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1983 Rivi Conv 307, 85k miles. One last chance before tossing this "New" CCC Carb (National Carb ND4469) into long term storage. Fully warmed up. The MC solenoid never stops clicking (dwelled at 32 degrees 6 cylinder setting), and the car will not idle it just dies. Unplug the MC and it idles fine with 21" of vacuum (steady). So don't think it's a vacuum leak, everything tight and plugged up. Tried a new O2 bosch putting out about 0.1v, the old denso closer to .75volts and no change when unplugging the new o2. Unplugging the old one the idle speed would change, so bosch going back. Map sensor tested it's fine. Did plugs and wires waiting for the new O2, plug wires dated 1982 bytheway and timing set at 22 degrees. I'm guessing that leaves wiring or the computer itself (maybe the carb). I doubt wiring because there are changes when things are unplugged and plugged back in. If you unplug the MC and let it idle for 10 mins, plug it back in no clicking till you touch the throttle. No exhaust backpressure, no stuck heatriser running rich with MC unplugged.
Once last thing yesterday it started idling way high (1500 rpm), so I lowered it. Today it was to low and very low on power when driving. Thanks for any input.
The solenoid is supposed to click constantly. That's how the CCC system controls mixture ratio. Have you followed the adjustment process in the CSM exactly? Are all hoses correctly connected and in good shape?
Throw away any and all Bosch sensors on a 307 CCC car. That's a generalization, but as a rule, you'll never beat the ACDelco sensors as far as operability consistency by using Bosch sensors. I've never had any luck with anything Bosch on a CCC Olds.
Update: Didn't mention that when I bought this, it had a normal qjet installed (new ccc carb in trunk) and ran like it was towing the titanic. This morning, disconnected the battery, re-installed old denso O2 (which tested ok but didn't know the history plus it was black from the old carb), fired it up running fair. Cranked up the idle a bit and it's running really well (23" vacuum). You can barely hear the MC clicking, yesterday I thought a lifter was going out it was so loud. So I'm thiniking it really just needed a computer reboot and a little more idle speed will have to hookup the meter and see where it's idling at. Will pickup an AC Delco o2 for backup and try another cold start see how it runs. Also check the spark plugs see if it's running rich or fairly normal. Thanks for the help.
Your O2 sensor was originally p/n 8990741, however the GM part number has changed about 400 times. It had changed previous to 1983, and certainly changed afterward. But the ACDelco part number you want would still be AFS-20. Superseded to AFS-21. Regardless of the GM part number. Already has the glass beaded stuff on the threads pre-lubed. Don't clean that off before installation.
Here's a "cheap" brand new old stock AFS-20 on ebay that will get you where you need to be. Well worth it to get GM/ACDelco O2 sensors, IMO.
It's a 4 wire CCC distributor. Little discovery , unpluged the 4 wires to check timeing and went for a road test (accidently). No difference in power with it unplugged or plugged in. And it does feel like there is no timing advance. I cranked up base timing to 25 degrees for giggles, no difference and no pinging either. By brother has an 84 delta 88 same motor and has to be 500lbs heavier and it's got more power. I think I'm going to check the wiring going to the distributor I can tell this motor got hot at one time, the MAP hose was melted in one spot. Maybe the module is bad. Probably should have done a compression test before doing the plugs. But anyways it's running pretty good right now, just down on power.
It's a 4 wire CCC distributor. Little discovery , unpluged the 4 wires to check timeing and went for a road test (accidently). No difference in power with it unplugged or plugged in. And it does feel like there is no timing advance. I cranked up base timing to 25 degrees for giggles, no difference and no pinging either. By brother has an 84 delta 88 same motor and has to be 500lbs heavier and it's got more power. I think I'm going to check the wiring going to the distributor I can tell this motor got hot at one time, the MAP hose was melted in one spot. Maybe the module is bad. Probably should have done a compression test before doing the plugs. But anyways it's running pretty good right now, just down on power.
The CCC distributor module has a "limp home" advance curve. It is based on RPM only, so basically what you would get from a mechanical advance only distributor. You can actually pull the plug on the ECU and the car will still run. It will be pig-rich and will run like crap, but it will run.
Any codes being thrown? If your distributor is not advancing electronically, there should be a code or two making that Check Engine Light (CEL) light up as you drive it.
One issue is the check engine light isn't working, so just testing everything I can with the 40 year old sears tester and a vom. Thinking they sell a pre obd1 blinkie tester...
Update 3 or so. Tested the advance, it's working. Had to paint the little timing groove on the damper, olds did not make it easy to see. That's the good news, bad news it idling bad again. So the MC is back to the loud clicking. Really leaning towards the carb running rich from the symtoms and reading the plugs. As soon as I unplug the MC it idles fine. I'm thinking the o2 is seeing rich and trying to compensate by telling the carb to go lean. Plus it won't restart unless you pump the pedal. I'm going to take the carb apart tomorrow and see what's doing. Pic of spark plug with 10 miles on it:
Pulling the plug on the M/C solenoid deactivates that solenoid. The springs under the primary metering rods push them all the way up, which runs the carb full rich on the primary side. Have you attempted to adjust the idle mixture screws using a dwellmeter, per the CSM process?
Just curious as to why you are going to all the trouble to make the CCC carb work. Do you need it functional to pass emissions testing or do you want it factory stock?
Just curious as to why you are going to all the trouble to make the CCC carb work. Do you need it functional to pass emissions testing or do you want it factory stock?
