Vacuum Tree to Nowhere

Hello,

I'm restoring this 1988 Ford Bronco Custom with a 302 engine and C6 transmission. While repairing a lot of the damaged vacuum hoses, I noticed what looks like a vacuum tree attached near the windshield wipers in the engine compartment. There are three attachments, one is capped, one is empty, and one has a vacuum line that leads to nowhere. There are similarly cut vacuum lines that appear to maybe connect, one of which leads to the charcoal filter.

If anyone could help me out, it would be greatly appreciated. I plan on re-doing all the vacuum hoses soon, but I'd like to know where everything goes first.

Thanks,

Tyler

yo TYLER,

88 XLT 351W C6 Vacuum Tree Pic by Saltlife (Tree factory location is on the firewallfirewallon 

Vehicle Emission Control Information (VECI) Decal,
for 88 & UP.
On-Line for Free at Ford.
Click "Quick Guides" in left panel;
Scroll to & CLICK VECI Labels "Provides Vehicle Emission Control Information (VECI) and a related calibration parts list." Enter applicable info (need to know your Calibration number from your B-pillar sticker).
Vacuum Diagram is the same as the one on the core support or hood or air filter cover.
Source: by Ford http://www.motorcraftservice.com
 

and one from a Bronco buddy;

 

Vacuum Line Routing Diagram in a 88 5.0
Source: by Jem270 http://www.supermotors.net/registry/media/231746_1

 

 

Vacuum Line Acronyms, leak test & gauge pic OCT 2013

http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/

by Seabronc (Rosie, Fred W), Seattle FSB & miesk5 at Ford Bronco Zone Forums

Scroll to Post #20

 

Vacuum Line R&R by Booba5185 in an 89 F150

:...This should cover most 87-96 V8s (302\351)..."His 89 has tree on intake manifold.

 

And by Seabronc elsewhere, "...There should be a vacuum tree located near the rear of the intake manafold with a line running directly from it to the C6 vacuum modulator. Depending on features installed, the line to the C6 may be tapped off a line supplying vacuum to other devices. The bottom line, for the C6 anyway, is that it needs to be supplied by Main Vacuum..."

 

 

"...Use "Hard (Heavy Duty)" vacuum line for booster. Regular rubber hose such as used for WS washer fluid line will likely collapse after about say, 20 years. Inspect for any sign of kinking or collapse. Check vacuum draw available with a gauge connected between engine and booster. At idle, healthy engines draw somewhere between 17 and 22 in Hg. Check vacuum by depressing brake pedal firmly until it stops. The gauge should read a drop to approximately 10 in. Hg and then quickly recover to a normal reading. If vacuum takes too long to recover, there is a restriction in the volume, i.e.: fitting clogged or vacuum hose collapsed. Repair as necessary. While a defective booster will cause a hard pedal, a spongy or low pedal requires a hydraulic system check..."
Source: by miesk5 at Ford Bronco Zone Forums

 

HVAC VACUUM Harness;

Huh alright. Thanks so much!

Have a good one and I'll be sure to post pictures when it's done!

Tyler

My mistake.. the engine is actually a 351 5.8L. Don't know if that would change things.

Tyler

Alright well lo and behold I've found yet another broken vacuum line. It attaches to the back left of the engine if you were at the front of the vehicle looking in. Came with a complimentary ***** stuck in the hose to maintain vacuum.

Also if I take the ***** out and start it, it works but there's a large amount of suction.

It is a 351 Windsor 5.8 liter engine.

yo Tyler,

The vacuum line that attaches to the back left of the engine is most likely the

Air Bypass Valve (AIR BPV)

In the https://www.motorcraftservice.com link I gave you, if you go thru the drill, you'll see the AIR BPV @ top of the vacuum diagram

https://www.motorcraftservice.com/pubs/auxf/~WC/USENIE/1858/E8AEAGA.gif for example for 1988  5.8 CALIBRATION: 8-64E-R00; 

It travels to the Thermactor Air Bypass Solenoid (TAB, AIRB, AM1) next to ignition coil

.http://www.supermotors.net/getfile/848247/thumbnail/tab-tad-evr-coil2a.jpg

It may have the Thermactor Air Diverter) Valve (TAD) attached to it in the 5.8; if so TAD line goes to the Thermactor Air Diverter Solenoid (TAD, AIRD, AM2) next to TAB

See these pics;

  by Seattle Bronco



by Steve

In the Ford diagram,

ACV (Air Control Valve) is the TAD (Thermactor Air Diverter) .

VRESER is the Vacuum Reservoir Can;

TAB/ TAD Valve located at the rear of the Intake Manifold. You have to climb up onto the engine to feel the Diverter Valve or remove the Intake Manifold. I'd rather climb up using planks, ala a scaffolding type set-up; maybe remove hood depending on circumstances such as me now, w/ backache..."
 

Without reading through the entire post, that tree usually hooks to  the vacuum tree behind the carb,  with one line going to the transmission vacuum modulator and one going to the vacuum reserve tank system.  If you are not using all the ports on the vacuum tree then you can eliminate it and just hook the transmission vacuum modulator to the tree and if you have the reserve tank system, it can also be hooked directly to the tree.

>-

I just realized that this is an EFI engine, but the comment above about the vacuum tree still stands, and you should have a vacuum reserve tank system. The reserve system keeps the vent system from dropping out when you create low vacuum situations, as in excelleration, going up hills, etc.