EMISSION CONTROLS-EXHAUST SYSTEMS
4A-1EMISSION CONTROLS-EXHAUST SYSTEMSPage4A-1Emission ControlsPage4A-36Exhaust SystemsEMISSION CONTROLSAir Guard SystemCatalytic ConverterEGR SystemEmission ComponentsEmission Control MaintenanceEngine ModificationsFuel Tank Vapor Emission Control SystemPage4A-74A-164A-114A-404A-274A-1O4A-1 7GENERALEmission control systems are required to meet existing standards for exhaust, crankcase, and raw fuel vapor emissions. The systems control emission ofhydrocarbons, carbon monoxide, and oxides of nitrogenat the levels specified by Federal or Ca]iforniastandards.Federal Emission Standards and the standards whichapply in California differ. This necessitates a number ofdifferences between emission control systems on ye-Page4A-204A-14A-374A-214A-244A-384A-23PCV SystemService Diagnosis GuideSpecificationsTAC SystemTCS SystemTuneup SpecificationsVTM Systemhides built for sale in California and in the remaining 49states.Emission control system usage varies in re]ation toengine, transmission, and series application. The Emission Control Systems Application Chart at the end ofthis section may be used to determine the current system usage for any particular vehicle.This section outlines service procedures for a]] JeepEmission Control Systems. Tuneup specifications andprocedures as prescribed by the U.S. Emission ControlServices Maintenance Chart are also included.Service DiagnosisThe following table lists causes of service problems in descending order of probability. It is more likely a problem results from the first listed ‘possiblecause" than the tenth, for instance.However, visual examination often leads directly to the correct solution and all service procedures should begin with a careful look at anysuspected part or assembly.ConditionHARD STARTINGENGINE CRANKSNORMALLYPossible CauseCorrection1Binding linkage, choke valve orchoke piston.1Repair as necessary.2Initial choke valve settinginc orrect.2Adjust initial choke valvecorrectly.3Restricted choke vacuum andhot air passages or disconnectedvacuum hose.3 Clean passages or connect4Improper fuell level.45Dirty, worn or faulty needlevalve and seat.5 Repair as necessary.vacuum hose.Adjust float level.70494A
4A-2 EMISSIONS CONTROLS-EXHAUST SYSTEMS1Service Diagnosis ContinuedConditionHARD STARTINGENGINE CRANKSNORMALLYContinuedPossible Cause6Float sticking.6Repair as necessary.7Exhaust manifold heat valve stuck.7Repair as necessary.8Faulty fuel pump.8Replace fuel pump.9Incorrect choke cover adjustment.9Adjust choke cover.10Inadequate unloader adjustment.10Adjust unloader.11Faulty ignition coil.11Test and replace as necessary.12Improper spark plug gap.12Adjust gap.13Incorrect initial timing.13Adjust timing.14Check valve timing; repair asnecessary14 Incorrect valve timingROUGH IDLE ORSTALLINGCorrection1Incorrect curb or fast idle speed.1Adjust curb or fast idle speed.2Faulty EGR valve operation.2Test EGR system and replace asnecessary.3 Vacuum leak.3Check manifold vacuum andrepair as necessary.4Improper choke setting.4Adjust choke.5Improper fast idle cam adjustment.5Adjust fast idle.6Choke binding.6Locate and eliminate bindingcondition.7Improper idle mixture adjustment.7Adjust idle mixture.8Faulty TAC unit or disconnectedTAC hose.8Repair as necessary.9Damaged tip on idle mixturescrews.9Replace mixture screws.10Improper fuel level.10Adjust fuel level.11Incorrect initial timing.11Adjust timing to specifications.12Faulty distributor rotor or cap.12Replace rotor or cap.13Secondary throttle valves notclosing 4350 Model, 4Vcarburetor.13Locate and eliminate bindingcondition.14Exhaust manifold heat valveinoperative.14Lubricate or replace heat valveas necessary.15Test PCV valve and replace asnecessary.15 Faulty PCV valve air flow.704948
