according to the S5 FSM on page 8 of 77 found here; http://208.62.166.66:82/guest/shop_m..._non_turbo.pdf

it shows that the secondary and primary air bleed socket nipples pull air from a common hardline which is shown to route up to the throttle body and pull metered and filtered air from pre-throttle plate. however, there is a fundamental flaw with that; i have no pre-throttle blade nipples from which to pull air from.

on the same note, i dont know where that hardline disappears to. since its in the same clusterfuck as the ACV, 6pi, etc lines, it apparantly connects to the rodent nest under the UIM, and runs over to the Solenoid rack. the only logical assumption is that this hardline which feeds all 4 injector air bleed sockets pulls air from the solenoid rack... but it shouldnt be switched.

where can i pull metered/filtered air which will draw from before the throttle blades?

this is a 90 GTUs. ACV, 6PI, AWS and all associated vaccum lines are removed. im leaving the rodent nest under the UIM as its affixed to the fresh air pipe which feeds all 4 oil injector air bleeds, as well as the AWS solenoid... which i should be able to just disconnect the 2-wire connector which connects to that, or will that throw a CEL?

oh, yeah, im also keeping the VDI operational, i just need a pressure source which will open the diaphragm. i think im just going to keep the Smog pump and plumb it directly into the releif silencer and plumb the vaccum pressure source into that. would dumping the entire pump output thru the silencer still provide enough pressure to operate the VDI diaphragm when the VDI solenoid opens at 5000rpm?

thanks
chris

 

Uh, what happened to them?
Are you using a non-stock intake manifold?

Any fitting BEFORE the throttle body will work.


-Ted

 

i don't know if this will help at all:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/i-need-vacuum-line-gurus-here-453746/

 

heres another thread that may help:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/write-up-rats-nest-removal-thats-13btii-specific-365491/

 

Yes you do. Several of the nipples on the front and rear of the UIM are fed front in front of the throttles via passages in the TB, TB spacer and UIM. I'm not sure which are which on NA's, but someone else probably does.

Maybe, but even if it doesn't, that's easily fixed by installing a ball valve into the relief hose. Closing the ball valve a bit will cause a restriction and increase upstream pressure. Close the ball valve just enough to give you the 3psi the VDI actuator needs.

Good thinking on the use of the relief line.

 

thanks ted, but my TB has absolutely ZERO nipples on it, which is what the FSM seemed to indicate. the FSM gave me the impression that there should have been nipples on the TB itself. i found that the TOP nipple on the intake plenum, which bolts on top of the UIM, feeds into the port which is centered between the 3 throttle throats. the bottom 2 nipples on the plenum both feed POST-throttle plate, into ports molded into the TB spacer.

back to the center port in the plenum; it continues thru the TB spacer and into a port drilled into the center of the TB throats. it pulls air from a 2mm port drilled directly infront of the primary throttle blade. Huzzah! so ive got a pre-throttle source for metered/filtered air to feed the fuel injector air bleeds.

what do you think about connecting the smog pump output to the releif silencer and sourcing that output pipe for pressure to operate the VDI... do you think there would still be enough pressure to operate the VDI? either way, i think im gonna give it a try and see if it works. just wondering what you think.

thanks
chris

Edit; just read the 3 last replies. thanks jason and everyone