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Old Apr 12, 2010 | 11:28 AM
  #1  
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Vacuum Lines

Hello everyone.
I hate to ask questions that I am sure have been asked 1 million times already, so if someone can politely point me to the right forum, I would appreciate it. I searched.

Vehicle is an 83 with the 4.9 4wd, 4 speed manual.

I need a vacuum digram or maybe just some really nice pictures.

I replaced the exhaust manifold gasket and removed most of the vacuum lines and replaced them too. I took notes and put them all back in the same place.
But I did take off the smog pump. It had no belt around it, was not working, but did have the lines ran to it. I plugged them all up. I also put on a new valve cover and breather valves on the valve cover. (Just trying to be detailed).

Symptoms: Starts and runs , idles very rough, very rough. (Was not the case before I messed with it, it used to idle fine). When I apply some throttle, it works fine, but then stall out after I let off the throttle.
I hear some hissing from the engine, like a vacuum line open, but cant find anything? COuld the breathers on the valve cover be this loud? Could it be too much air with the breathers? I have tried things, but I cannt get it to work. The truck did sit for about 6 weeks, so perhaps I need to have the carb cleaned redone now? I just cant figure this out. I know nothing about carbed vehicles. Any suggestions?

Also pics of the engine compartment with the vacuum lines will help greatly, I do mess things up occasionally!

Thanks in advance!
 
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Old Apr 12, 2010 | 12:30 PM
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Unless it's been removed (never know why people do that), there should be a vacuum diagram sticker near the front of the engine bay. Should be just to the left of the hood latch.
They're pretty explanitory as far as where all the lines go, so follow it closely. The easiest way to learn to understand one is start with something on the diagram that you recognize, such as the EGR valve, since it only has one line, or the ported vacuum switch at the front of the engine, since there's four distinct lines top to bottom, and the diagram has them listed top to bottom. Follow your lines in the engine bay as you follow the line on the diagram, keep track of where they T, where they connect, and see how they correspond with the diagram. Takes a little doing, but pretty easy after a while. The 300 is a pretty simple vacuum line setup compared to the V8s.

That being said, it does sound like something with your vacuum is messed up. I removed my smog pump and EGR valve and capped off the vacuum lines and had very little drivability issues from it besides some tuning problems with the carb (from running lean due to no emissions equipment), but nothing like you're describing.

If you can actually hear hissing in the engine bay, it is probably a pretty big leak. Check for cracked base gaskets underneath the carb, and check that all the caps you put on for the smog pump are tight and completely sealing. Then double and triple check everything else.

Good luck!
 
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Old Apr 21, 2010 | 09:58 PM
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vacuum lines

i need the same information the person who had the truck from me has the lines all messed up and there is no diagram for me to go off of please if anyone out there knows where we can find a vacuum line diagram to know where they all go please let us know something
 
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