-87) 'F' cars, right down to the wire colors. Now If I can just read the '169 ROM (are we sure it's a 2532?) I may have a real chance. I've read the binary files from a couple of spare '169s, and am trying to deduce the addresses now.

I haven't given up yet...

 

No, like I said, I had made an adapter so it would read as a 2532A. A couple of the pins had to be grounded (and not stuck in the programmer.) You wind up with 1k of data in the 4th quadrant of the chip.

Here's a pic of my adapter:



The chips aren't 2716's that I'm aware of, but the N82S181's that the early TBI ECM's used. They are 1k PROM's, and not EPROM's. This adapter allowed me to "fool" the programmer into thinking it was a 2532A (4k EPROM) and it read the data in.

 

Ken,

Thanks for the info. That explains my trouble reading several of the BINs. (Incidentally, I've got the same ZIF socket!).

I realized they are PROMs, not UV- or EEPROMS. The lack of a window and P/N was a big clue.
Guess it's time I dug out the pinout guides and started jumping. I'm going to have fun trying to find blank replacements - I can see it now...

BTW - It looks like the 1227169 uses the same ROM.