Off idle BOG at WOT

[MonteLS_84]

I'm not quite following...are you using the CCC or not using it???

Not sure what ccc means. I'm running an hei distributor, and the car's module has been unplugged.

 

[stew86MCSS396]

From another forum...

Dumbest question of the night but what does CCC stand for? I should asked earlier but figured I could find it on google but just can’t.

Although I'm absolutely of very little help with Monte Carlo specifics, the real answer to your question is GM's CCC = Computer Command Control. It's also known as OBD1 (on-board diagnostics, first gen) to some mechanics.

It's the entire system, not just the carb. Some vehicles didn't even have a carb with the CCC systems. It was constantly updated since its advent of the 1981 model year and the goal was fuel efficiency and emissions reductions. This meant power was NOT even in the equation at first. They weren't able to start figuring all that out by a wide margin until the late 80s, when the G-bodies, unfortunately, were already slated for extinction. I believe the only cars that even tried to move quick by mid-80s standards were the turbo buicks, corvettes, and then later the Iroc-Z. They had to figure out a way to back-fit the computer controls onto the old-style engines.

The sensors all have to work together for the engine to run at its peak efficiency within the parameters of the system. Very crude 1st generation computer systems, but it was one of the grandfathers of what we have today with computers sensing/controlling everything in the car darn near. Vacuum leaks and bad sensors will make your car run like crap in a hurry. And hardly anyone knows how to work on them anymore.

Read all about the "new" 1981 CCC system debut here.

https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/Innovation_and_Technology/GM-Introduces-CCC.pdf

Sent the car to a shop and had a lot of work done (see attached image for specs). Upon getting the car back - still had the same bog. Note - went from the original Rochester carb to an eddy 650 at this point. Running original distributor (ECM controlled) with msd cap and coil.

I'm assuming here that the original carb is ECM controlled as well as distributor. Then you said you swapped a eddy 650 which I'm assuming is not ECM controlled but raises the question of how does that work with a ECM controlled distributor???

Bought a brand new Eddy 650 carb - still bogging.

At this point eddy swapped for eddy but still using the ECM controlled distributor???

Swapped in a freshly rebuilt 350, bored 40 over. Used all parts from "old" motor. Note - never verified what cam was in this new engine. Mystery cam.

Replaced the distributor with a GM HEI, using MSD cap and rotor - still bogging.

Swapped in a GM HEI which doesn't mean squat to me because my '90 C4 running a TPI engine has a GM HEI but all still being ECM controlled. Did you mean you swapped in a GM HEI with mechanical and vacuum advance???

Returned the 'new' carb and put the old one back on.

Okay I get it, new eddy replace with old eddy.

...but at this point, I still don't know if you're trying to run this with the ECM control or not or whether you're using ECM controlled components with components that don't.

 

[Wageslave]

To clarify - it should read 12 volts when key is on?

Measure it while the key is in the RUN position. The voltage should be very close to the battery voltage.

 

[78Delta88]

Try this...

RESOURCE - GM CCC service videos.

Found these professional CCC service training videos posted on Youtube. They explain the basics of the CCC ( 3C ) system and how to service it.

gbodyforum.com

https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/Innovation_and_Technology/GM-Introduces-CCC.pdf

https://www.autozone.com/repairguides/GM-Camaro-1982-1992-Repair-Guide/ELECTRONIC-ENGINE-CONTROLS/Computer-Command-Control-CCC-System/_/P-0996b43f8038674c

C3 or CCC = Computer Command Control

EST = Electronic Spark Timing = the module in the HEI that communicates with the ECM.

ECM = Engine Control Module. AKA (Also Known As): the "Computer".

You can not run the car with the C3/EST HEI by its self. It will not run right.

 

[78Delta88]

Basically what you need to do is baseline the engine.

Your CR Static for a 305 HO of that year is 9.5 to 1. CR static for a non-HO is around 8.6:1 just as an example. So you can see how just that one piece if info really changes things.

You need to know your cam Lift/Duration and LSA and your actual Static CR (Compression Ratio). From there calculate your Dynamic CR, needs to be around 7.5.

Sounds like you have a good street setup, +40, 64CC, 2.02/1.60. The 1.6 is good for scavenging which is a major SBC issue.

1.5 Ratio Rockers?

Do you know if; Domes, Flat tops or Dish?

Your setup with:
1/8 dome will get you around 10.5:1.
Flat Top 4 Relief about 10:1.
Common rebuilder dish will get you about high 8's to about 9:1.