vuEMISSIONS CONTROLS-EXHAUST SYSTEMS 4A3Service Diagnosis ContinuedConditionROUGH IDLE ORSTALLING ContinuedFAULTY LOW-SPEEDOPERATIONFAULTYACCELERATIONPossible CauseCorrection16Leaking engine valves.16Check cylinder leakdown rate orcompression and repair as necessary.Check wiring and correct asnecessary.17Incorrect ignition wiring.1718Faulty coil,.18Test coil and replace as necessary.19Clogged air bleed or idle passages.19Clean passages.20Restricted air cleaner.20Clean or replace air cleaner.1Clogged idle transfer slots.1Clean transfer slots.22Clean air bleeds and passages.3Restricted idle air bleeds andpassages.Restricted air cleaner.3Clean or replace air cleaner.4Improper fuel Level.4Adjust fuel level.5Faulty spark plugs.5Clean or replace spark plugs.6Dirty, corroded, or loose secondarycircuit connections.6Clean or tighten secondary circuitconnections.7Faulty ignition cable7Replace ignition cable.8Faulty distributor cap.8Replace cap.1Improper pump stroke.1Adjust pump stroke.2Incorrect ignition timing.2Adjust timing.3Inoperative pump dischargecheck ball or needle.3Clean or replace as necessary4Worn or damaged pump diaphragmor piston.4Replace diaphragm or piston5Leaking main body cover gasket.5Replace gasket.6Engine cold and choke too lean.6Adjust choke.7Improper metering rod adjustmentYF Model cariburetor or 4350Model carburetor.7Adjust metering rod.8Faulty spark plugs.8Clean or replace spark plugs.9Leaking engine valves.9Check cylinder leakdown rate orcompression, repair as necessary.10Faulty coil.10Test coil and replace as necessary.70494C
4A-4 EMISSIONS CONTROLS-vuEXHAUST SYSTEMSService Diagnosis ContinuedFAULTY HIGHSPEED OPERATIONCorrectionPossible CauseCondition1Incorrect ignition timing.1Adjust timing.2Faulty distributor vacuumadvance.2Check vacuum advance and repairas necessary.3Faulty distributor centrifugaladvance.3Check centrifugal advance andrepair as necessary.4Defective TCS system.4Test TCS System; repair asnecessary.5Low fuel pump volume.5Replace fuel pump.6Improper spark plug gap.6Adjust gap.7Faulty choke operation.7Adjust choke.8Partially restricted exhaustmanifold, exhaust pipe, muffler,or tailpipe.8Eliminate restriction9Incorrect valve timing.9Check valve timing and repair asnecessary10Improper size or obstructed mainjets.10Clean or replace as necessary.11Clogged secondary meteringpassages 4350 V4 carburetor.11Clean passages.12Restricted air cleaner.12Clean or replace as necessary.13Secondary linkage, throttle valves,or shaft binding 4350 4Vcarburetor.13Locate and eliminate bindingcondition14Auxiliary inlet valve not adjustedproperly 4350 4V carburetor.14Adjust inlet valve.15Faulty distributor rotor or cap.15Replace rotor or cap16Intake manifold restricted.16Pass chain through passages.17Faulty coil.17Test coil and replace as necessary.18Leaking engine valves.18Check cylinder leak dpwn orcompression and repair asnecessary.19Faulty valve springs.19Inspect and test valve springtension and replace as necessary.20 Clogged vacuum passages.20Clean passages.21 Worn distributor shaft.21Replace shaft.70494D
-vuEMISSIONS CONTROLS-EXHAUST SYSTEMS 4A-5Service Diagno.is ContinuedPossible CauseConditionMISFIRE AT ALLSPEEDSPOWER NOT UPTO NORMALCorrection1Vacuum leak.1Check manifold vacuum andrepair as necessary.2Faulty spark plugs.2Clean or replace spark plugs.3Faulty spark plug cables.3Replace as necessary.4Faulty distributor cap or rotor.4Replace cap or rotor.5Distributor trigger wheel set toohigh.5Set trigger wheel to specification.6Faulty coil.6Test coil and replace as necessary.7Primary circuit shorted or openintermittently.7Trace primary circuit and repairas necessary.8Leaking engine valves.8Check cylinder leakdown rate orcompression and repair as necessary.9Faulty hydraulic tappets.9Clean or replace tappets.10Faulty valve springs.10Inspect and test valve springtension, repair as necessary.11Worn lobes11Replace camshaft.12Improper carburetor settings.12Adjust carburetor.13Fuel pump volume or pressurelow,13Replace fuel pump.14Blown cylindLe:r head gasket.14Replace gasket.15Intake or exhaust manifoldpassages restricted.15Pass chain through passages.Oflcamshaft.1Incorrect ign:it:ion timing.1Adjust timing.2Faulty distributor rotor.2Replace rotor.3Distributor trigger wheel set toohigh.3Set trigger wheel to specification.4Incorrect spark plug gap.4Adjust gap.5Faulty fuel pu:mp.5Replace fuel pump.6Incorrect valve timing.6Check valve timing and repairas necessary.7Faulty coil.7Test coil and replace as necessary.8Faulty ignition.8Test cables and replace asnecessary.9Leaking engine valves.9Check cylinder leakdown rate orcompression and repair as necessary.10Blown cyiinde:r head gasket.10Replace gasket.11Leaking piston rings.11Check compression and repair asnecessary.70494E
