Alright, I've a s4 with everything removed and blocked off. No vacuum spider and all of the intake holes were jbwelded over so I know I don't have any leaks from any of the nipples.

I thought I found the vacuum leak between my dynamic chamber and the runners( where the upper intake mates on the driver's side). It had the OE gasket and I went ahead and replaced it even though it looked fine. Got it back together and still have a vacuum leak. It is pretty sizeable and I can hear it sucking pretty hard from 1000-3000rpm. It won't idle at all.

I sprayed some starting fluid around and if I spray down below the runners towards where the fuel rail area( primary, the ones bolted to the housings). Do you think that a leak there would be big enough to be audible and cause it not to idle?

My other thought was maybe the gasket between the block and the lower intake manifold was bad.

Any suggestions or ideas before I tear in to this again? I guess I have until Monday to decide what parts to order..

 

fuel injector orings?

 

Well, I think it might be because I made my own fuel rail insulator and it might not be allowing the fuel injectors to sit right. But I would think that would fuel to leak as well. It isn't though.

I replaced all the fuel injector o-rings when I put the car back together. Some parts got lost in the mail so I made do without them.

 

Don't always believe jbweld sealed the intake. I did that on mine and where the ACV was the motor sucked in part of the jbweld at the top bolt hole. Didn't effect my idle or running, but it sounded like a vacuum cleaner when idleing

 

hm.... I've got regular block off plates on most of it. I've just vacuum caps filled with jb weld on the nipples. Oh and a quarter jb welded over where the BAC valve was.
I'm trying to get a hold of a stock s4 manifold so I can restore it back to factory. The PO had everything removed other than the BAC. (Thermowax, first set of butterflies, etc; alre ady removed.)

 

Alright, update, that took about 10 seconds to take the intake apart and wiggle one of my primary injectors. The bottom, fat o-ring is missing on one of them. Which seems like I would've noticed by now? I even had it idling fine at one point.. That's sort of weird isn't it?

Now I have to figure out where to get this o-ring. rofl.

 

did you use a sealant on the block off plates?

 

Yes, the leak is from the fuel injector o-ring though. There is nothing else under the intake to leak and it was missing so....

 

injector o-rings are nearly universal.

they were under 3 bucks for 1 injectors worth of uppers, lowers and insulators at napa.

 

you dont say

 

Well, I've ordered the three intake gaskets, orings, and the fuel rail insulator; so hopefully I'll have my car back together Friday. Does anyone know if the intake to block gasket is supposed to be three separate sheets?