If you can get car to idle just above the point it wants to die... What is its baseline manifold vacuum.?

 

[MonteLS_84]

From another forum...



I'm assuming here that the original carb is ECM controlled as well as distributor. Then you said you swapped a eddy 650 which I'm assuming is not ECM controlled but raises the question of how does that work with a ECM controlled distributor???

At this point eddy swapped for eddy but still using the ECM controlled distributor???

Swapped in a GM HEI which doesn't mean squat to me because my '90 C4 running a TPI engine has a GM HEI but all still being ECM controlled. Did you mean you swapped in a GM HEI with mechanical and vacuum advance???

Okay I get it, new eddy replace with old eddy.

...but at this point, I still don't know if you're trying to run this with the ECM control or not or whether you're using ECM controlled components with components that don't.

ECM was unplugged when I swapped distributors.

 

[MonteLS_84]

Try this...

RESOURCE - GM CCC service videos.

Found these professional CCC service training videos posted on Youtube. They explain the basics of the CCC ( 3C ) system and how to service it.

gbodyforum.com

https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/Innovation_and_Technology/GM-Introduces-CCC.pdf

https://www.autozone.com/repairguides/GM-Camaro-1982-1992-Repair-Guide/ELECTRONIC-ENGINE-CONTROLS/Computer-Command-Control-CCC-System/_/P-0996b43f8038674c

C3 or CCC = Computer Command Control

EST = Electronic Spark Timing = the module in the HEI that communicates with the ECM.

ECM = Engine Control Module. AKA (Also Known As): the "Computer".

You can not run the car with the C3/EST HEI by its self. It will not run right.

Ecm is unplugged. Does that solve what you're pointing to?

 

[MonteLS_84]

Basically what you need to do is baseline the engine.

Your CR Static for a 305 HO of that year is 9.5 to 1. CR static for a non-HO is around 8.6:1 just as an example. So you can see how just that one piece if info really changes things.

You need to know your cam Lift/Duration and LSA and your actual Static CR (Compression Ratio). From there calculate your Dynamic CR, needs to be around 7.5.

Sounds like you have a good street setup, +40, 64CC, 2.02/1.60. The 1.6 is good for scavenging which is a major SBC issue.

1.5 Ratio Rockers?

Do you know if; Domes, Flat tops or Dish?

Your setup with:
1/8 dome will get you around 10.5:1.
Flat Top 4 Relief about 10:1.
Common rebuilder dish will get you about high 8's to about 9:1.

If you can get car to idle just above the point it wants to die... What is its baseline manifold vacuum.?

The pistons were flat with the 1 (or 2?) dimple(s) on them. I'm assuming standard pistons.

Car can idle, run fine...revs fine without load. Heck, if I feather it enough, she screams past 100mph. It's just when I come to a stop and punch it...it falls on its face, or stalls.

Going to put a roller cam in, since I don't know what this cam is. Not going to try to figure out what it is.

 

[olskool]

Investigating the tank, fuel filters, pump will be my next plan of attack. A couple of weeks ago I completely ran out of gas (I understand there could have stoll been some gas or water in the tank), and filled it with premium and racing fuel mix. I'd think that would've put me in a better position if there were water in the tank...but I'll still check.

Seems like it would run goofy at other times but...I'm trying all suggestions.

if the fuel filter was stopped up it will act like it has no power and sort of bog, but water in the tank it will usually rev good sitting still, that when it gets a load it will bog and even shut off. then start up like nothing is wrong and do it all over again. and nothing, no additive i know of will get it out, you have to dump the tank,,,,,,,,,,,,,,,,

 

[78Delta88]

if the fuel filter was stopped up it will act like it has no power and sort of bog, but water in the tank it will usually rev good sitting still, that when it gets a load it will bog and even shut off. then start up like nothing is wrong and do it all over again. and nothing, no additive i know of will get it out, you have to dump the tank,,,,,,,,,,,,,,,,

Basically any alcohol will grab water. Heet (TM) is methanol, (or used to be), will work fine.

If you think you have bad fuel or bad supply.

1. Disconnect distributor... No spark
2. Disconnect fuel line going to carb
3. Add tight fitting tube, rubber/vinyl line to fuel line.
4. Put other end of tube/line into 1 quart or larger jar, 2 liter bottle or something about that size.
5. Crank engine about 5 seconds
6. Look at fuel deposited in the jar/bottle
A. Should be good amount
B. Should be clean
C. Should be free of water and dirt