4A-6 EMISSIONS CONTROLS-viEXHAUST SYSTEMSService Diagnosis ContinuedPossible CauseConditionINTAKE BACKFIREEXHAUST BACKFIREPING ORSPARK KNOCK1Lean fuel mixture.1Check float level or manifoldvacuum for vacuum leak.23Improper ignition timing.2Adjust timing.Faulty accelerator pump discharge.3 Repair as necessary.4Improper choke operation.4Repair as necessary.5Defective EGR CTO5Replace EGR CTO6Defective TAC unit.6Repair as necessary.1Vacuum leak.12Faulty diverter valve.23Faulty choke operation.3Check manifold vacuum and repairas necessary.Test diverter valve and replaceas necessary.Repair as necessary.4Exhaust leak.4 Locate and eliminate leak.1Incorrect ignition timing.Distributor centrifugal or vacuumadvance malfunction.12Adjust timing.Check advance and repair asnecessary.3Use combustion chamber cleaner.4Excessive combustion chamberdeposits.Carburetor set too lean.4Adjust carburetor.5Vacuum leak.56Excessively high compression.7Fuel octane rating excessively low.8Heat riser stuck in heat onposition.8Free-up or replace heat riser.1Low fuel level.1Adjust fuel level.2Low fuel pump pressure or volume.2Replace fuel pump.3Metering rods not adjustedproperly Model YF Carburetor,Model BBD Carburetor, or Model4350 Carburetor.3Adjust metering rods.4Improper PCV valve air flow.4Test PCV valve and replace asnecessary.5Vacuum leak.5Check manifold vacuum andrepair as necessary.6Clogged main jets.6Clean main jets.7Undersize main jets7Replace main jets.8Blocked air bleeds.8Clean air bleeds.9Clogged fuel filter screen.9Replace fuel filter.23SURGING CRUISINGSPEEDS TOTOP SPEEDSCorrectionCheck manifold vacuum andrepair as necessary.6 Check compression and repairas necessary.7 Try alternate fuel source.70494 F
vuEMISSIONS CONTROLS--EXHAUST SYSTEMS 4A-7AIR GUARD SYSTEMPage4A-1O4A-7Air Injection Manifolds and TubesAir PumpPage4A-94A-7DiverterGeneralGENERALAIR INJECTIONMANIFOLDThis system incorporates a belt driven air pump, diverter bypass valve, air injection manifolds and connecting hoses fig. 4A-1 and 4A-2.Air is discharged from the air pump to the divertervalve which directs it to the air distribution manifoldsor dumps it through a bypass port, depending on engineoperating conditions. Air pressure in this system is keptto approximately 5 psi by a relief valve incorpo:rated inthe diverter valve.Air is routed through the air injection manifold intothe engine exhaust ports. The air mixes with hot unburned exhaust products and causes a further burningof the mixture, reducing hydrocarbon and carbon monoxide emissions to the atmosphere.DIVE RTER VALVETO-AIR INJECTIONVACUUM SENSINGLINE TO MANIFOLDVACUUMAIR PUMPThe air pump used for V-8 and six-cylinder engines isthe same. A pump with a smaller diameter pulley isused on V-8 engines with altitude compensation. Themajor components of the air pump are enclosed in a diecast aluminum housing. A filter fan assembly, rotorshaft and drive hub are visible on the pump exterior fig.4A-3.AIR INJECTIONMANI FOLDAl R PUMP-TODIVERTER VALVEHOSE43040Fig. 4A-1 Air-Guard System-SIx-CyiinderHOSE DIVERTERVALVE-TO-AIRINJECTION MANIFOLDAJ42006Fig. 4A-2 Air-Guard System-V-8REAR COVERVENT HOLEDO NOT OIL‘V./HOUSINGrROTOR SHAFT ANDDRtVE HUB42007Fig. 4A-3 Air Pump
