What the heck are these vacuum lines for? --> 1987 Chevy Silverado V10 4x4

[Mike Phillips]

What the heck are these vacuum lines for? --> 1987 Chevy Silverado V10 4x4


For some of the regulars, you probably know I had to remove the engine in my truck to get the frame welded up.  See the thread here,

http://tinyurl.com/y7bybvyy


I have the engine installed and about 95% of everything hooked back up except I'm not sure what the vacuum lines in the pictures below are for and where they go?


First picture

I think this was originally located above the brake power booster. 




??

[Mike Phillips]

Picture 2



I think the black ball thing is a vacuum reservoir thingamajiggy?

Where should and how should it be connected?

[Mike Phillips]

Picture 3



The left hand side of the line in the above picture goes to the vacuum modulator on a Turbo 400 Short Shaft.  This truck came with a 700R4 and then my buddies over on Car Fix installed the tranny and the transfercase, (NP205), on an episode called

Street Mudder

They ran a line up to one of the other vacuum lines and grafted it in but I don't remember where and none of the pictures I took before removing the engine show clearly where it was hooked up.


?

[Mike Phillips]

Picture 4




There's this tiny or THIN vacuum line coming out of the firewall and it's broke and cracked.

Here's a close-up



What is it?

Where should it be hooked up?

Can I insert a slightly larger rubber line over it to make it functional?


?

[Mike Phillips]

Picture 6




Looks like some kind of vacuum diaphragm thingamajiggy?

What should be hooked up to it?  --> the tiny broken line coming out of the firewall?


?

[Mike Phillips]

Picture 7



What is this supposed have feeding off of it?

The tiny vacuum line coming out of the firewall?

How about hooking the vacuum line to the vacuum modulator that is on the Turbo 400 to this?


?

[Mike Phillips]

Any help will be greatly appreciated.

I know, everyone says...


You should have taken pictures or marked them



I did take pictures, just not enough "good" pictures.  And yeah, I should have marked them.  I thought I would remember...

Wait till my wife reads this and she'll tell you about my memory....


I'm going over to the shop tomorrow morning to install the new master cylinder.  I bench bled it yesterday and was letting it sit overnight and I'll bench bleed it again tomorrow morning before installing.

After that it's time to add water to the cooling system, power steering fluid to the power steering pump, install the batter and test fire the engine.

The hope is she fires right up and purrs like a kitten.  If so, then I bleed the brakes, install the hood and driver her home.

But at some point tomorrow morning I have to figure out the rest of the vacuum lines and the two wires in this thread,

http://forum.73-87chevytrucks.com/smforum/index.php?topic=35254.0


So any help or suggestions will be greatly appreciated.

Snide remarks will be deserved and I'm pretty good at taking a joke and laughing at myself...

[Stewart G Griffin]

Pic 3 likely goes to pic 7.

But do you have an emmissions sticker on the radiator core support?

[bd]

Mikey, Mikey, Mikey.

• Fig 1 (the hose in your hand) connects to Fig 3, which then together connect to Fig 7 (manifold vacuum). 
  
  
• Fig 2 (HVAC vacuum reservoir) connects to the tee in Fig 1 and the 1/8" spaghetti line in Figs 4 & 5.  The barrel shaped plastic tee in Fig 1 is a vacuum check valve that helps maintain vacuum in the HVAC reservoir.  The capped port on the check valve would have connected to a factory cruise control actuator (vacuum motor) if the vehicle had cruise control.
  
  
• Fig 6 is the EGR valve that connects to the EGR solenoid, which shares a mounting bracket with the ESC module, just to the right of the IAC and TPS on the TBI throttle body.
  

Was that clear as mud?

[Mike Phillips]

Pic 3 likely goes to pic 7.

Copy that.

This would be a "new" vacuum line for this truck since it never had a vacuum modulator from the factory.

I'll need to get a vacuum T so I can add VM vacuum line to this factory engine.

But do you have an emmissions sticker on the radiator core support?

Yes.  I used it to reconnect what it shows but it doesn't show all vacuum lines.

Thank you for your help

[Mike Phillips]

Mikey, Mikey, Mikey.

Fig 1 (the hose in your hand) connects to Fig 3, which then together connect to Fig 7 (manifold vacuum). 

Got it.  Going to NAPA after I finish this reply and will pick up a new vacuum T

Fig 2 (HVAC vacuum reservoir) connects to the tee in Fig 1 and the 1/8" spaghetti line in Figs 4 & 5. 

Got it.

The barrel shaped plastic tee in Fig 1 is a vacuum check valve that helps maintain vacuum in the HVAC reservoir.  The capped port on the check valve would have connected to a factory cruise control actuator (vacuum motor) if the vehicle had cruise control.

Copy that.  Truck does not have cruise control.

Fig 6 is the EGR valve that connects to the EGR solenoid, which shares a mounting bracket with the ESC module, just to the right of the IAC and TPS on the TBI throttle body.

I'll have to look and double check for a vacuum port on the EGR Solenoid and if I find one, then I'll run a vacuum line from it to the EGR Valve.

Was that clear as mud?

Yes.  Very well explained.

Thank you.

[Mike Phillips]

Okay - I feel confident I have all the vacuum lines sorted, routed and connected.

Thank you everyone for your help.




Sent from my iPhone using Tapatalk

[VileZambonie]

Use your phone to take before pix 

[Stewart G Griffin]

Pic 3 likely goes to pic 7.

Copy that.

This would be a "new" vacuum line for this truck since it never had a vacuum modulator from the factory.

I'll need to get a vacuum T so I can add VM vacuum line to this factory engine.

But do you have an emmissions sticker on the radiator core support?

Yes.  I used it to reconnect what it shows but it doesn't show all vacuum lines.

Thank you for your help

i was going to ask about that last night but ran out of time.   Do Th-400's use vacuum modulators?

[Stewart G Griffin]

Not sure how i ended up at the below site because i'm falling asleep, but you may want to scroll down.....:

http://www.gmsquarebody.com/threads/exhaust-gas-recirculation-egr-system-1989-tbi.6902/