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]

Here is a picture of the offending hose...

(IMG:http://www.914world.com/bbs2/uploads_offsite/bio2.elmira.edu-25740-1628801394.1.jpg)

[emerygt350]

I think I have returned the PCV and Aux Air to 'stock' now. Looks like either confusion or an attempt to make the pcv passive led to the PO running the PCV to the air box but that doesn't really explain why they hooked the fresh air port of the aux air to the plenum. Anyway, moved the PCV to the plenum port pictured above (which I believe is where it should be, or actually the one north of it, but I wasn't going to swap them), and put the aux on the air box where the PCV used to be plugged in. Started right up and actually idled cold where it was supposed to be (1300ish) without me even getting into the car. Now to drive it and see if it comes down as it should etc.

[emerygt350]

THe aux air is working perfectly, however, my pcv is not. That might explain the bad passive rerouting.

Cleaned the PCV but no good, just way too much air gets through. Plug it with my thumb and it idles perfectly. Going to try that corolla PCV cheat.

[emerygt350]

popped the corolla pcv on there. Now I have the hung idle issue (pull the engine down to 1k and it idles normally at 900, otherwise sits at 1500). I know it is still the PCV since plugging the pcv with my thumb causes it to idle prefectly.

Anyone know a cure for this? I thought the new PCV would do it. Apparently not and I would rather not go back to a passive system unless that is the only cure.

[emerygt350]

Did a deep clean on my original pcv and put it back in. Not perfect but a little better than before. The toyota thing would work in a pinch but it doesn't make it better.

[Sea Rooster]

Following your progress since I have a similar issue. I have a low idle until it's warm. I've used 3 separate working AAR vales with no luck.

[emerygt350]

Once I hooked that aux air up correctly it really took over at cold start. I just replaced all of the injector seals, intake gaskets and runner boots too so I am not chasing leaks.

Does your aux air plug into your cold start valve? Just curious because mine does and it looks different from what I see in Chilton's and clymers.

[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.

[emerygt350]

Just to add a finish to this story. 99% sure it is just delayed hit on the vacuum retard. Drove a couple hundred miles since the last changes and still hit or miss on the hang. Runs so good I have decided to ignore it...