GM's Computer Command Control (CCC)

[rfoll]

I recently bought a 1984 El Camino to replaced the one that got totaled a week ago. https://www.speed-talk.com/forum/viewtopic.ph ... iew=unread. It has 100,000 miles with a 305 and the feedback carb system. The TH200C trans is toast, no reverse and high gear. The engine appears to be sound, but it has a funny Idle. When up to temperature he idle rises and falls off repeatedly. It would be easy to just replace the carb and distributor, but there are many things controlled by the ECU. The speedometer has a speed sensor, and combined with the ECU, it is likely how the cruise control works. It also might play a part in the operation of the clutch in the converter. It would be nice to have both of these features functional. I have two 1979 lockup TH350c transmissions to play with, but I don't know if the current system will operate them. My friend that does transmissions for a living says he can rewire the 350C to lockup automatically without external hardware. Also, I have no experience at all with working on the CCC systems. I'm told they produce significant improvement in fuel economy when they are working properly. Any advice, thoughts, suggestions, or experiences with this stuff would be much appreciated. Thanks in advance, Rick

[Schurkey]

Things were becoming functional by '84. The first couple of years of CCC was typically unreliable.

I was a service advisor in a Chevy dealership in '84. We put in a mountain of mixture control solenoids and O2 sensors. Vapor canister purge valves were a common problem, and GM had a recall on some of them.

A TH 200 that has 100,000 miles on it has already been rebuilt once. They popped like clockwork at around 50K. The 200C might have been a bit more reliable. We had a steady stream of 700s going bad in '84. They were outright terrible. Most 200s got replaced with TH350s, so a 200C can be replaced with a 350C although that swap loses the deeper first gear of the 200. Not a big deal, but noticeable given the low power of those engines.

The catalytic converter will either be gone or defective. A monolithic replacement for the original "pellet"-type converter is STRONGLY recommended--and maybe the only choice now.

Mixture control solenoids are adjusted using the six-cylinder scale of a dwell meter; or a meter that reads duty cycle. Carb overhauls are not impossible, but they are more complex--all the issues of a Q-jet plus all the issues of CCC.

GET THE SERVICE MANUAL and get access to a scan tool for this vehicle. No service manual, no scan tool--you're just guessing.

Oh, yeah. The FIRST thing to remember about CCC is that it's piled on top of a relatively common, antique engine design. Before you go nuts dicking with the computer and sensors and such, make sure you have compression, a camshaft that still has usable lobes, decent cap/rotor/plug wires/plugs/pickup coil/ignition coil, timing chain not stretched-out, and all the other "normal" stuff.

[rfoll]

I read somewhere the 200C had some significant upgrades over the regular 200, whatever that means. The car has a 3.08 rear gear, and will eventually get the 2.73 and likely the 350 engine from the other car. The low first gear would be nice for towing, but that supposes those transmissions will stand up to towing service. My transmission friend doesn't have anything good to say about a transmission with any 200 in the model description. I do have a code reader, but I haven't been there yet. It might be my best plan would to use the older equipment to get it on the road and do my research on the stock equipment when I have more time. I was getting outstanding fuel economy on the other car, so the smaller motor should do as well even in stock form. It appears to have good even compression and runs smoothly under load. Someone did some exhaust work, with an aftermarket cat and a Flowmaster 1 in 2 out muffler behind the rear axle. I don't know if that kind of stuff will an affect on the CCC. I'm curious how much of the electronics I can remove and still have a functional cruise control.

[Tuner]

The CCC is an ideal system to use with a WBO2 like an Innovate LC-2 controller or MTX-L WBO2 A/F gauge in place of the narrow-band O2 sensor to provide the feedback signal but at whatever A/F the engine gives the least fuel consumption at part-throttle. In feedback mode the NB system oscillates the A/F in a fairly wide range on both lean and rich sides of stoichiometric, resulting in approximately half of firing cycles are much richer than give best mileage. The Innovate devices have a programmable analog voltage output that can be set to provide the same voltage oscillations the CCC expects to see from the NB sensor - so it won't set the Check Engine light - and you can set it to do this in a narrower and leaner A/F range, such as 16.5 to 17/1, where the mileage and driveability will be a lot better than 13 to 17 with half the firing cycles wasting fuel. The CCC and the early OBD1 TBI systems control feedback well but are not sophisticated enough to detect they are being lied to. Using the programmable feedback from the WBO2 to control the electronic QJet gives you the best of both worlds, combining the excellent fuel vaporization of the QJet with electronic A/F control.

