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86 California Quadrajet running like poop - too rich?

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drftsub

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Hey guys,
Hopefully you can help me out with this.
I have an 86 blazer with a 350 and a computer controlled carb ( california ) .

I have a horrible rich problem that i cannot figure out , nor can I find much information about tuning the carb. As far as I can tell the carb should be stock inside, and I have tried the adjustments that I can find online but what I am still getting is a check engine light and a choke light that stay on constantly. If I rev the engine with quick throttle movement I get puffs of black smoke out the exhaust, and on warmup the truck pops and misfires as well.

Any suggestions or links to info on how to resolve this would be awesome, I have searched and cant seem to find what I need. I also have no idea what codes I have or the "poor mans" way to check what the current codes are, and where I can find what code means what.

thanks for any help ~!
 
Check the trouble codes first.

I don't know much about these systems, but I do know that if the ECM fails, the primaries default to full open, which means rich.

The setup MAY do the same thing if it detects other failures, but I can not say that with any certainty. Figure out what the code(s) are that it is throwing, and see where that leads you. Although GM codes are typically similar no matter TPI, TBI, or CCC, some are specific, so make sure whatever codes you look up, are done so for a CCC application.
 
Is the Choke Opening?? My old 80 Camaro had a similar problem, turned out the oil pressure sender,(which on that car sends power to the choke) was bad, teh choke never opened and it ran like Caca. New sender, dash lights went out and ran much better, at least as well as a 305 can run....
 
I agree I need to check the codes,is there a process I can follow to do it with out a code reader?

The choke is opening, although not all the way, but in my trouble shooting process I stock the choke full open and still had the same problems. Thanks for all the help guys!
 
As I recall, somehow that choke switch is tied into the choke light so that if there is no oil pressure, the light stays on. If your choke light is staying on, probably a good guess that the oil pressure switch is bad. Either open (connector on the switch unplugged) or shorted to ground should make the light go out.

As to code checking, try researching CCC (or computer controlled carb/carburetion, etc) on google, etc, see if you can come up with answers on checking it. The buick GN site might cover it, also someone over at thirdgen.org could probably answer your question.

It's likely the same procedure as TBI/TPI, but since it was the first real computer system GM used that worked, it could be different, and that potentially could cause problems trying that way.

Come to think of it, I wouldn't be surprised if (one of) the code(s) you are throwing is rich, because the choke isn't working right. If it doesn't open like it should, it would continue to run rich. You could clear the code(s) by pulling the fuse for the ECM for 10 seconds, then reinserting, and keep the choke open as you say you have. The code may not come back.
 
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Dude, good luck! I'm having a heck of a time trying to get my wife's truck to smog. Here, I only have to smog once. Then I can mount a gazillion CFM coffee can to the thing it if I want. Problem is that it did not come with the stock carb so I have to try to find one to rebuild for smog. No such beast 'round here. I've been told GM only manufactured that particular carb for about two years. To further complicate matters, the mixture control solenoid, which is where my particular problem is, has been discontinued. I can buy the blue top solenoid all day long, but that one operates at a lower ohm signal than the ECM sends out:doah: Hence my desperate plea for HELP that has thus far fallen on deaf ears.
 
well, I am doing more testing now so hopefully I can track it down soon. I have a 75 that I am in the process of a TBI swap in so as soon as that is done the 86 is getting sold.

For the discontinued parts , I believe there is a law out there that says that if it is discontinued you can get out of smog. I would call up the local smog referee and speak with them on it.



thanks for the help again.
 
GM manufactured the CCC carbs for 11 years, never heard of a difference on the MCS. You don't happen to have the GM part number for it do you? I know trucks could have CCC '85-86, but no clue if they used them earlier on trucks as my references don't go back further.

I've got an '80's Cutlass parts manual I could compare the MCS with my 1985-88 truck parts manual as well. I'd be surprised if it changed, it could be an early/late difference across the board. It certainly wouldn't make sense to use different components on the same system, which they are. Not saying they didn't, because you must have a reason to say that. :)
 
I had an 86 Chevy with non-ECM carb and had a stalling, stumbling issue. Mine had a electric choke and come to find out it was a blown fuse at the fuse panel. Replaced the fuse and it ran like normal.
 
well,
it turns out that the ground to the 02 sensor went bad ( broke ) and that was causing the full rich problem. I definitly appreciate the help though guys, it was random that I found it though.

Thanks again!!
 
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