4A-8 EMISSIONS CONTROLS-vuEXHAUST SYSTEMSThe pump is designed for long life and is serviceableonly by replacement. It is not recommended that therear housing cover be removed for any reason, since theinternal components of the pump are not serviceable.The aluminum housing has cavities for air intake,compression and exhaust and a bore for mounting thefront bearing. The housing also includes cast meteringareas that reduce the noise of intake and compression.Mounting bosses are located on the housing exterior.NOTE: The relief valve assembly is incorporated in thediverter valve. If defective, the diverter valve assemblymust be replaced.The front bearing supports the rotor shaft. The bearing is secured in position by plastic, injected aroundgrooves in the housing and bearing outer race.The rear cover supports the vane pivot pin, rear bearing race and exhaust tube. Dowel pins pressed into thehousing correctly position the end cover which is fastened by four bolts.The rotor positions and drives the two vanes. Astamped steel liner supports carbon shoes and shoesprings which seal the vanes and rotor. The two plasticvanes are molded to hubs which support bearings thatrotate on the pivot pin. The pulley drive hub is pressedon the rotor shaft, and bolt holes in the hub provide forattachment of a pulley.The pump vanes are located 180 degress apart androtate around the pivot pin which is located on thecenterline of the pump housing. The rotor which drivesthe vanes rotates off the centerline of the pump housingfig. 4A-4. This creates changes in the distance betweenthe outside of the rotor and the inner wall of the pumphousings during rotor rotation. As the leading vanemoves past the intake opening, it is moving from a smallarea to a large area defined by the rotor-to-pump housing clearance. This forms a vacuum which draws airinto the pump. As the vanes and rotor continue to rotate, the trailing vane passes the intake and traps the airbetween the vanes. The vanes and rotor move into smallarea and the entrapped air begins to be compressed. Thecompression continues until the leading vane passes theexhaust opening where the compressed air passes out ofthe pump and on to the rest of the Air Guard INE OF PUMP BOREAND AXIS OF VANE ROTATIONThe air pump is not completely noiseless. Under normal conditions, noise rises in pitch as engine speed increases. Allow for normal break-in wear of the pumpprior to replacement for excessive noise.First check the drive belt tension and tighten as specified. Do not pry on the aluminum housing. Check hosesto be sure they are properly connected and are in goodcondition and check that the pump mounting bracket issecurely fastened.Air pump noise can be confused with other enginenoise. On a noise complaint, first remove the drive beltand check the pump to make sure it is operative. Aseized pump will not rotate and the noise could becaused by belt slippage.A chirping or squeaking noise probably originatesfrom vane rub in the housing bore and is noticeable atlow speed intermittently. Vane chirping is often eliminated at increased pump speeds, or with additionalwear-in time.Bearing noise is easily distinguished from vane chirping. It is a rolling sound noticeable at all speeds. It doesnot necessarily indicate bearing failure. If bearing noisereaches an objectionable level at certain speeds, thepump may have to be replaced.Failure of a rear bearing is identified by a continuousknocking noise and replacement of the pump is required.If it is determined that the air pump is not deliveringair determine presence of airflow by removing an exhaust hose, the pump must be replaced.NOTE: The pump is equipped with a centrifugal fantype air filter, located behind the drive pulley. In theevent that the engine or underhood compartment is to becleaned with steam or high-pressure detergent, the filtershould be masked off to prevent liquids from enteringthe pump.Service PrecautionsThe following is a list of service precautions to preventdamage to the air pump. DO NOT:* Attempt to prevent pulley from rotating by inserting tools into the centrifugal filter fan.* Operate engine with pump belt removed or disconnected except for noise diagnosis.* Attempt to lubricate.* Clean centrifugal filter.* Disassemble pump or remove rear cover.* Exceed 20 foot-pounds torque on mounting bolts.* Pry on aluminum housing to adjust belt tension.* Clamp pump in vise.Removal-Six-cylInderAJ42008Fig. 4A-4 AIr Pump OperationAir Pump Diagnosis1 Disconnect air pump output hose at back of airpump.2 Loosen adjustment bolt and remove drive belt.
