EGR ?

Went to the smog test place today, passed emissions test no problem, but fail the vac test on the egr. mech. told me it wasnt getting vac to the egr. Got thinking about it. when warmed up and running their shouldnt be any vacuum going to it,or should their be? Dont think so Or am i all wet.,,,,,Dale

Guess i should post this in the tech section, sorry im a newbie

No vacuum should be on EGR if so maybe a very light almost unnoticeable amount

The signal that operates the valve at the EGR port is vacuum, and sometimes the signal is controlled by one or two valves.

yo,

Great advice!

Here is the EGR Section in my site;

http://www.broncolinks.com/index.php?index=146

Testing; "...There shouldn't be any vacuum at the EGR valve at idle or any time your ass is under the hood fiddling with it, to put it plainly, except for perhaps a very light residual vacuum from the EVR. Check ALL of your vacuum lines FIRST, and the vacuum reservoir for leaks..." Source: by SigEpBlue

I forget how much you know already about the EGR system, comonents functions & locations as well as da Air Injection (AIR), Secondary Air Injection; Pump (Smog Pump), Thermactor Air Bypass (TAB) & Thermactor Air Diverter (TAD) Solenoids; Diverter, Check & Bypass Valves, Cross-Over Tube, etc.

http://www.broncolinks.com/index.php?index=416'>http://www.broncolinks.com/index.php?index=416

In both sections there are locations, function and testing info

Do you have a Trouble Code or CEL?

its a 91, right?

Think you know about A Self Test for Diagnostic Trouble Codes (DTCs) by buddy, BroncoJoe ?

http://broncozone.com/topic/14269-code-reader/page__p__74587entry74587

I run it around to heat the engine up and shift thru all gears incl Reverse.

then; turn off all accesories/lights, etc.

Do KOEO portion first

For Key On Engine Running (KOER) portion, the engine has to be @ normal operating temp.

Post any codes found here or look em up in my broncolinks.com site using the Search feature or in each section

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Use the VECI Label showing da Emission Vac Diagram on radiator to go thru the hoses for a leak

Vacuum Diagram is the same as the one on the core support or hood or air filter cover.

Source: by Ford motorcraftservice.com

http://www.motorcraftservice.com/vdirs/retail/default.asp?pageid=&gutsid=

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).

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VRESER is the Vacuum Reservoir Can (Tank); Location pic in an 89 5.0 (Adam Titled it as "This")

Source: by AdamDude04 & miesk5 at Ford Bronco Zone Forums http://broncozone.com/topic/19892-whats-this-hose/

ACV (Air Control Valve) is the TAD (Thermactor Air Diverter) Valve (AIR Bypass (AIRB) and AIR Diverter (AIRD) valve combinations)

Thermactor Air Bypass (TAB) Solenoid (SOL V) (AIRB) see http://www.broncolinks.com/index.php?index=416

Thermactor Air Diverter (TAD) Solenoid (SOL V) (AIRD) see http://www.broncolinks.com/index.php?index=9

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ACV (Air Control Valve) is the AIR Diverter (AIRD) valve; also called the TAD (Thermactor Air Diverter) Valve

AIR BPV is the AIR Bypass (AIRB) valve; also called the TAB (Thermactor Air Bypass) Valve

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MAP is da Manifold Absolute Pressure Sensor

EGR is Exhaust Gas Re-circulation Valve

EVP is EGR Valve Position Sensor

EVR is EGR Vacuum Regulator

FPR is Fuel Pressure Regulator;

Carbon Can is da Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister

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; pic in a 90 by Seattle Bronco at http://www.supermotors.net/registry/media/795183

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 via Steve83 at http://www.supermoto...ry/media/283481

Vapor Valve (V REST) pics in 5.0, 5.8, & 4.9...The smaller valve uses a thicker grommet to fit in the same hole as the larger one..." by Ford via Steve at http://www.supermoto...ry/media/767956

