Ok, did an A.I.R. tube replacement on the passenger side ('89 305 TPI, un-molested)
All went well, but, when I start it up, it immediately wants to idle at ~2000 RPM and stay there.

Snooped around and found a stray vacume I musta knocked off.

Stay with me here (Emissions legal guys look under yer hoods):

On the passenger side, there are 2 small (I'm guessing 1/4") vacume lines that come up from between the firewall and the engine. One runs straight foward and plugs into the top of the Air Injector Control Valve (AICV).
The other, same size line, originates from the same area but bends towards the plenum, points in the neighborhoor of the EGR Valve. Right now it's just laying on the pass side valve cover.

For the life of me, I can't find where that sucker goes. It has to be the source of my high idle too.

Ideas..................
RB

 

If you're talking about the air lines(which I'm not sure you are, since they should be at least 1/2" in diameter), one goes to the catalytic converter, and two others connect to the exhaust manifolds. The AIR system will not cause a vacuum leak.

Check the egr valve, your brake booster line, and the the connections on the back of the plenum near the fuel pressure regulator. You could also have a leak at your throttle body, but since you didn't touch that area I'd doubt it.

 

Forgot to mention that part....while I was under there I did slip the plenum off to check my EGR. (Had problems there for a while but has always runs fine, just the usual code 32 thing).

I loosened the drivers side lower runner bolts, took the plenum and throttle body off. I'm positive I torqued them down.

So will an air/vacume leak between the throttle body and plenum cause a high idle? I'll re-check the torque on those suckers.
15 lbs as I recall.

Still aint found where that stupid vacume line goes tho.....

RB

 

Slack,

TB and plenum/runner bolt torque should be 18 ft/lb. Some bolts have a specified range of 18-20 ft/lb, so a good rule of thumb for all intake and plenum bolts on a TPI is 18 ft/lb.

As for the vacuum lines, maybe this would help:

 

anyone got a diagram like that for a tbi?

 

Thanks Vader for the schematic.

Mental note: Gotta get me one of them manuals

It was a hose in the HVAC system. The port off the rear of the plenum has a 1/2" hose on it. That 1/2" hose is ~3" long then splits into 2 hoses via a plastic splitter. It was one of the small hoses that plug there that I had flopping around there.....

Thanks
RB

 

A Chilton's manual has them all. If I could connect my computer at home to the internet, I'd scan it for you.