chaadster

Hi Y'all,

I'm hoping someone can help me determine where a specific vacuum line leads.

I was following up on a slightly high idle condition I've had for awhile, and figuring it was probably a vacuum leak, started checking the lines. I pulled on one that originates on the passenger side from some unidentified device, and dives under the passenger side fuel rail, continuing down underneath the intake manifold. It pulled free in my hand, and the end looks melted and deformed.

I pinched this pic from Tony's site (I hope you don't mind, man!) to explain. The line in question is labled 18. BTW, does anyone know what it connects to, i.e. 11?

Thanks for the help everyone.

whitefox

I just went out and checked my 87, it does indeed attach to 11, there is a U shaped hose it attaches to.

chaadster

Thanks, Ross, my hose is still attached to #11, but I was wondering what the line attaches to underneath the intake manifold. I'm curious if that could be the cause of my high idle, and also how I might fix it.

GregBBRD

That hose attaches to the top of the throttle body assembly under the intake system. You can see it by removing the air cleaner assembly and air flow meter. Right at the top of the throttle body, where the rubber boot attaches, are two brass fittings that come out of the throttle body assembly. They are 90 degree fittings. One faces towards the rear of the car and has a hose that goes to the "7 way" vacuum connector that hooks all of the pressure regulators, dampners, etc. The other faces forward. That is where the hose connects. It should have a straight rubber coupler on that end.

greg brown

docmirror

Greg's got it. And yes, that will have an affect on the idle if it is leaking or melted or not connected. It is a primary vacuum distribution point, and although it doesn't flow much, it goes to many different places, alll of which can cause idle hunting or high idle problems.

Doc

whitefox

I have everything apart, here is a picture for you.

chaadster

Perfect! Thanks guys! For the id, for the pics, for everything! Off I go to fix it...I was worried I'd need to pull the intake to get to it, but it looks like not. Lucky.

Great pic, whitefox!

IcemanG17

So its the vacuum source that varies with engine load....I would guess your car shifts hard too, sense the tranny will sense no vacuum and shift full hard all the time?

chaadster

Hey Brian, you're right...it does shift hard. I didn't even think about that being a related issue.

After laying spread-eagle across the engine with my head wedged in behind the motor (I know, not a pretty picture!) and contorting oddly, I managed to extract the hose from under the intake (I knew the hemostats I've been holding onto would come in handy for something!) and reinstall new silicone vacuum hose. My hope there was that the silicone would resist the melting that killed the original line.

I can't wait for my radiator to arrive tomorrow so I can see how the thing will run (and shift) with proper vacuum.