Vacuum lines

[kabniel]

Does anyone have pictures or detailed instructions of their AFI TBI install?
I am having a hard time trying to figure out which vacuum lines need connected & which ones dont. There are multiple ports on the throttle body that have nothing connected to them & I just want to make sure I get everything connected properly. The directions that AFI provides basically tell me nothing about hooking things up properly. I am not even sure the throttle body is installed properly, the fuel line adapters that came in the kit hit the mounting plate & cannot be installed.

[ihojeff]

These pictures should answer your questions as to vacuum hose routing.

EDIT - I can't seem to find the picture I was looking for. As soon as i find it I will post it up.

I'm not sure what problem you are having with mounting the throttle body. If you can post a picture of the problem you are having.

[kabniel]

I was not sure if the mounting was correct or not. The throttle body is basically positioned above the smaller holes on the spread bore intake manifold with a larger portion of the adapter plate open to the rear. The 3/8" fuel inlet and the 5/6" return adapters provided will not clear the back of the TBI spacer/adapter plate to get the threads started.

[kabniel]

I was able to get the lines connected by bending them. This is what it looks like now. The adapter plate is sitting on a spread bore intake manifold so the throttle body is actually sitting above the smaller holes on the intake. Is this correct? Has anyone else had to bend their lines to get them connected?

[Bill USN-1]

I can't speak directly to AFI installations but when I do conversions on a 2 barrel I put them in the middle.
When I do it on a 4 barrel I put them over the rear on a spreadbore and it's owners preference on a squarebore.

For throttle hook up I found the fwd position better.

The way you have it will work.


This may not be new to you tho.
Not sure how much of the FAQ's you've been through over on the BB but I know I've seen you there a couple times.


What is that hose your holding? If that is connected to the intake runner, I prefer to remove it and put the plug back in.
Run you brakes/pcv from full manifold vacuum not 1 runner.

If it's the heater hose going to the manifold then alls good.

[kabniel]

I thought that on a Spread Bore intake the TB should probably sit over the larger openings. I was just wondering if maybe the adapter plate was drilled incorrectly (backwards) so that the TB has to be mounted over the smaller holes.
Yes that line runs from the intake to the brake booster. So I should have a T in the line to run from PCV to TB & also booster? If so that works for me, just means I can delete another connection, sort of.

NEW: Can anyone tell me if the throttle body is installed correctly in the picture above or not? Is the TB supposed to site above the larger or smaller openings on a Spread Bore? There should be an absolute correct way of installing it on a Spread Bore intake not just a "it should/might work fine like that" answer.

[Eagle-Mark]

Every spread bore adapter I have seen puts the TBI unit over the rear large holes. Here's a link that shows the same and your diagram needed for vacuum lines.

Parts Needed For The Gm Conversion - Binder Bulletin Forums