[novadude]

I’ve always wondered why nobody ever made an aftermarket CCC controller for feedback q-jets. Seems like it would be the ideal street machine carb.

[rfoll]

The CCC is an ideal system to use with a WBO2 like an Innovate LC-2 controller or MTX-L WBO2 A/F gauge in place of the narrow-band O2 sensor to provide the feedback signal but at whatever A/F the engine gives the least fuel consumption at part-throttle. In feedback mode the NB system oscillates the A/F in a fairly wide range on both lean and rich sides of stoichiometric, resulting in approximately half of firing cycles are much richer than give best mileage. The Innovate devices have a programmable analog voltage output that can be set to provide the same voltage oscillations the CCC expects to see from the NB sensor - so it won't set the Check Engine light - and you can set it to do this in a narrower and leaner A/F range, such as 16.5 to 17/1, where the mileage and driveability will be a lot better than 13 to 17 with half the firing cycles wasting fuel. The CCC and the early OBD1 TBI systems control feedback well but are not sophisticated enough to detect they are being lied to. Using the programmable feedback from the WBO2 to control the electronic QJet gives you the best of both worlds, combining the excellent fuel vaporization of the QJet with electronic A/F control.

How do you control the controller? I have an Innovate Lm2, currently hooked up in the race car to monitor fuel ratios.

[Tuner]

The CCC is an ideal system to use with a WBO2 like an Innovate LC-2 controller or MTX-L WBO2 A/F gauge in place of the narrow-band O2 sensor to provide the feedback signal but at whatever A/F the engine gives the least fuel consumption at part-throttle. In feedback mode the NB system oscillates the A/F in a fairly wide range on both lean and rich sides of stoichiometric, resulting in approximately half of firing cycles are much richer than give best mileage. The Innovate devices have a programmable analog voltage output that can be set to provide the same voltage oscillations the CCC expects to see from the NB sensor - so it won't set the Check Engine light - and you can set it to do this in a narrower and leaner A/F range, such as 16.5 to 17/1, where the mileage and driveability will be a lot better than 13 to 17 with half the firing cycles wasting fuel. The CCC and the early OBD1 TBI systems control feedback well but are not sophisticated enough to detect they are being lied to. Using the programmable feedback from the WBO2 to control the electronic QJet gives you the best of both worlds, combining the excellent fuel vaporization of the QJet with electronic A/F control.

How do you control the controller? I have an Innovate Lm2, currently hooked up in the race car to monitor fuel ratios.

Refer to pages 7 & 8, sections 5.3 & 5.3.1 in these instructions. https://www.innovatemotorsports.com/sup ... Manual.pdf Make sure the black ground wire for the LC-2 is connected to the same ground source as the ECU, or at least be sure there is no voltage offset between wherever each is grounded. Ground is not always exactly "ground".

With the LC-2 you mimic the voltage swings of the NB sensor by setting the analog output voltage to rich and lean limits straddling the desired A/F, with the target number in the center of a roughly 1/2 ratio range.

You can set richer or leaner A/F values than these in this example as your situation dictates, but this should work to get you started. Set a rich limit of 16.3 at .9V and a lean limit of 16.7 at .1V with a delay of 1/12 sec. The ECU thinks all is normal and it will control the engine to run at the LC-2's programmed average, which is 16.5/1 (or whatever AFR you choose).

[BillK]

R,
The 307 Olds engine in my Wife's 84 Riviera has the CCC system and it has worked fine for 230K miles since new I went through the engine and trans last year and redid all of the vacuum lines etc. I switched hers over to a hydraulic roller cam when I did the engine. It is just barely larger than stock and I used an Edelbrock performer manifold due to lifter clearance. Neither has seemed to affect the performance at all. I have done the carb twice over the years just for normal gaskets drying out etc. They are not that hard to do compared to a regular Q-jet. There is a couple of special tools you need to set them up but if you take careful measurements as you disassemble it you don't really need the tools.

Just be careful taking things apart. Some of the sensors are getting hard to find. I broke the top off one of the temp sensors and had to do a lot of E-bay searching before finally finding one.