viEMISSIONS CONTROLS3 Remove front mount bracket-to-engine attaching bolts.4 Remove rear mount bracket-to-pump attachingbolts.5 Loosen rear mount bracket-to-power steeringattaching bolts.6 Pull pump down and forward to remove.Installation-Six-Cylinder1 Position pump and install rear mount bracketto-pump attaching bolts.2 Install front mount bracket-to-engine attachingbolts.3 Tighten attaching bolts to specified torque.4 Adjust power steering drive belt to specifiedtension.5 Connect air pump output hose to back of pump.6 Adjust air pump drive belt to specified tension.-EXHAUST SYSTEMS 4A-9This moves the metering valve down against its upperseat and away from its lower seat, forcing air pumpoutput to vent to atmosphere fig. 4A-5. Air pump output is diverted only momentarily because of a bleed holein the diaphragm. This hole allows vacuum to quicklyequalize on both sides of the diaphragm and the diaphragm spring returns the metering valve to its normalposition.If the air pump develops excessive output pressure,this pressure will overcome the diaphragm spring tension, pushing the metering valve down and ventingpump output pressure to the atmosphere. When pumpoutput pressure returns to normal, the metering valvewill move up and away from the upper seat and againstthe lower seat, returning to its normal open position,allowing air pump pressure to flow to the SENSINGINLETDisconnect air pump output hose at pump.Loosen mount bracket-to-pump attachingand remove drive belt.Remove mount bracket-to-pump attachingRemove pump.Installation-V-81 Position pump at mounting location and installmount bracket-to-pump attaching bolts do not tighten.2 Install drive belt and adjust to the specifiedtension.3 Tighten mounting bolts and adjusting strapscrew to 20 foot-pounds torque.OUTLETTO AIRINJECTIONMANIFOLDNOTE: If air pump is driven by the air conditioningbelt, adjust the belt to the tensiov specified for the airconditioning belt. Pry only against the cast iron coverwhen adjusting the belt. Do not pry on the aluminumDIVERT ANDPRESSURERELIEF OUTLETMETERINGVALVE INBYPASSPOSITIONA50277housing.DI VENTER BYPASS VALVEA diverter valve is used in all Air Guard applications.The valves for V-8 and six-cylinder engines differ only inthe number of outlets. The V-8 diverter valve has twooutlets and the six-cylinder diverter valve has only one.The valve momentarily diverts air pump output fromreaching the exhaust during rapid deceleration and actsas a pressure release when air pump output is excessive.An internal silencer is incorporated in the diverter housing to muffle the airflow.In a rapid deceleration condition, high intake manifold vacuum is applied to the diaphragm in the diverter.When the vacuum signal is 20 inches of mercury ormore, the spring tension of the diaphragm is overcome.INLETFROMAIRPUMPFig. 4A-5 Diverter VaiveDiverter Test1 Start engine and let idle.2 Check diverter vents. Little or no air should flowfrom vents.3 .Accelerate engine to 2000 to 3000 rpm and rapidly close throttle. A strong flow of air should pass fromthe diverter vents for approximately 5 seconds. Thehigh-flow diverter used on some engines should vent forapproximately 3 seconds. If air does not flow or if backfire occurs, make certain vacuum sensing line has vacuum and is not leaking.
