Cosmo Kramer

I have tracked my vacuum leak to something around the throttle body. When I touch the throttle even slightly I get a whistling noise coming from that area. Is it possible to remove it through the middle ie. where the center intake goes, or do I have to pull the fuel rails and all of the tubes as well?

Mike Frye

Ah!

Sorry about that. I think you're going to have to pull at least the passenger fuel rail and one or both of the intake runners on the PS. I had a problem with mine after I got it all back together and had to do this. I don't think there's any way around it.

Once you get it on the bench, you can test it with a setup like this though, it will eliminate all the guessing:Intake test jig setup thread

Cosmo Kramer

Thanks Mike, I am going to see if I can remove the center intake tube and root around in there for a bad hose to the ISV etc. before I go ***** deep and yank everything off. The PO put new heads on the car before I got it and I am wondering if something was knocked off or not properly tightened during the installation.

I have checked every vacuum line that I can reach and all the rubbers going to the intakes and they are all holding, the idle switch is closing (tested through the EZ-K). I think this is my last option.

Mike Frye

Good luck,

If you are able to get it out without pulling everything, let us know.

You might try this stuff, I think it's called Leak-detect or something like that. It's used for finding leaks in natural gas pipes and you can get it at Lowe's or a plumbing supply place. It's blue and comes in a squirt bottle.

It's non-corrosive and when you pressurize the system you can spray this around and it will bubble up wherever there's a leak.

Good luck and keep us posted! (I hate vacuum leaks)

Cosmo Kramer

Mike, looking at the pic you posted, am I correct in saying the center intake has 2 large vacuum lines to it, the one for the ISV and oil filler neck?

What has me scratching my head is that the leak is only audible when I crack the throttle, otherwise I can't hear a thing. Could be an air velocity thing, who knows!

Mike Frye

Ted,

That's right, that upper 'T' section has two large hoses coming off of it, the one to the rear is the large ISV hose. The one in front of that comes out from under the intake on the DS. I think it goes into the PCV system over by the DS side box, but I don't remember. The one shown on the left side of the pic toward the back goes to the base of the oil filler neck. It has a pcv check valve in it.

If you hear vacuum suction when you touch it, you might just have to tighten the hose clamps holding the upper 'T' onto the TB. You can use the MAF cap I have shown here while the TB is in the car too, so you can pressurize the whole system before taking anything off. It will pressurize the whole crank case though, so the dipstick has to be in and the oil cap as well. This is good for testing the entire thing so you don't have to listen over a running engine.

WICruiser

There are smaller vacuum lines that run to the top of the throttle body, and I am faily sure at least one of them is not under vacuum until the throttle is cracked open.

I think you can access them with the center T removed but without removing the fuel rails or the other intake legs.

Cosmo Kramer

Thanks, I am going to attempt to remove just the center "T" intake and root around in there for leaks.