what does the computer in my carbed car do?...can i modify the computer so it would preform better?

has anyone does this..

 

It controls emissions equipment and the timing advance on the HEI distributor. I don’t believe there are any hacs out for CCC computers.

 

The CCC computer controls ignition timing, TCC, and AIR. It also can influence but not completely control fuel, via the mixture solenoid in the CC Q-jet. IIRC, that's pretty much it.

It probably wouldn't be too hard to hack a CCC PROM but I doubt anyone really has much interest in doing that nowadays. Back in the '80s, there were people here and there who were messing with CCC chips, but they were few and far between. I've never seen anything in the public domain as far as a hac, or a how-to, either.

I thought about taking a stab at it a few years ago, but decided it'd be a much better use of my time to convert to TPI instead. I had the ol' Q-jet running pretty well, but EFI wins hands down for overall performance.

 

engine management. fuel/spark/idle control/ talks to you if it is ill.

 

Get a copy of the GM ZZZ engine retrofit kit instructions. In it gives the part nos for the best of the CCC ecms, prom, and secondary needles to use.

About the only decent easy to find secondary needles are in the 4 brl 4.1 CCC Buick engines.

Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly.

 

Coincidentally, I have a copy of those instructions handy.

The ECM supplied with the GM HO Conversion Kit is 1228079.
I've heard that ECM was OEM in the last of the L69 Montes. The PROMs used are 24502457 for the '82-'84 LG4 (no ESC), and 24502456 for the '83-'86 L69, and '85-'87 LG4 (which have ESC). The GM kit also includes a set of AH secondary metering rods; and the appropriate ESC module and knock sensor.

The parts list is also in the GMPP Catalog, or I can scan and email if anyone needs.

I put one of those ZZ4 conversion kits in my '83 T/A back in '98. Ran it for nearly five years in CCC trim, before changing over to EFI.

 

Just out of curiosity, what ecm was used for the carb computers? I assume it was probably something even more stone age then the C3s?

 

wow almost of all of that went right over my head...but thanks for the help....so bottom line is there anything i can do to improve the car by way of the computer besides just ripping it out?

 

good question. not sure what the puter carbed models ECM controls but i suspect it has a TPS sensor at the least. if ecu controls transmission that is another story. i see comment on knock sensor. that tells me ecu controls spark. i am sure there is a possibility running without ecu and go standard carb. do you have a manual trans?

 

yea manual trans

 

that makes it easier. no ecu control of trans. seems spark control may be it if you go carb. not sure what sensors it has. tps? map? coolant temp? do you have emishions testing?

 

IMO, don't be too quick to assume the computer is holding you back.

The timing curve that GM programmed for you may very well work better than what you'd get from a mechanical/vac distributor, especially if you do like 99% of the planet, and don't invest the time and effort into getting it curved correctly.

And the computer-controlled Q-jet, is really only computer-controlled at idle, and light cruise, via the idle mixture solenoid; when you stomp the go pedal, it's a mechanical carb again. People bad mouth Q-jets just because they don't know how to tune them. Read the Doug Roe book that Grumpy mentioned.

If you have aluminum heads, you might try the 1228079, with the ZZ4 PROM I mentioned. For iron heads, it's probably got too much timing.

Something you might find useful, is to get a laptop, and use it to monitor and record data via the ALDL port. Although the update rate of the old CCC computer is pretty slow compared to what most of us here use, it'll still provide useful info. You might also try WinALDL on that 1984 computer -- I couldn't get it to work with the 1228079 (datastream is different) -- but it is set up for some CCC systems. WinALDL is free, and you can build the necessary cable for a few bucks. Diacom does work with the 1228079; unfortunately it isn't free, but sometimes you'll see older versions of it for sale at reasonable prices.

If you really want to get deep into things, it probably wouldn't be that hard to find the spark timing table in the CCC PROM. Read the "getting started" article (2nd sticky down on the DIY PROM main page). Only difference, you'd be dealing with an old 2732 chip, and editing it with a hex editor. There's plenty of stuff on the internet about how the 1227747 TBI ECMs were hacked; the same methods would apply to the CCC ECM, except that it'd be even easier, since the ECM has less to do. While completely hacking the code might take awhile, the spark tables should be a recognizeable pattern that would be pretty easy to spot.

So, make it work for you. Or, if you'd rather not, all you need is a conventional distributor w/mech & vacuum advance, and the carb of your choice, and you're back to 1960 again. Either way will work, if done correctly.

FWIW, my CCC car was running 13.6's at about 102 mph, on 3.27 gears, and a stock GM converter, and it would get better than 22 mpg on the highway. While those numbers aren't anything special, they were a surprise to the people who'd told me I should get rid of all that "computer stuff."

 

It would definatly be interesting to see waht the entire source code looked like. One of the things I wondered about is waht ecm was actually used for them. Imagine that the hardware is different so getting at the onboard rom, assuming it does have it, would be difficult. Theres a neat algorithm out there that works on all C3 ecms but donno if anything could be adapted like that for the carb computers. Would be neat to see whats on them, though.

 

13.6's are very respectable...im not one to bad mouth the fuel system on my car and the carb will be one of the last things to go..im going to read up on this more..thanks for the help

 

Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-JetDoug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. s will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly. Doug Roe's, book about modifiing Q-Jets will tell you how to tweak the fuel, and linkage, properly.

The AH needles haven't been available for years.
The AVs, will work just fine. Also, the ones out of the 4 brl 4.1L v6 Buicks.
Get the ZZZ chip.
The CCC emcs, I'm sure used a 2716.
With the ZZZ and the afore mentioned book, you can run in the 13s. BTDT.
About the only real difference from the CCC to TBI is the CCC's have a float bowl. The CCC can be made to run as well as the best of the TBIs, except for fuel slosh in the float bowl.

 

whats a ZZZ chip?

and what does BTDT mean?

 

Whats the name of that book again?

 

Thats teh high performance chip for the carb cars. My friend has one with his zz4 and the car goes quite nicely.

 

I think there might have been a book, about Q-jets...


I'm thinking they found some, or had some more made. They're included with the ZZ4 HO Conversion kit. I didn't email Dal, but GM P/N 7033812 comes up on gmpartsdirect, current price is $45.

At that price, I think I'd try Grumpy's 4.1L ones first! Should have no problem finding those in junkyards!


ZZZ was the old GM RPO code for the HO 350 crate engine. Subsequent revisions were RPO ZZ1, ZZ2, ZZ3, and the current ZZ4. I guess you could count the ZZ430 as being in the family too.

The current HO Camaro Conversion Kit ships with a ZZ4. It's an emissions-legal upgrade for LG4 and L69 cars. The GM Performance Parts Catalog has the details.

I'm sure you are correct, so please excuse my previous brain fart.


(BTDT = Been There, Done That.)