V REST on earlier years such as SEABRONC's 83 is a Vacuum Restictor/delay valve, it delays vacuum for a certain amount of time. See his Vacuum Line Diagram (modified to reflect changes He made) at http://www.supermoto.../media/672883_1

VCKV is Vacuum Check Valve

MAN VAC is Manifold Vacuum

CAT is the catalytic converter

ENG is the engine

PCV is Positive Crankcase Ventilation Valve

EFCA is Electronic Fuel Control Assembly/ (Fuel Pressure Regulator (FPR)

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more by our PAL SEABRONC & Steve83 (includes Carbureted Models)

SV CBV = Carborator Fuel Bowl Solenoid Vent Valve

LCV = EGR Load Control

WOT =Wide Open Throttle) Valve

HICV = Hot Idle Control Valve

IVV = Thermactor Idle Vacuum Valve

VRDV = Vacuum Delay Valve (VDV, VRDV, DV-TW)

VDV = Vacuum Delay Valve)

VRDV = Distributor ****** Delay Valve

DV-TW = Two Way Delay Valve)

HEAT VLV INT = Heat Vacuum Control Valve Intake, (next to carb)

In an 85;

Red = Main vacuum

Green = EGR function

Orange = Heat control Valve (exhaust & intake) (AKA heat riser but more complex)

Yellow = Distributor advance

White = EGR vacuum (source)

Black = Mainly used for the Evaporative emissions control

Black = Thermactor ACV or diverter valve

Blue = Throttle Kicker Solenoid (TKS) which sends vacuum to a vacuum motor to boost the idle a set amount

Pink = Thermactor Air Bypass Valve (BPV)

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by AsianSpanker

CL: Located in the air cleaner

A/CL DV: Air Cleaner Diverter Valve

A/CL BI MET: Air Cleaner Bi-Metallic Valve

A/CL CWM: Air Cleaner Cold Weather Modulator

ACV: Air Control Valve

AIR: Ford calls this the Thermactor, short for Thermal Reactor. CA vehicles are installed with it as standard. Air Injection Reaction is what it stands for.

AIR BPV: Air Bypass Valve (aka Thermactor Air Bypass TAB)

BV: Bowl Vent (on top of the float tanks)

CARB: Carburetor

CPRV: Canister Purge Valve

DIST:

EGR: Exhaust Gas Recirculator

EFCA:

FLTR: Filter

FPR: Fuel Pressure Regulator

IVV: Thermactor Idle Vacuum Valve

MAN VAC: Indicating Manifold vacuum-Vacuum source

MAP: Manifold Absolute Pressure

SOLV: Solenoid Valve

SV-CBV: Carburetor Fuel Bowl Solenoid Vent Valve

VAC:

VCKV: Vacuum Check Valve

V CK V: Vacuum Check Valve

VRDV: Distributor ****** Delay Valve

TVS: Throttle Valve Solenoid (aka Solepot, Dashpot)

TVV: Thermostatic Vacuum Valve (aka Ported Vacuum Switches)

PURGE CV: Vapor Canister Purge Valve

Color Codes to do Vacuum Diagram

Red = Main vacuum

Green = EGR function

Orange = Heat control Valve (exhaust & intake) (AKA heat riser but more complex)

Yellow = Distributor advance

White = EGR vacuum (source)

Black = Mainly used for the Evaporative emissions control

Black = Thermactor ACV or Diverter valve

Blue = Throttle Kicker control

Pink = Thermactor Air Bypass Valve (BPV)

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By WEBMASTER at http://www.fordtruck...read.php?t=1703

A/CL: Located in the air cleaner

A/CL DV: Air Cleaner Diverter Valve

A/CL BI MET: Air Cleaner Bi-Metallic Valve

A/CL CWM: Air Cleaner Cold Weather Modulator

ACV: Air Control Valve

AIR: Ford calls this the Thermactor, short for Thermal Reactor. CA vehicles are installed with it as standard. Air Injection Reaction is what it stands for.

