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So two of my vac lines on the ported vacuum switch on top of my valve cover are not attached to anything. My motor is misfiring and I want to address the obvious issues first. I've been looking all over for a diagram for these vac lines and where to hook them up to but I cannot find anything that I remotely understand. Please help!

1989 Jeep wrangler yj. 4.2L
 

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Someone will get you pics.
In my factory service manual diagram for a 93 4.0, the port closest to the interior firewall is the line coming from the top of the manifold. The port closest to the front of the jeep goes to the top of the air cleaner. Hope this helps. This could be bad info because efi/tbi by 93.
 

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Look under your battery box for a black plastic ball, about the size of a softball. There should be three nipples on it. There should be one large and two small nipples. See which hose fits on which nipple.

I don't have a diagram available right now but let us know what you find.

Good Luck, L.M.
 

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From the photo it looks like you are still running with the factory Carter BBD.

If you are certain that the engine is 100% stock and still running with the computer then you should visit this website and get to know it well:

Adventures Under the Hood (main page)
Vacuum Hose Schematic
Vacuum Details (Three links on this page - computer, EGR, TAC)


In the site linked above you'll find just about everything you need to know to keep the factory 4.2L computer controlled engine setup in running condition. It will also have vacuum line diagrams for the 4.2L engine. The site references the CJ, however the 4.2L YJ is essentially the same setup.

If you are not running stock, verify that the Nutter Bypass has been done properly. The vacuum lines post bypass are simpler than stock and will be like this.

:drinks:
 
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