Engine Vac line help on a 1985 5.0 carbed stock engine - smog lines removed

[philcore3]

Not sure if there is any kind of general guidelines out there, but I am struggling with vac lines on my carbureted 5.0 with the smog junk removed. Vehicle currently runs but has super high idle (2000- 3000rpms), and I'm tackling the vaccum lines right now to see if thats the problem. When I removed all the smog junk, I'll be honest I just kind of threw my hands up with the vac lines and tried to attach them so there at least were no open lines. I don't really know if they are running to the correct locations. From playing around, i can't find any leaks, but my suspicion is that i have one or multiple lines running to incorrect spots. Where do i start?! I have a ford vaccum line manual but with the smog removed I feel like that causes more confusion than help.

 

[Mcmahst]

Is it a carb or one of those CFI units? I can find CFI vacuum diagrams, but not one for a carb. In any case, first, I would check the vacuum at idle. Post the results here. If you have good vacuum, then your issue is a likely misrouted vacuum line, not a vacuum leak. When you say you removed the emissions items, specifically what did you remove? Post pics of the stuff you took off. Good luck.

 

[philcore3]

regular carb, aftermarket edelbrock. I'll get some pics up soon and try and get a reading on engine vacuum.

 

[AeroCoupe]

Pretty decent account for doing what you want to do here:

https://www.corral.net/threads/elimination-of-egr-on-a-carbed-85.26658/

 

[limp]

I removed the nightmare of vacuum lines, sensors, brackets, " smog control" devices on my 83 car...
I would recommend you go to your vacuum source and plug it completely first to see if this fixes your problem.. Then you could go back and reconnect each vacuum line one at a time to see if you can find your vacuum leak....
remember your " vacuum tree" on the firewall goes to multi sources.....

 

[philcore3]

Its been a bit but I finally got out and got a vacuum reading. It read out at 20 inches and held steady. From what I'm reading that looks to be where it should be. As for the other lines, i plugged up all the ports to trace the source of my leak/problem. I read to disconnect everything but the vacuum advance canister. I did that and still had 3000 rpm. My final attempt was to disconnect the vacuum canister as well. That seemed to take care of the super high idle, but I'm not sure what that tells me as far as whats wrong.

 

[Mcmahst]

Hmmm. I’m no 85 expert, but I’m not sure what that canister supports beyond the AC system and maybe, the TAB/TAD valves. I’m sure it’s not part of the EGR system. Maybe as a test, hook it back up, and one by one, disconnect the TAB, then the TAD valves to see if one of them recreate the fast idle issue? Don’t leave any of them just disconnected as a vacuum leak. Good luck.

 

[General karthief]

Can you drop the idle by retarding (timing impaired?) the timing?
Idle screws backed off all the way? High idle set like choke is on?
Throttle linkage holding the butterflies open a touch?
Is there a vacuum canister on the distributor for vac advance?
Is it port or manifold vacuum? Meaning is the vac can hooked to the correct nipple on the carb?