Adjusting the idle on 4 barrel 400 engine in my 1966 VIP (changed out of course)

[rsh1966vip]

I posted this question yesterday, but now I do not see the post anywhere , so I will re-post it.
I posted a picture of the two idle screws and asked for advice on making adjustments. I was asked to post pics of both sides of the carb. One thing happened when I lifted up the air cleaner to get the pics. The engine started to run rough like a plug wire had been pulled off. I took the pics shut off the engine, replace the air cleaner and re-started the engine and it ran fine. I must have pinched a vacuum line?? Anyway here are the pics:
thanks
rsh1966vip

 

[rsh1966vip]

More pics of carb, rsh66vip

 

[65Port]

I would try and replicate that rough running issue before it turns into a problem out on the road. As far as the idle adjustment, do you have a tach to see what rpm's it is at? Is the idle too high or low? I know someone pointed out the fast idle screw in the other post. That will be for when the engine is cold however.

 

[CBODY67]

On the driver's side front corner of the baseplate is a vacuum tap. Something should be hooked up there, as a commenter noted in the original thread. If not, that might be the cause of the whole situation? Where is the vac advance vac line?

GM-style "kickdown" cable?

Take care,
CBODY67

 

[57fury440]

As CBODY67 mentioned, where is the vacuum advance connected to? You have an open vacuum port which may be where it should go. It could also be making it idle rough. If that is not for the vacuum advance, then plug it so you do not have a vacuum leak. To raise the idle the screw turns clockwise.

 

[Toolmanmike]

I posted this question yesterday, but now I do not see the post anywhere , so I will re-post it.
I posted a picture of the two idle screws and asked for advice on making adjustments. I was asked to post pics of both sides of the carb. One thing happened when I lifted up the air cleaner to get the pics. The engine started to run rough like a plug wire had been pulled off. I took the pics shut off the engine, replace the air cleaner and re-started the engine and it ran fine. I must have pinched a vacuum line?? Anyway here are the pics:
thanks
rsh1966vip

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Now you have 2 threads on the same subject. Here's your other one. Advice on adjusting the idle 1966 vip with a 400 in it

 

[michiganhotrod1]

Fix that open vacume port, idle adjustment is hopeless while is is there.
Mark

 

[rsh1966vip]

Do you mean cap it? Maybe you can send me a pic of you carb showing the fix?? I am not a carb guy and sometimes people disconnect things without known the consequences. This is the way my (Chry mechanic
) mechanic did it. Let me know your commend preferably with a pic. I do best when I can see what we are talking about.
thanks
Richard

 

[Toolmanmike]

Do you mean cap it? Maybe you can send me a pic of you carb showing the fix?? I am not a carb guy and sometimes people disconnect things without known the consequences. This is the way my (Chry mechanic
) mechanic did it. Let me know your commend preferably with a pic. I do best when I can see what we are talking about.
thanks
Richard

Cap it if you don't have anything to plug into it. It looks like it is below the throttle plates so it should be constant vacuum. It will be a constant vacuum leak. What is your distributor vacuum advance plugged into?

 

[thethee]

Would a '66 have a temp sensor in the air cleaner housing? Pulling up the air cleaner and accidentally disconnecting that vacuum line, would that be enough of a vacuum leak to cause the rough running?

 

[Toolmanmike]

Would a '66 have a temp sensor in the air cleaner housing? Pulling up the air cleaner and accidentally disconnecting that vacuum line, would that be enough of a vacuum leak to cause the rough running?

66 shouldn't have a sensor in the air cleaner. Yes, a vacuum leak can very well cause rough running especially at idle.

 

[Toolmanmike]

Would a '66 have a temp sensor in the air cleaner housing? Pulling up the air cleaner and accidentally disconnecting that vacuum line, would that be enough of a vacuum leak to cause the rough running?

If you don't have any rubber plugs, A piece of vacuum hose and a screw or a golf tee will be a temporary plug. Parts stores usually stock these plugs. Performance Tool W5232 Performance Tool Vacuum Cap Kits | Summit Racing

 

[57fury440]

You have to plug any open and unused vacuum ports, or you will get a rough idle.

 

[CBODY67]

Those vacuum caps/plugs might also be in the HELP! rack at local auto supplies. In a variety of sizes. NOT expensive, either, but very helpful.

You can tell the person at the counter that you need some "vacuum caps" and they should know what you mean. For explanation, you have a vac port on a carburetor that needs to be capped off.

CBODY67

 

[57fury440]

Looking at your pictures it appears you have more than one open vacuum port.

 

[Toolmanmike]

Looking at your pictures it appears you have more than one open vacuum port.

I just see 1 other than the egr

 

[rsh1966vip]

I will get some vacuum caps this week and cap the two open lines. Thanks for all the comments.
Richard

 

[Big_John]

I will get some vacuum caps this week and cap the two open lines. Thanks for all the comments.
Richard

I only see one open vacuum line on that carb. The small one with the red arrow does need to be plugged. Actually, I'm pretty sure that one is the line for the distributor advance and I don't see any vacuum line for that... I don't know what the combo is, but generally speaking, a stock engine will run better with that vacuum line connected to the distributor.

The bowl vent has got a green arrow and you DON"T want to plug that or your car won't run. Some guys stick a filter on that, but it needs to be open.

The purple arrow is to the EGR valve and there's no reason to do anything with that... No vacuum there. The valve could even be removed and a block off plate fabricated to cover the hole if you wanted, but nothing that you need to do

Anytime you have an open vacuum, you are leaning out the gas/air mixture on the carb and can give you some grief. In fact, your idle being too high could be caused by this.

Is there something else I'm missing?

 

[thethee]

Might want to upload some pics of the rear of the carb to show the vacuum connections and maybe carb number.

66 shouldn't have a sensor in the air cleaner. Yes, a vacuum leak can very well cause rough running especially at idle.

Just realised that neither carb nor engine are '66... So this might still be good to check.

Engine appears to be emissions era while carb appears non-emissions.