If it didn't come with a rebuilt carb, I would never and even tried to get the ccc going. Car wasn't running good when I got it, so figured I'd at least give it a try I did order a late 70's hei just in case, won't be here till friday. Plus it's my first ccc car that was original. Usually that stuff is long gone. If I dump the ccc, I'll box it all up and the next guy can give it a go. Only other thing the car needs is the back windows aren't working, and really not looking forward to that (got the chryler drive tape already). So I'll give it one more try today, still doesn't make sense how the MC can be messing up the idle don't see any fuel overflowing looking down the carb when it's running. Unless it has the ability to completely turn off all the fuel even at idle...
You don't need a scanner to read the codes, but you do to monitor the O2 voltage and also the "dwell" of the Mixture Control solenoid. If unfamiliar with this CCC system, you face a steep learning curve. If the O2 voltage is low, that would trigger a lean code and the MC sol would pulse less. Is your Check Engine Light on? It should be unless the bulb is missing or burned out. As Joe said the more pulsing there is, the more the ECM is trying to lean out the mix. You are going to need to get a GM Service Manual and really read it unless you can find a mechanic or maybe a mobile diagnostic person who understands the system.
I understand the basics of the system, a lot like a tbi in carb form. Unplugged the TPS and that stops the MC clicking and runs fine seems like the norm when you unplug something. Took the carb off to see what kind of bleed screws it has, should have done that before putting in on in the first place. They were only out 1-1/2 turns. Will have to read up on how to test the mc and tps. Found another site with a ccc rebuild, looks like fun. https://www.thirdgen.org/forums/carb...-ccc-qjet.html
Update. Let her get nice and warmed up, nice 80 plus degree day in lovely phoenix. Set the idle mixture screws to 3.5 turns out. Set the idle to 800rpm. Adjusted the tps to .479 volts, it was at .39 give or take. Used the inside of a red wire connector as a socket..Trying to adjust the MC to get 30 degrees dwell and she is super sensitive. But so far it's idling really well. Will see what happens on a cold start tomorrow, well kind of cold.
If you still have the MC duty cycle at 32 degrees on a six cylinder scale it's fine. Check the TPS voltage with the engine off, key in run, at idle position as you did (.5 DCV is the target, .479 is fine) and at full throttle, full throttle position should be approx. 4.5-5 DCV. The voltage transition from idle to full throttle should be smooth.
Keep at it you'll get it and learn at the same time.
Running the best it's has since I got it. Numbers, idle 650ish in gear ac on (no speedup solenoid), MC Dwell 33ish (meter reads 32 when mc is unplugged so close enuff), Idle mixture screws out 2.5 turns, MC out about 5 turns (noticed if the idle mixture screws are to far out, the MC is very sensitive), TPS 0.46v idle, 6v floored, need some bettter back phrobe pins. Runs strong from a dead stop, rolling slow and floor it, it won't downshift. Looks like the TV cable is streched out to the max, it's all the way back. Need to do the tranny fluid/filter soon. So just need to put some miles on her, see what happens. CCC fairly simple system, but everything has to be working and adjusted right. Thanks again for all the help.
Better get that TV cable situation right on the transmission. If your pressure is too low, you'll fry that puppy in short order. That's one of the drawbacks of a TH200-4R. So if you need a new cable, get one in there soon.
The Mixture Control solenoid should not be unplugged when reading the dwell. If you do, you may be reading the default strategy and not the real command. Pretty sure you will have to drop the pan to replace the TV cable, so good time to change filter and fluid.
Actually, you don't. It's easier if you drop the pan, but not mandatory.
True. I have done it without dropping the pan. PITA, but doable. CSM even says to do it this way. I reached in with a 90 degree O-ring pick and pulled up on the spring loaded actuating rod, and slipped the new cable end on there then bolted it in place. Make sure the seal is in place before getting in a hurry. Ask me how I know. Retainer bolt should be tightened to 84 INCH/POUNDS. Or in layman's terms- nice and snug.
But if you're going to change the filter and fluid anyway and doing it at the same time, doing it with the pan dropped is definitely way easier. Plus you can visually check the plunger is actuated all the way when doing TV adjustment.
Adjustment (per the 84 Olds Cutlass CSM):
Note: You do the full throttle opening rotation from under the hood. Not the gas pedal.
Last edited by 69HO43; February 3rd, 2021 at 02:45 PM.
Little rusty on 80''s gms but got the detent/tv cable figured out. Whoever installed the regular qjet modified the mounting point for the cable end. The mounting point was 1/2 back towards the firewall then where it should be. So got it hooked up right and adjusted. Had to take the egr valve off to get in there. Will take it for a drive tomorrow.
Another update for those following this CCC thread. Car is running I think about as good as it gets for being nearly 40 years old. Idles a bit high for my taste, but will live with it till I fell comfortable enuff to lower it. It's really goes strong from a roll up to 65mph, almost shocked me. I just ordered a new muffler and resonator with new pipes, whatever is on there now resonates like a flowmaster going at cruising speeds (no like). Now doing the trans fluid, not looking so good. I'm going to suck out a gallon, drive it a bit and see how it does and looks. Then filter this weekend. Might be the worst fluid I've seen (working on cars for 40 years now), but it's shifting fine, knock on wood...Oh my free pickle jar (1 gallon) and $8 vacuum pump from goodwill. Man goodwill was great about 10 years ago.
January 31st, 2021 | 05:52 PM
