Author Topic: '87 350 w/TBI Vacuum line questions  (Read 24801 times)

Offline RMC_SS_LDO

  • Newbie
  • Posts: 45
'87 350 w/TBI Vacuum line questions
« on: February 26, 2010, 05:10:53 PM »
Start again by saying "thanks for everyone's patience and great answers so far!"

I have been trying to learn whats-what within the engine bay on my truck.  All I am armed with right now is a Haynes manual and it seems to leave a lot to be desired.

My latest wild-goose chase is fixing all of the messed up vent and vacuum lines.  I managed to figure out that lines were missing or plugged in various spots, but the label under the hood doesn't address some of the lines.  Add to that the fact that I know little about what are all vacuum connections and what they are supposed to do, I'm really lost here.

I took a shot at connecting things and snapped some pics and tried (poorly) to label the connections.  Bear in mind, I don't have a clue what all of the components are so this may be painful...



(1) I have the MAP sensor (I think) connected to the center connection on the rear of the throttle body base (this was already connected this way)
(2) Connection 2 is running to the front of the EGR solenoid
(3) Connection 3 is going to the PCV on the right-side valve cover
(4) Connection 4 is connected to the EVAP cannister
(5) Hard line going to the brake booster



(1) another image of the MAP connection to the rear of the throttle body base
(6) Connection 6 is on the rear of the intake manifold. I think this is a vacuum line and I have it running up to a tee, connected to the vacuum cannister, cruise control (non-op right now) and the HVAC vacuum line.
(7) is a line running from the "nipple" to the left (near center) on the rear of the EGR solenoid (the nipple outboard or to the right of center on the rear of the solenoid I believe is a vent) to the actual EGR valve



Another similar image to above to give better perspective



Another pic from the driver side.  Shows where connection (6) from the intake manifold up to the tee.
This pic also shows a seperate source of confusion- the hose going from the rear of the throttle body.  It is actually coming out of the ring that sits on top of the TB and is connected currently to a vent on the left side valve cover.  No clue if this is correct.



Another pic of the vent from the TB to the valve cover???  I know this is not a vacuum, rather a vent of some kind but I have no idea what it does or if it is connected correctly.


These may be really novice questions, but I have no adult supervision here and I'm trying to get this old girl fixed up as I can and back into shape!
Tomorrow, I dive into shocks, brakes, new t-stat, radiator flush-and-fill, knock sensor, tranny filter and fluid change.


Thanks,

Allen


Offline beastie_3

  • Senior Member
  • ****
  • Posts: 3170
  • Josh
    • My truck pics
Re: '87 350 w/TBI Vacuum line questions
« Reply #1 on: February 26, 2010, 06:28:10 PM »
From what I remember, it all looks good to me. Although, I havent seen one on a regular basis for a few years.

Offline Blake_H

  • Newbie
  • Posts: 25
Re: '87 350 w/TBI Vacuum line questions
« Reply #2 on: February 26, 2010, 08:41:37 PM »
I had similar issues with my '87.  I got all the manuals, and none of them had the '87 vacuum diagrams.  I found this one, attached, and maybe it will help you like it helped me, because, like you, vacuum is not my strong suit.





Offline RMC_SS_LDO

  • Newbie
  • Posts: 45
Re: '87 350 w/TBI Vacuum line questions
« Reply #3 on: February 27, 2010, 09:42:32 AM »
Thanks Blake!  That is in fact the same diagram on the under-hood label but mine is faded quite a bit.

My problem is that I don't know what is what on the TBI/manifold.  The label has ports listed F, J, C, and A; wondering what they are not that it matters (looks like I have them connected correctly) but wondering nonetheless.

Another problem is that I have no idea how the accessories are supposed to be hooked up or if the port on the back of the manifold is where they connect.  This is not a really big deal for the accessories (the cruise doesn't work for example) but I am trying to hook everything up right for now to eliminate any potential leaks and then when I can get around to fixing the little stuff the lines are already there.

Last, I'm searching to see if I have missed any vacuum connections on the motor to ensure I have stopped any potential leakers.


/r

Allen

Offline beastie_3

  • Senior Member
  • ****
  • Posts: 3170
  • Josh
    • My truck pics
Re: '87 350 w/TBI Vacuum line questions
« Reply #4 on: February 27, 2010, 04:36:15 PM »
I dont know if I missed it, but what is the reason all the lines and hoses are messed up in the first place? Did you buy the truck like that or a undocumented engine swap? Just curious.

Offline RMC_SS_LDO

  • Newbie
  • Posts: 45
Re: '87 350 w/TBI Vacuum line questions
« Reply #5 on: February 27, 2010, 08:36:20 PM »
I got the truck some time ago but just now getting into it.

No clue what the previous owner did, but original engine/tranny.  Looks like the cruise died so instead of fixing it, they just disconnected the linkage and butchered the vacuum lines.  Along the way, I guess they managed to disconnect other stuff or couldn't figure out how it was supposed to be connected.

Anyway, I managed to take it for a spin today.  Seems to be running better and doesn't hesitate when getting on the gas now.  Not sure what I fixed, other than the EGR which I wouldn't think would have much impact but it is running!


So is the rear manifold connection supposed to run the accessories? 

Also, is that breather thingy from the left side valve cover that's connected to the TB collar correct?


Thanks!

Allen