distributor dramas my C3 recently recently imported to Australia from New York has fired and stopped dead for some weeks now, it is an 81 model Auto , I had an auto electrician look at her today ,he was getting nowhere until he stated he was unsure what the wires that came out of the lower section of the Distributor did so he unplugged them and
the motor now starts and runs well . What have we unplugged and what problem will I cause to happen

 

Rookie advice: Get a wiring diagram of your year/model and trace the unplugged engine harness wires. One of them could be broken or shorted...or the related sensor could be damaged. The new distributor itself could have an internal short in one of the wires

 

pics would help too

 

 

Thanks for your interest the Delco Remy dizzy is the original one that came with the car. I just went and started the car it runs quiet good the tacho works the engine light is on, while it was idleing I reconnected the pictured 4 wire plug and it stopped instantly I unplugged it and it started and ran fine, they are faided but the colours seem to be Yellow, red/white, Brown, Back thanks PAUL. The seatbelts seem not to lock up do they only work on a hard stop with the vehicle ??

 

PM @papawana for a wiring diagram, at least until your shop and assembly manuals arrive.
https://www.corvetteforum.com/forums...nyone-196.html

I can't cite a source, but I believe that some Corvette seat belts have pendulums in them, such that they only lock up under heavy braking (or an impact). I assume this is an inspection item for you?

 

thanks i will try them on a dry road and see if they lock its a bit hard to safely check but for rego they will want to check them

 

Ok, this is the CCC setup. Computer controlled idle, low load mixture and spark advance. The 4 wire plug disabled comp control and it went into limp mode. No or very little spark advance. Ditch the whole setup. That ecu probably bit the big one. Get an 80-older carb and an HEI distributor with vacuum and mech advance. Finding somebody in the US who can diagnose it is hard. It was a crappy system when new. Forced on carmaker to get cars emissions lower.

 

Thank you i hope to get it going ok with the current setup but your saying its in the limp home mode and could be very expensive to try and keep it genuine.

 

Yes you have a computer controlled carburetor and distributor. By unplugging the wires the computer no longer communicates with the engine. You can buy the 1981 factory manual for the car and go through the diagnostics. A rebuilt computer module is about $140.

 

1981 was a one year only setup........it had a primitive one year only PROM computer that ran timing for the distributor and the idle mixture control solenoid for the carb.
Every GM car in 1981 had this setup no matter what you bought......and when I was a kid my Dad used to make a killing deleting this sad system when they would go bad.....most did around the 50,000 mile point.......mostly G-body V-6 Monte Carlos, Regals, Cutlass, Grand Prix....
The good news is that it is relatively easy to get rid of this.......
https://www.rockauto.com/en/moreinfo...041118&jsn=542

The carb is a little tougher........since you are in Australia.......find a good core on E-Bay and have it refurbished......Lars here does excellent work but may be too far for you.
Another alternative is the /41654175 Holley Q-Jet replacement:
https://www.summitracing.com/parts/HLY-0-6210/

DO NOT buy a standard square bore carb and adapt it to the Q-Jet manifold.......it is NOT the way to go......a LOT of people will tell you this is ok but it is a terrible setup.
DO NOT buy a refurbished Q-Jet from an aftermarket rebuilder........there are many horror stories......

Jebby

 

thank you, your advice is well received and I have more to tell my mechanic by unpulgging the computer does that point only to the computer or could their be a simpler fault in the circuits, some people have said maybe a capacitor or power module breakdown. thanks aggaIn and happy new year.

 

Thank you for the information on my problem it does sound like the computer and if available in Aus it may be the first step I do know now why it was well priced in New York, thanks again .PAUL

 

Although the computer controlled feedback Q-Jet carb along with the distributor appeared with the Corvette for only the '81 model year, GM actually used the set-up in other Chevys and Buick, Cadilliac, Olds, Pontiac product lines until '88. It does not work bad when functioning correctly, although they did upgrade the computers in the later years.

Maybe your mechanic or who ever is doing the trouble shooting could ohm out the four wires to eliminate the variable of having a damaged/broken wire, before replacing the computer?

