I'm just stripping off the vacuum spider.... and I just have a question.

I've heard that the injector bleeds (the ports by the injectors that have vacuum lines on them) need to be hooked up BEFORE the throttle plates...
On mine- they go to the BIG hose on the spider that the OMP lines come of...

So- do I hook the bleed lines up to vacuum, or open air w/a check valve to prevent boost from leaking out?

What about the OMP nozzle lines?? Open air or vacuum?

I'm confused.



Can I just leave them open air vented?? (Maybe to a check valve to prevent boost from leaking out)



Thanks!

 

Why don't you put them in their factory locations?

Chris

 

Yes - there are 8 altogether - 4 for the fuel injectors & 4 for the oil injectors. Their supply needs to be at or above the UIM pressure, which is available between the IC & the TB.

 

Ye, there are three nipples on the back of the upper intake manifold....
The oil injector lines (teed into one) and the air bleed lines (again, teed into one) are the last lines, and I need to know which of the three nipples to hook those lines too, and if I should block off the third.

 

when you dont know, put it back the way you found it

mike

 

I got rid of the vacuum spider....
Makes it a little difficult.
I know what I'm doing, but I just dont' have any info saying which of the three nipples the oil and bleed lines hook up to. They go to different points inside the manifold/tb.

 

hey..i just got done porting my manifolds...and i have exactly the same question..but i have a spare motor thats still together...so if no one answers by tomorrow..i'll figure it out and tell you...

-Pat

 

you can't just leave it open (even with a check valve) because it will be a vacuum leak. Unless you switch to a speed/density sytem.

Either connect it to the source before the TB or plug it. It will just hurt fuel atomization in low intake velocity conditions (low end) to have it capped.

 

well on the TII UIM. there are 4 nipples on the back. one is vac / boost. and other other 3 are not. they are bypassed around the TB and get air infront.

you could probably tell what your nipples are by blowing though them. and figure out where they go. asuming some of yours go around too which they must.

 

Yep, tried blowing into them, and they all go to different points inside the TB. Hard to tell.

 

ok..of the three lines...the big top one is for oil injectors, second one is the primary injector bleed and the third one you dont need anymore plug it.

-Pat

 

Thanks for the response...
You say the BIG top one?
On S4's apparantly there is a big one, but on S5's they are all the same size... are you still talking about an S5 TB or an S4 one? They are different.
And what about the secondary injector bleeds? They added those in 89 too. Do I just tee those in with the primaries?? In the FSM they look to be the same hose, but other people have said thay have a seperate source.. I'm inclined to beleive the FSM though.

Also.. estiating by the FSM, it looks like the injector bleeds are the top one, but also could be the source for the ACV solenoids....
Oh well,I'll just start the damn thing up and see which is vacuum and which isn't

 

Smoke is the best way to trace those passages. Stick a length of hose on each nipple and blow smoke through them. I'm betting that all three will come out in front of the throttles. One for the oil nozzles (the big one) and one each for the primary and secondary injector bleeds.
If you look at the front of the TB there's a hole in between secondary throttle bores (~6mm diamater). That's where the air for the air bleeds and oil nozzles goes in. You could blow smoke in there too, to see which nipples it comes out.

 

I know there should be a hole there- I've seen it on other TB's, funny thing there is no hole.... There is a circle inscribed between the throttle plate bores, but there is no hole!! I know there has to be a bypass for the idle somewhere in there though- it doesn't make sense. I've got the whole thing apart now.

Anyways, about the nipples...
I can blow into them, and hear it coming out of different parts of the throttle body.
Oh well. I'll figure it out tomorrow...
ALso, why do some people keep referring to the nipples as having different sizes?? Mine have three- all the same size.

 

On mine and others I've seen the nipple for the oil nozzle spider is much bigger than the others. Maybe 6mm instead of 4mm.

 

No smoke????? It's very possible that someone flipped that black spacer 180 degrees.

 

Slightly off topic, but approx how much air should be going through the secondary and primary inj vac lines.

What I mean to say is that my sec inj vac is much harder to blow through then the primaries.. The primary vac line seems to have little resistance and accepts alot of air. I am leaning towards a problem with the installation of the primaries??

The idle is high when the primary vac line is hooked up correctly. Some mechanic put it to the seconday throttle valve actuator line (after throttle), i guess to force it to idle lower.

 

on hte back of the S5 UIM, there are three nipples...the middle large one goes to the 4 way split to the oil injectors. that leaves either the upper one, or the lower one for boost/vac.

i have it so there is a vac line going inbetween the secondary injectors, then the nipple on the OUTSIDE of the injector towards the back of the car goes to the nipple before the TB

 

Bam Bam,
I'm going back to your original question:
This is referring to a normally aspirated S5 intake.
The injector bleeds should be supplied with filtered, metered air from in front of the throttle plates. The big pipe on the spider rack is supplied from the air intake tube. It also feeds to the BAC and AWS valves. If you're keeping those solenoids, then use the factory source on the intake tube for everything. Well, I guess, even if you're not keeping the BAC, the source is still there.

The three nipples on the UIM at the throttle body spacer: middle one is vacuum for relief & switching solenoids. Top & bottom nipples are tied to each side of the purge control valve diaphram. A differential in vacuum between the two operates the purge valve. The FSM diagram shows them sourcing from between and behind the primary & secondary throttle plates. Therefore, they would be unsuitable as air bleeds.

 

Beatiful.
There seems to be a lot of confusion about these!

Well, thanks Curtis, I'll just block them all off (actually, I need the one vacuum source for the cruise control..) And use one of the big air tubes off the elbow.

Thanks!
The FSM is pretty hard to decipher with those locations...
It clearly shows the air bleeds going to one of the nipples though.


Dan

 

Read the thread

https://www.rx7club.com/forum/showth...hreadid=195776