I have just about wrapped up my vac line issues but I ran into a little problem.

My truck (87 p/u 22r MT FED) has a vacuum part that doesn't appear to be listed in the 85 FSM.



It is mounted on the passenger wheel well, right next to the VSV and the vacuum switch. One of the lines goes to a tee and I can't figure out what is supposed to plug into that tee.


If anyone can identify what that mystery part is and more importantly what is supposed to plug into it I would appreciate it.

Here is the section out of the 85 FSM so you don't need to dig it out

Thanks for the help



-frozen

well it's the same as my truck but I can't tell in your pic what you are pointing at that it's supposed to connect to.

Maybe this picture will be a bit clearer



I am trying to figure out what the piece with the black cylinder on one end is. It has two vac lines coming out of it. One of them (the one with the two arrows pointing to it) goes to a tee and I don't know what plugs into the tee.

Any ideas?

Thanks

-Pete

That's the A/C idle up systemà dunno if your truck still has it, but originally there was another diaphragm on the throttle lever that idled the motor up when the A/C kicks on. That's where the hose goes.

Yep.

Great, thanks for the info. There are 2 vac lines that go to the A/C idle up system. One goes to a dashpot located near the throttle linkages. That line is connected.

The other line is the one that I can use some help with. Does anyone know where that line goes to?

Thanks again

-Pete

It's been awhile, but seems to me it hooks up to the HAC valve if you have one. See the diagram, left side. Might also go to the charcoal cans. My '86 has the HAC and AC.

The dashpot only came on trucks with an auto transà the A/C valve (with the black cylinder thing on it) should have 2 linesà one to manifold vacuum, and one to the idle up diaphragm.