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Vacuum line Diagram

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My vacuum lines are so messed up(mostly the smaller ones) and I can't find a diagram showing what goes where. If someone could post one it would help. '89 5.0

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yo Michael,


You are in luck; hurry and copy/print out the diagram from;

Vehicle Emission Control Information (VECI) Decal; Contains Vacuum Diagram & Calibration Parts List for 88 & UP.

On-Line for Free at Ford.

Click "Quick Guides" in left panel; S

croll to & CLICK VECI Labels "Provides Vehicle Emission Control Information (VECI) and a related calibration parts list."

Enter applicable info year, light truck, engine type & (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. Suggest Right Clicking this Hot Link & Open in New Window

Source: by Ford at http://www.motorcraftservice.com


by our PAL SEABRONC & Steve83 (includes Carbureted Models)

From TOP of Diagram at NOON position;


ACV (Air Control Valve) is the TAD (Thermactor Air Diverter) Valve (also called, AIR Bypass (AIRB) and AIR Diverter (AIRD) valve combinations) behind engine; location pic by SeattleBronco thermactor-tab-air-bypass-valve.jpg

Location pic w/intake man removed by Booba5185;


has yellow vac line to it

see my site for more Info, location & testing LINKS at http://www.broncolinks.com/index.php?index=416



MAN VAC is Manifold Vacuum from Tree atop intake manifold

Tree Location pic vacuum-4.jpg

Source: by Seattle FSB (SeattleFSB)


FPR is Fuel Pressure Regulator, see http://www.broncolinks.com/index.php?index=422


EGR is Exhaust Gas Re-circulation Valve see http://www.broncolinks.com/index.php?index=415



Thermactor Air Diverter (TAD) Solenoid (SOL V) (AIRD) see http://www.broncolinks.com/index.php?index=905Thermactor Thermactor Air Bypass (TAB) Solenoid see http://www.broncolinks.com/index.php?index=904


EVR is EGR Vacuum Regulator http://www.broncolinks.com/index.php?index=911


VRESER is the Vacuum Reservoir Can (Tank), also called coffee can due to shape; http://www.broncolinks.com/index.php?index=924



EGR Valve Position (EVP) not shown; http://www.broncolinks.com/index.php?index=414

V REST on later years is Vapor Valve (Roll-Over); Depictions & Location Diagrams in 5.0, 5.8, 7.5, & 4.9; "...All fuel tank vapor valves make use of a small orifice that tends to allow only vapor and not fuel to pass into the line running forward to the vapor storage canister. This assembly mounts directly to the fuel tank using a rubber seal. Fuel vapors trapped in the sealed fuel tank are vented through the orificed vapor valve assembly in the top of the tank. The vapors leave the valve assembly through a single vapor line and continue to the carbon canister for storage, until they are purged to the engine. The vapor valve assembly mounted on the top of the fuel tank is used to control the flow of fuel vapor entering the fuel tank vapor delivery line which conducts vapor forward to the canister in normal circumstances. If due to extreme conditions, excessive pressure is generated inside the tank, the purge port opens up, allowing fuel vapor to escape to the atmosphere, and stabilizes pressure inside the tank. The valve assembly has a head valve which prevents the fuel tank from overfilling during refueling operation. The valve assembly also has a spring supported float assembly, which prevents liquid fuel from entering the vapor delivery line during severe handling, steep grades or in the event of vehicle rollover. The fuel fill cap is sealed and includes a built-in pressure-vacuum relief valve. Fuel system vacuum relief is provided after 3.5 kPa (0.50 psi) and pressure relief after 11.0 kPa (1.6 psi). Under normal operating conditions, the fill cap operates as a check valve, allowing air to enter the tank as fuel is used, while preventing vapors from escaping the tank through the cap..." by Ford


Carbon Can is da Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister) see http://www.broncolinks.com/index.php?index=1002


MAP is da Manifold Absolute Pressure Sensor see http://www.broncolinks.com/index.php?index=138




Lines by Seattle Bronco; (miesk5 Note, many vac lines have prob been replaced by black colored hoses, so use Seattle's pics as references)

The Pink Vacuum Line goes from the TAB Solenoid (driver's side rear solenoid) to the passenger side (adjacent to the Vacuum Reservoir Can) and down to the bottom of the TAB (Bypass) Valve. Note that my Pink Vacuum line appears Yellowish in this pic and is not yet connected to the base of the TAB Valve as I was working up a solution at the time.

Here is a pic of my VECI (Vehicle Emissions Control Information) Label for a 1990 5.8L Bronco. Be advised that the ACV (Air Control Valve) is the TAD (Thermactor Air Diverter) Valve and the AIR BPV is the TAB (Thermactor Air Bypass) Valve. The VRESER is the Vacuum Reservoir Can where the red & black vacuum lines plug into and the EGR is actually the EVP (EGR Valve Position Sensor



CPRV is Canister Purge Solenoid Valve/ Canister Purge Solenoid (CANP) is controlled by the PCM to vent fumes from the charcoal canister to intake manifold only when the engine is running


VCKV is Vacuum Check Valve


CAT is the catalytic converter


ENG is the engine


PCV is Positive Crankcase Ventilation Valve http://www.broncolinks.com/index.php?index=150





also, Climate Control Vacuum Line Diagram in an 86 (similar to your yr)

Source: by Chris B (Blue, bronco boy) at http://chrisb.users.superford.org/Bronco/Misc/1986_EVTSM_Page_141.jpg



Vacuum Leak Test; On an idling engine check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose section. BEWARE of fab, belts, pulleys and hot engine/hoses.

On COLD ENGINE only, use propane torch w/rubber hose attached, UNLIT (have fire ext @ hand for all tests)

or spray carb cleaner, when it gets to the the leak the RPMs will rise.

Also check: vacuum hoses; intake manifold gasket & throttle body;


and line to & Cruise Control sys in 86-91


& Line to & the power brake booster, Master Cylinder & Booster


Vacuum Gauge Diagnosis by CRAIG


The vacuum gauge should show around 18-22 in-Hg @ idle & maintain a steady needle. Rev it up to ~2500 rpm, hold it steady, and you should see the needle drop, then slowly increase to a level close to the idle reading (though slightly lower is normal).

Suggest buying a vac gauge, best low cost test and MPG helper you can spend $ on;

pic; "...I have a vacuum gauge mounted right in the dash of my truck. I use it to also help determine the load my engine is under while driving, and to estimate fuel economy..."

Source: by William T at http://www.fordf150.net/images/mytruck/vacgauge.jpg




I wrote, "Hurry" because Ford appears to be selling or leasing all older year Ford vehicle info to HELMS, it's publisher for Repair Manuals and recently, as of last year the Build Sheet info letters that were once free.

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