CEL on, Vac lines connected improperly need to sort- P401,P402 MYSTERY (1 Viewer)

[Adrians80]

First off, thank you, MUD community. I've searched through multiple threads for solutions to various problems, and because of the wealth of knowledge here on MUD, I have been able to find the answers I need to fix the issues I have encountered. I have never needed to post a question myself because I have always been able to find what I need. That being said, I now have a question and need some advice that I have not been able to research and find.

background info:
recent purchase
1996
177k miles
PO had "a guy" attempt repairs
PO Replaced VSV and moved it out to a more accessible location
I replaced EGR valve
I Replaced EGR Modulator
I noticed lines incorrectly ran to VSV
I am not a mechanic but a DIYer that often gets in over his head
I do not have the FSM
I was getting p0401 and p0402 but after replacing EGR valve and modulator i am only getting p0402 still with CEL
truck drives like a dream, idles rough while stopped though.


As title states, some vac lines are connected improperly. Specifically,

• The line from the "T" (see diagram) to the VSV has been plugged
• One end of the VSV correctly goes to the EGR, the other goes to a mystery(to me) port.

I know I need to connect the plugged end from the "T" to the VSV.
I do not know where the line that is currently improperly connected to the VSV goes and need help identifying it and routing it to the correct location or what to do with it.

Pics:

Please let me know if you know where that line is supposed to go.
Thanks - Adrian

 

[jonheld]

I do not have the FSM

That's your issue right there. Download it from the resources section. Free-fer-nothin.
Pages EC-2 and EC-3.

 

[Adrians80]

thank you!!! I downloaded it and wow this will be very helpful.

However, I still cant identify the port from my picture above.

The best diagram (below) shows the VCV but does not show the bracket its mounted to. In my pic above my VCV is attached with a bracket that has a metal hardline port on it. Similar to the one for the VSV.

 

[Adrians80]

SOLVED! Turns out this hard line is the port that should be capped. see photo from the diagram under the hood. Not sure why this isn't shown in the EC-2 diagram but that's what it is. I had to remove the bracket to access the area below the intake manifold and press my head down in the engine bay as far as I could to see where the line terminated.

Plugging this line swapping the other to my VSV has solved my rough idle and *so far* the CEL.