[deltadukman]

So I get the intake/exhaust manifold gaskets in. Hook everything up, and seems to work fine, then i get to the bottom of a hill, get on the brakes, and chokes the motor down until it dies. It is a 1980 CJ5 258 six, with power brakes and steering. I thought I got everything hooked up correctly. Does anyone have a diagram for the vaccume lines?

Several things:


I did notice my "vaccume advance" that comes out of the bottom of the distributor was unhooked when I bought it.

One my carb, if your looking from the front, there is a vaccume "port" on the right that was plugged.

There is a 2 pronged "hookup" on the lower block, on the drivers side, towards the back of the motor. It seems to be broken.



Anyone have any advice?

Also, I live in Mississippi, where emmissions doesnt meach a thing. If I can just get it to keep from choking out while braking, I should be good. It also seems to have lost some torque while accellerating.

[idl]

great site with diagrams and additional info: Vacuum Hoses

Just a guess but it sounds like a vacuum leak if the power brakes are killing the engine.

[deltadukman]

ok...my motor doesnt have all that stuff. I am sure the majority of my emmisions stuff was taken off. Also, on the front of my valve cover, there is a little valve(I am assuming a PCV valve) that is "T'd"...if you are staring at the motor, it has a big hose connected on the left, and little one on the right. It was not doing this before i replaced the intake/exhaust manifold gaskets. I did this because I ran it hot and it wouldnt idle well. It seems to idle and rund decent...but if you put the brakes on, under load, it wants to die.

[idl]

You may not have most of vacuum lines in the diagram I provided but it's a good resource for the way it was from the factory.

Where do the two T'd lines from the PCV valve go? I assume one is to the base of the carb? The PCV line is T'd for the charcoal canister but that connection is usually near the carb. Did you hook the distributor advance back up? BTW, what carb is it?

I think it may benefit you to post some photos and perhaps provide a more complete description of the vacuum lines you have currently.

[deltadukman]

Im going to take some pictures tonight and post them tomorrow. I'll check it tonight and get back in the morning. Thanks for all the help, and hopefully I can get it all put back together. I tried to hook the vaccume advance up, but thats when the problem started. Where do I need to hook it up at?

[deltadukman]

Ok...here goes. The only vaccume lines I have questions on are two sets of two coming out of the back of the air breather. I have two hooked up to two little "rods" that are next to a chrome little disc that sticks up between two manifold bends on the back side of the carb. The other two are hooked up to two little rods/tubs in front of the carb. I went to a mehanci friend this morning and se said most all all of that was unneccessary. He said my main vaccume leak is coming from the throttle control rod in the carb...sure enough he sprayed ether in it and it smoothed out. He says I need a new carb. He said that when I get the carb, the only vaccume lines we'll have hooked up are the vaccume advance from the distributor, the one that runs the brake booster, and just one or two more. Does this sound right? If so, what are yall's reccomendations for a new carb. I'm trying to be somewhat cheap.

[Mike Romain]

Here is a description of the needed vacuum lines: http://www.jeepforum.com/forum/f8/vacuum-hose-hook-ups-735289/#post6872964

All the carbs leak at the throttle shaft, that spray BS is one of the biggest sucker plays going.... The air fuel mix can easily be adjusted to compensate for this. There are idle mix screws down front of the carb for the low speed mix and there is a vacuum piston inside the stock carb that adjusts how rich the highspeed jets run. They are a variable jet with a metering rod in them. The newer BBD carbs even have air bypass pins that are computer controlled so that throttle shaft can be 'really' worn and the computer just compensates.

If you are sitting at idle and pump the brakes and the engine dies, your brake diaphragm is likely dead.

Have you adjusted the idle speed air/fuel mix screws?

[deltadukman]

Thanks Mike. That shaft is loose though. It doesnt die at idle, just when "under load"....I guess I should say that the harder I brake and come to a stop, the more choked down it becomes. He said he "richened" it up a little, and it doesnt completely die out, but you can tell its choking the engine down.

Do you think that the carb just needs to be adjusted some more?

[Mike Romain]

Engine stumbling Under braking load can easily be a bad or carboned up EGR valve. That is below the carb. I would be sure it is disconnected and it's line blocked, then I would try it to see if that helped.

The intake and exhaust manifold bolts usually need a second retorque after they have been heated up, so I would do that also. Same for the carb, they love to come loose at their base.

[deltadukman]

Mike you are the man. I have not retightened the bolts yet, but this started happening right after installing the gaskets, when driving out of the shop! I will look at retightening them though.

This egr valve...where is it located under the carb, how easy is it to check? Never heard of it before.

[Mike Romain]

if it is loose along the manifold it will run lean and the brake hit will make it even leaner.

Here is a good site to browse around: EGR Valve

[deltadukman]

Originally Posted by Mike Romain

if it is loose along the manifold it will run lean and the brake hit will make it even leaner.

Here is a good site to browse around: EGR Valve

I have sprayed ether around it and it isnt "sucking" it in. Can I just remove the EGR and plug the hose with a golf tee or something?

[Mike Romain]

Originally Posted by deltadukman

I have sprayed ether around it and it isnt "sucking" it in. Can I just remove the EGR and plug the hose with a golf tee or something?

Yes, that is the test. When the EGR gets carboned up, it can close too slow. It also have to be plumbed right so it only opens when you are on the throttle and warmed up.

[deltadukman]

So you are saying I can just take it off? Not sure if I completely understood your last post.

[Mike Romain]

Originally Posted by deltadukman

So you are saying I can just take it off? Not sure if I completely understood your last post.

The EGR is a valve that lets exhaust gasses into the intake to cool down the combustion chamber when you are on the throttle only. At idle this valve closes. If they get a buildup of carbon in them, they can close too slowly which can cause your trouble.

I have even seen them with rotted legs so they didn't close all the way or too slowly.

The vacuum signal for this valve comes from a ported nipple that only sucks when the throttle is opened. It feeds through a coolant temperature override CTO valve and a thermostat in the air filter so the engine has to be 'really' warmed up before it turns on or it will bog bad.

You 'can' remove it and cover the hole with a plate, but the engine's camshaft is designed to have the EGR flow at speed so it doesn't hurt top end power.