Does it matter which way the vacuum lines get hooked up to the solenoids?

Follow the diagram, which you probably already have. Note that the vacuum connections use a stepped push on connector that keeps source and destination ports pointed to the correct place.


The TAB/TAD solenoids are tapped into a vacuum source that uses a check valve and vacuum reservoir. My guess is that this keeps a constant vacuum at low vacuum conditions like Wide Open Throttle. That keeps the valves and vent system working when you hit WOT. It would suck to have a car that closed the vent system every time you floored the gas pedal. The TAB solenoid is the one that causes the smog pump to dump its output overboard at WOT. If it didn't have good vacuum at WOT, it would not dump. That could cost you a few HP, so make sure that you have it plumbed into the check valve and vacuum reservoir for its vacuum source.

Diagram courtesy of Tmoss & Stang&2birds


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

if you're speed density, be sure to hook it straight to manifold vacuum, and also, the fuel pressure straight to manifold, otherwise, as long as sources get vacuum, I do believe you should be fine.

maf gets no vacuum at the map, other than that, everything is pretty much the same. I've used skinny rubber line to connect broken parts of that brittle stuff before and it worked ok. Just be sure to take a vaccum reading after, expect a steady 17-20 pounds if you have a stock cam.

If I removed my smog pump crap do I still need the TAB/TAD solenoids?? Removed them yesterday and now I only have the EGR vacuum regulator. Is this bad?