I'm having some trouble getting my idle where I want it on my new rebuild. I'd like to get my facts straight;

There are three, and only three ways for air to get past a closed throttle:

* Through AWS pipe / solenoid
* Through the ISC
* Through the air bleed screw

..correct?

Also, with the AWS and ISC blocked off, I should be able to make the engine sufficate by closing the air bleed screw, right?

If I'm right about the above, I have a vacuum leak. Please tell me something I don't know.

Thanks.

 

your not going to be able to set idle until the engine is completly broken in............it needs to build compression

After rebuilding my TII it took 4k or so for me to finally be able to set a consistant idle.

 

I found the forth way for air to get past a closed throttle today. I knew about it previously, but didn't think about it when I wrote the above.

There's a hose from a nipple pointing downwards off the drivers side of the Y-pipe, connected to a nipple on the LIM, close to the front secondary injector.

Can anyone come up with a justification for the existence of this hose?

 

Can't seem to find any particular reason for its existence in the manual, though they do show it in both the routing diagram and the vacuum line schematics (listed as the "A" connections). I recall that connection routed right into front secondary runner in the LIM? Hmmm.... maybe an attempt at pressure equalization? Weird...

I was of no use and should delete this post. But I ***** on!!!

 

That nipple feeds from the y-pipe coming out of the turbo, (stock twins). It then feeds through the LIM and into the primary injector boss, right around the pindles in the injector. They are real small holes in the boss. I did have a vaccum cap on it but it cracked and fuel was leaking ever so slightly out of the nipple and pooling in the little pocket between the rotor housing and the LIM.

I tapped and plugged mine. If it is not capped or plugged I guess it would cause a minor vaccum leak. By the way use gaskets on all block off plates. I had a hunting idle due to a vaccum leak around the EGR block off plate. I only found it by spraying brake cleaner all around eveything.

 

Oh yea. I still could not set a steady idle after fixing the leaks. What I did is backed the upper throttle plate back a little with the threaded screw/nut on the throttle body. it is the one that adjusts the stop of the upper butterflies on the top. It's not the one that sets the stop of the throttle. Purrs like a kitten @ 800 RPM with 300 miles on a ported reman @ -41cmHG of vac so far, and climbing. Started with -37 at the first startup.