Emissions Got Me Frustrated

[joeairforce]

You have to get an HEI meant for an Oldsmobile. They have a different oil pump driveshaft than a chevy.

They also turn backwards from a chevy......

 

[azmalibuwagon]

There isnt a way to de-computerize my carb is there? Sounds silly i know but is it possible?

Yes, you can, but it isn't going to help with your idling problem, the computer doesn't control that.

To try it out - If you disconnect the Throttle Position Sensor (driver side front, in front of the accelerator pump), the carb will just run full rich. My car actually runs pretty good that way, just blows a bit of black smoke and kills the gas mileage. Don't forget to plug the connector back in after you test it out.

To permanently disconnect the computer, it's best just to get a non-electronic carb.

***

If you have a book store handy, run down and browse through Cliff Ruggles' book 'How to Rebuild and Modify Rochester Quadrajet Carburetors' and if you intend to take your carb apart, buy a copy. Nice big color photos. It covers the mechanics, but breezes past the electronics.

If you want to understand how the CCC and electronics work, then you need Doug Roe's book 'How to Rebuild and Modify Rochester Quadrajet Carburetors', considered the Q-Jet Bible by a lot of people. It goes through everything - even covers the AIR emissions system.

Either book will give you most of anything you need, but I found that the two together complement each other.

 

[DoubleV]

To try it out - If you disconnect the Throttle Position Sensor (driver side front, in front of the accelerator pump), the carb will just run full rich.

Disconnecting the TPS does not make the carb go full rich. Disconnecting the Mixture Control Solenoid on top of the carb does.

 

[azmalibuwagon]

To try it out - If you disconnect the Throttle Position Sensor (driver side front, in front of the accelerator pump), the carb will just run full rich.

Disconnecting the TPS does not make the carb go full rich. Disconnecting the Mixture Control Solenoid on top of the carb does.

😀

OK, I'll modify my statement - my carb runs full rich with the TPS disconnected. The computer doesn't have anything to tell it where the throttle is, so it just defaults to full rich. Yours may be different. 😀

 

[pencero]

same problems here I have older 307 w newer carb and emissions valve idling at 1500-2k and running dual flowmasters im following this thread to see what you come up with because I couldnt correct the problem and now the car is sitting, it drove alright but was accelerating pretty slow once the duals were on the car for a few months. Im anxious to see what you come up with

Id caution you that I paid alot to have the emissions equipment all set to factory / vaccuum lines reset&tagged and the egr valve corrected and 307 didnt like it at all dont make the same mistake as me and hook all that stuff back up - the engine ran much better with the emissions all unplugged and egr valve welded shut!

good luck

 

[RITTER]

Your best option has been mentioned many times. Get yourself a different carburetor, you can still use a factory quadrajet, but you need a NON CCC carburetor :!: Also, pick up a good used or brand new HEI distributor :idea:

You are NOT going to fix the issue with your CCC carburetor when your computer is not getting the correct signals.

 

[Bonnewagon]

When I backfitted my 3.8, 231 to non CCC it was an adventure tracking down the right carb and distributor. The distributor I found in a boneyard that stored them way upstairs in a huge shed in numbered bins. I think it was from a 79' Regal and it was the ONLY one within 50 miles. The carb I found locally in another boneyard with a carb shed, but I had to pore over all of them before I found one, a recently rebuilt Dualjet with Pontiac linkage (NOT all the same!). All that work and it was still a POS 3.8.

 

[RITTER]

Your best bet for a NON Computer Controlled Carburetor, would probably be from a mid to late 70's 305 Chevy engine. It should be jetted correctly for your 307 specs.

I guarantee if you try to put this engine back to the factory smog specs, you will end up spending close to a $1000 and you will still be dissappointed in the end with the lack of power. Do not make this mistake :!:

 

[sarends]

The choke could be the problem but whenever it was idling up i unhooked the little plug for the choke and it didnt change. I went around that choke thinking it being unhooked and not doing anything when i crank the car, must mean it wasnt the problem. Is there a diagram of how its supposed to be hooked up somewhere?

When is it 'ideling up' exactly? When does it go back down?

What plug on the choke are you refering to? Do you have an electric choke? Remember the choke is more than just the flapper on top of the car. It's a whole system that makes your engine rev higher when the choke is on. You definately have at least some choke issues since you say it's always open.

Do you still have that big goofy vacuum diaphram on the front drivers side of the carb? That thing kicks up your idle during certain situations. Just remove it if it's still there since you won't ( or aren't ) be running the proper gizmos to make it work right anyway.

Pics would help greatly.

It doesnt go back down till long after i leave the car alone for a while. Its acting fine now but who knows when it will pop back up again. Its an electric choke and its just not functioning. Also the diagphram you speak of has been capped off and is still there.

 

[DoubleV]

Your description of how your carb's behaving is still a bit vague. Walk us through EXACTLY what's going on from when you first start the car up in the morning to whenever it idles normal.

And when you do this, you need to provide us with what's going on with the choke during all this. I don't feel like typing out all the detailes, but in a nutshell;

When the car's stone cold in the morning and you pump the gas to get it started, the choke 'flapper' on top of the carb should snap shut immediately when you first pump the gas. If it doesn't do this, it ain't right.

Assuming it shuts like it's supposed to, after the car starts, the choke pull-off ( vacuum diaphram on from passenger side of carb ) will activate and open the choke flapper a little bit. If this isn't happening, it's not right.

When the car is running, it should be reving higher than normal due to the choke linkage behind the round choke housing keeping the throttle open more than normal. This is called 'fast idle'. You can adjust the fast idle with the fast idle screw on the bottom passenger side of carb under the choke housing. Note that there are multiple fast idle steps. So when you fist start the car, it may idle very high, but when you blip the throttle it will go to the next lower step and idle lower ( but still higher than your normal 'curb' idle ).

No matter how many times you blip the throttle, it will remain on fast idle untill the spring in the choke housing heats up enough to allow the linkage to get off of fast idle. This should take a few minutes. Once it heats up enough and you blip the throttle, you will be on normal idle which is adjusted by the curb idle screw on the drivers side of the carb ( probably hard to get to with that big stupid diaphragm thing in the way...which you need to remove ).

If your carb is not doing any of these things, it is not right. You need to find out exactly how your carb IS running now so we can get it to work the way it should.