[rebelrouser]

I also worked at a Chevy dealer when these were what we worked on. I still have the gauges and special tools to correctly do these carbs. The solenoid controls the fuel by pulsing the metering rods, that is why you set them with a dwell meter, but the amount of travel of the solenoid needs to be bench set with the proper gauging tools. As mentioned they did not work very well when new. I would spring for a throttle body EFI system. You may even be able to buy one that will work your lockup and speedo if you ask around.

[rfoll]

I suspect the carb is a rebuilt unit. It looks to clean to be 34 years old. The car had a smog pump, long since removed. I found 3 plugs on the passenger side that have been disconnected. I will have to look and see if they have a place to re-connect. At this point I am mostly concerned with getting a functional transmission in the car.

[barnym17]

Its been a long time but to the best of my memory the ccc system didn't control the trans back then. The most it would have controlled would be converter lockup.Which can be done easily with a vacuum switch.

[NewbVetteGuy]

The CCC is an ideal system to use with a WBO2 like an Innovate LC-2 controller or MTX-L WBO2 A/F gauge in place of the narrow-band O2 sensor to provide the feedback signal but at whatever A/F the engine gives the least fuel consumption at part-throttle. In feedback mode the NB system oscillates the A/F in a fairly wide range on both lean and rich sides of stoichiometric, resulting in approximately half of firing cycles are much richer than give best mileage. The Innovate devices have a programmable analog voltage output that can be set to provide the same voltage oscillations the CCC expects to see from the NB sensor - so it won't set the Check Engine light - and you can set it to do this in a narrower and leaner A/F range, such as 16.5 to 17/1, where the mileage and driveability will be a lot better than 13 to 17 with half the firing cycles wasting fuel. The CCC and the early OBD1 TBI systems control feedback well but are not sophisticated enough to detect they are being lied to. Using the programmable feedback from the WBO2 to control the electronic QJet gives you the best of both worlds, combining the excellent fuel vaporization of the QJet with electronic A/F control.

How do you control the controller? I have an Innovate Lm2, currently hooked up in the race car to monitor fuel ratios.

Refer to pages 7 & 8, sections 5.3 & 5.3.1 in these instructions. https://www.innovatemotorsports.com/sup ... Manual.pdf Make sure the black ground wire for the LC-2 is connected to the same ground source as the ECU, or at least be sure there is no voltage offset between wherever each is grounded. Ground is not always exactly "ground".

With the LC-2 you mimic the voltage swings of the NB sensor by setting the analog output voltage to rich and lean limits straddling the desired A/F, with the target number in the center of a roughly 1/2 ratio range.

You can set richer or leaner A/F values than these in this example as your situation dictates, but this should work to get you started. Set a rich limit of 16.3 at .9V and a lean limit of 16.7 at .1V with a delay of 1/12 sec. The ECU thinks all is normal and it will control the engine to run at the LC-2's programmed average, which is 16.5/1 (or whatever AFR you choose).

WOW! This is an amazingly impressive post.

Like a poor man's EFI system using an old CCC QJet.

Seriously, cool-as-hell.

Adam

[rfoll]

I plugged a code reader in today and got no codes, but then none of the lights on that panel seem to be working. I have some factory manuals coming to help me chase the system. The electrical service manuals I have used are quite helpful. No rush here, may transmission has no reverse or high gear.

[barnym17]

It was about as close as you could get to fuel injection for mileage and emissions, in fact it allowed GM to stay carbed after other oems had to go throttle body.The mixture solenoid in the primaries opened and closed (it was a metering rod setup) If I remember correctly x number of times per second You used a dwell meter to check operation. When the ccc system detected the mixture needed richened the rods stayed longer in the up or open position. Leaner was the opposite, plus you could tweak it by adjusting the metering rod height which was the open or full rich position.
I used to use these carbs without the ccc control for fuel mileage builds the metering rod height was easily adjusted externally I would just keep lowering the metering rod height until lean stumble at cruise then raise them slightly and you could usually pick up a mpg or 2.

[barnym17]

I could see where if someone wanted to with todays tech using the stock tps and mixture control ran by something like a megasquirt system could be really effective,using a wideband o2 sensor and much faster processing speeds of newer pcms it could really be tuned for perfect afr cruising down the road.And since the secondaries were not controlled in any way mixture wise they could be tuned for max power not affecting cruising economy.