 

THANK YOU for your interest ,the motor runs sweet until I plug the 4 wire plug into the loom it kills the motor instantly so I am thinking it maybe a short to earth is their any part inside the dizzy that could cause the drama as I say it runs sweet untill you plug the 4 wire plug coming from the base of the dizzy into its other half and back into the loom. I have priced a new Carby and dizzy that would not need the computer, they suggest a new inlet manifold also thrir is apparently some sort of cross tube in the top of the motor needs to be blocked as it can cause a over heating problem. total price for the whole job about $3000 AUD or $1800 USD. As a gamble i might purchse a recoed computer and see if it fixes the problem before i spend a larger amount. thanks again I am listening if you have any thoughts. PAUL

 

welcome from another Ozzie.

where you based?

you might want to fill in your profile so people know where your from for when they make repair suggestions,
it's not as simple for us to run to the corner store for parts for these cars.

 

newcastle new south wales Australia

 

I personally would keep and maintain the CCC system. It's essentially a computer-controlled fuel metering system that works really well when maintained. Millions of cars were produced that had this system and I've owned several back in the 80s/90's. I owned a 1981 Caprice which I drove for 275,000 miles virtually trouble-free. There were a few maintenance things ...just like on newer cars, which I had to replace, but so what? It always ran like a top. The nice thing about the system is when it works properly it'll idle perfect all day every day. I always got good fuel economy with my CCC vehicles too. People who say the system is crap are uninformed are probably (sadly) going to scare you down the wrong path, and you'll end up with a much higher maintenance vehicle that'll run like an ole carb'd car. I've got a few carb's classics and a couple CCC cars and I'd take the CCC any day over the carb cars. They just start and run great more like a modern car (assuming things are maintained). That's why new EFI conversion systems are so popular.

I have a good friend who 'back in the day' never took the time to learn how to maintain the CCC system and pretty much damned every one he ever saw as a 'junk' system. At the time we both had GMs and he took his same year GM and deleted the CCC and computer stuff. Took him a while and cost a fair bit to convert. He 'converted' a lot of cars he bought. In every case he ended up with a lousy-idling car that generally ran like crap (IMO) and would have to 'tweak n tune' the carb and ignition about every 5000 miles, got crappy fuel economy too. Ironically, years ago he suddenly 'got into' EFI vehicles ...probably out of 'need' and he says looking back he spent a lot of time only to go backwards.

I go to the classic Jeep forums quite a bit ..and Ive said this before: It's really common guys who just bought a first-gen EFI jeep show up and can't get it to run right and out of the shute blame the computer ..that it's junk. They just threw $100 of new sensors at it and still can't get it to run right. About 90% of the time it's bad vacuum hoses, intake leaks (carb leaks in your case), or poor grounds/wire connections. We walk them through the problems, they find a vacuum leak or carbon'd up throttle body and then it runs great. It's almost NEVER the computer. The key to troublshooting just about ANY EFI system is to start with the basics first. Make sure the things that fail 90% of the time are in good working order. Even with modern vehicles.

While not up to the sophistication of a modern EFI system, it's essentially an electronic fuel management system, and great for it's day. Your engine will operate much better if you educate yourself and keep it running like it was I would advocate. A lot of your hoses are probably brittle as heck, and some sensors could probably use replacing. Those items are generally really cheap to buy now. The more stuff you start pulling off, you'll go backwards and be worse off I believe (trans lock-up etc). Plus a cleaner engine is lot better for the environment if that matters. The information is out there (and on Forums). You should buy this book:
https://www.ebay.com/itm/GM-Product-...oAAOSw3pVZ2lTB


P.S. Love Australia ...was there not that long ago!!
.

 

You can interface your CCC system with a cheap older scanner too (How COOL is that!). Just about any MT2500 would work (need the older 5-pin adapter). You can only see a few 'basics', but still. Truth is just about all the CCC system components can be measured with a basic ohm meter and dwell meter.

https://www.ebay.com/itm/Snap-On-MT2...sAAOSw7PNeQEO5

Or if you REALLY want to go vintage:
https://www.ebay.com/itm/OTC-system-...0AAOSw54NeHejj
(but I would definitely go with the snap-on!! over the OTC)
.

 

thank you for your well explained opinion, the car is of to a well sourced workshop today to see if the problem can be sorted while keeping the Carby /dizzy setup original a replacement ECU may be needed i will see how things go , I horrid fires are now out here in Aus but torrential rains have followed. I think we have damaged the world as we new it , keep up the good work, PAUL