AIR BPV: Air Bypass Valve (aka Thermactor Air Bypass TAB)

BV: Bowl Vent (on top of the float tanks)

CARB: Carburetor

CPRV: Canister Purge Valve

DIST:

EGR: Exhaust Gas Recirculator

FLTR: Filter

FPR: Fuel Pressure Regulator

IVV: Thermactor Idle Vacuum Valve

MAN VAC: Indicating Manifold vacuum-Vacuum source

MAP: Manifold Absolute Pressure

SOLV: Solenoid Valve

SV-CBV: Carburetor Fuel Bowl Solenoid Vent Valve

VAC:

VCKV: Vacuum Check Valve

V CK V: Vacuum Check Valve

VRDV: Distributor ****** Delay Valve

TVS: Throttle Valve Solenoid (aka Solepot, Dashpot)

TVV: Thermostatic Vacuum Valve (aka Ported Vacuum Switches)

PURGE CV: Vapor Canister Purge Valve

Color Codes to Vacuum Diagram

Red = Main vacuum

Green = EGR function

Orange = Heat control Valve (exhaust & intake) (AKA heat riser but more complex)

Yellow = Distributor advance

White = EGR vacuum (source)

Black = Mainly used for the Evaporative emissions control

Black = Thermactor ACV or Diverter valve

Blue = Throttle Kicker control

Pink = Thermactor Air Bypass Valve (BPV)

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Overview & Diagram; "...Secondary Air Injection system consists of a belt-driven Air Pump, single or dual AIR Diverter valve(s), an AIR Bypass valve, and AIR Bypass solenoids, air silencer/filter, Powertrain Control Module and connecting wires and vacuum hoses. The Belt-Driven Secondary Air Injection system provides either upstream/bypass air or upstream/downstream/bypass air. The number of these system configurations vary significantly with AIR Bypass and AIR Diverter valve combinations (Figure 179). 2. The PCM provides one or more signals that enable one or more AIR Bypass solenoids. 3. The AIR Bypass solenoids control one or more AIR Bypass valves and/or AIR Bypass Diverter Valves in order to route secondary air depending upon the specific configuration. 4. The belt-driven Air Pump is operational any time the engine is running..." read more

Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

"...The 2ndry air system is known to fail in a wide variety of ways. The check valves that prevent hot exhaust from entering the rubber hoses age, rust, leak, & crack open melting the plastic TAB & TAD valves, creating exhaust leaks that can damage other components, raising exhaust oxygen levels (setting lean codes or rich adaptive limit codes), and making rattling noises. The hard steel tubing between the exhaust & the check valve can rust or crack (especially the infamous "crossover tube" on the backs of V8 heads). The vacuum controls leak (including the coffee can reservoir on the R wheelwell) (Miesk5 NOTE, this is the Vacuum Reservoir (VRESER), it stores excess vacuum to prevent rapid fluctuations and sudden drops in a vacuum signal, such as during acceleration) get misrouted during other repairs, or the diaphragms rupture. The electronics that control the vacuum controls can fail electrically or mechanically, or the wires can be damaged. But all of these failures are either A) relatively cheap & easy to repair, or B) cheap & easy to prevent with normal inspection & maintenance..."

Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

http://www.supermotors.net/registry/media/589993

Jus got off work, sorry for not responding earlier, thanks to all for the info, gotta get my act together and give more vehicle info, im used to my harley forum where everybody knows about my ol POS , Yes Miesk5 its a 91 5.8 with auto trans, im going to do some reading befor i ask anymore ?s thanks again and ill let yall know what i come up with,,,Dale

Had the same problem on mine. take off the hose connected to the egr valve, with the engine off blow into the hose. if u hear air leaking, just find where and replace with vacumm tube. my check engine light was on and after i did this it went away, quick and easy fix hope it helps.

Got the bronc to pass smog today, Went tru all the test suggested by Miesk5 , found a somewhat loose wire on the EVR, other than that it all checked out ok. the Evr still showed it wasnt working at smog station,untill he put it on the treadmill,not required where i live in the mountians, once he got the tires spinning the sucker worked and passed smog, Guess i learned sumpin today,,,,Dale