73 2.0 aux air routing Options

[emerygt350]

Just trying to make sure everything is right and I noticed my routing seems different than Chilton's diagrams (terrible as they are).

My aar goes from the passenger pointing top bit to a port on the plenum near where the t is for the decel valve hoses.

The lower, driver pointing aar port goes to the cold start valve (that seems right).

Needless to say I don't think having it go to two ports on the plenum is right. Suggestions? What should be going to that port on the plenum if I pull the hose from the aar? And all of my ports on the air cleaner are occupied so where should that hose from the aar connect?

[emerygt350]

Well... decided that it might be a hanging vacuum retard. Sure enough, if you disconnect the retard (and plug the port) and plug the PCV the idle shoots to 1500.

First I switched the PCV to the port north of it on the plenum (where it seems to be on all diagrams). That port is smaller and that made a small difference. The decel valve is now on the old port which is bigger (PO had even put a hose clamp on it to make it fit the PCV plenum port).

Still no big difference though. Still hanging throttle.

Pulled the distributor and gave it a good cleaning and lubed up the advance retard mechanism. Vacuum diaphragms are all good, replaced the condenser just cause I was there.

Still not excellent but noticeably better. It was really gunky and difficult to actuate before I cleaned it.

Plugged the PCV with a hose I drilled a small hole in to replicate a closed PCV and noticed that the retard on the distributor was now so great the idle had dropped to <500 and no twisting the idle screw would bring it up. Started advancing the timing in this condition until I got a nice 900 rpm idle with the idle screw in a sane place (maybe one turn out). Hooked the PCV back up and it appears to drop to that 900 now at idle but with a smaller hang at 1400, which given 5-10 seconds seems to drop down to where it should be at 900.

Took it for a little spin, sometimes would drop right to 900 with just a hair of hang (less than 2 sec) other times a little longer. I no longer believe the issue is the PCV. Fairly certain the only thing left is the TPS or still a sluggish vacuum retard. Tomorrow I might get a vacuum thingy and give it 'artificial' retard all the time and see what happens when I rev the engine. If it doesn't hang then I know it is just slow actuation of the retard that is causing the problem. IF that doesn't work than I guess it is on to adjusting the TPS (I rebuilt that already and set it out of the car).

and then I sandblasted some surface rust in the trunk because I needed to feel l like I accomplished something concrete today.