EXHAUST SYSTEMS-vuNOTE: The diverter valve diverts air pump outputNOTE: Some resistance to removal may be encounwhen 20 inches of Hg or more is applied at vacuumsensing line or pump output exceeds 5 psi 8 psi on someni odels.tered due to carbon build-up on screws.4A-1O EMISSIONS CONTROLS-4 Slowly accelerate engine. Between 2500 and 3500rpm, air should begin to flow from diverter vents.Diverter ReplacementThe diverter valve is not serviceable and must bereplaced if defective. The valve is attached to a bracketor suspended by the hoses between the air pump and airinjection manifolds fig. 4A-1 and 4A-2. Removal involves disconnecting the hoses and the vacuum sensingline and bracket clamp, if equipped. Installation involves reconnecting the hoses and vacuum line and attaching the bracket clamp, if equipped.3 Remove air injection manifold.Installation-Six-Cylinder1 Assemble air injection manifold and screws toexhaust manifold. Tighten screws to 20 foot-poundstorque.2 Connect air delivery hose to check valve.Removal-V-81 Disconnect air delivery hose at check valve.2 Remove injection screws.NOTE: Some interference to removal may be encountered due to carbon buildup on the screws.AIR INJECTION MANIFOLDSThe air injection manifolds are constructed of coldrolled steel with a zinc plating and distribute air fromthe pump to the exhaust ports.A check valve, incorporating a stainless steel springplunger and an asbestos seat, is integral with the airinjection manifold. Its function is to prevent the reverseflow of exhaust gases to the pump during pump failureor diverter valve bypass operation. Reverse flow woulddamage the air pump and connecting hoses.The distribution tubes of the air injection manifoldare connected directly to the exhaust manifolds. Thehollow attaching screws conduct airflow into the exhaust manifolds. Air distribution tubes are used for allcylinders except No. 7 on V-8 engines.3 Remove air injection manifold.4 Remove sealing gaskets from air injectionmanifold.lnstallation-V-81 Install air injection manifold using a replacement sealing gasket at either side of each opening.2 Install screws to exhaust manifold. Tightenscrews to 38 foot-pounds torque.3 Connect air delivery hose.Check Valve TestRemoval-Six-Cylinder1 Disconnect air delivery hose at check valve.2 Remove injection screws from each cylinder exhaust port.To check the air injection manifold valve for properoperation, disconnect the air supply hose at the injectionmanifold. With the engine running above idle speed,listen and feel for exhaust leakage at the check valve. Aslight leak is normal.ENGINE MODIFICATIONSThe design of certain engine components is directlyrelated to emission standards. The operation of suchitems as the camshaft, carburetor, ignition distributorand cylinder head affects the amount of emissions.Therefore, the correct combination of engine components, as prescribed by government certification,must be used in service. Refer to the appropriate sections of this manual for servicing these components.
-EMISSIONS CONTROLSvi-EXHAUST SYSTEMS 4A-1 1EXHAUST GAS RECIRCULATION EGR SYSTEMPage4A-134A-154A-1 1EGR CTO SwitchEGR Delay ValveEGR ValveGENERALPage4A-144A-1 14A-15Exhaust Back-Pressure Sensor-Non-IntegralGeneralRestrictor PlatesEGR VALVEThe EGR Exhaust Gas Recirculation system. used onall Jeeps reduces the formation of oxides of nitrogenNOx by introducing a metered amount of exhaust gasinto the combustion chambers. Exhaust gas is inert, willnot burn, and therefore combustion temperatures arereduced. Fewer oxides of nitrogen are produced at lowercombustion temperatures.Jeep vehicles for 1977 use three different types ofEGR systems fig. 4A-6, 4A-7 and 4A-8. The EGR system with no back-pressure sensor is used o:n all 49state Cherokee, Wagoneer and Truck models. The EGRsystem with integral back-pressure sensor is used onall California Cherokee, Wagoneer and Truck modelsand all CJ models except California 304 V-8 with manualtransmission. The EGR system with external, non-integral back-pressure sensor is used on California CJmodels with 304 V-8 and manual transmission.The EGR CTO switch prevents EGR action until engine temperature reaches a preset levl, and the backpressure sensor permits EGR action only at increasedengine loads, improving driveability.41263AFig. 4A-7 EGR System-V-8-TypicalEXHAUST BACKPRESSURE SENSOREGR PORTEGR VALVEBACK-PR ESSURESENSOR INTEGRALON MOST MODELSCARBURETOR EGR PORTAJ41263BINNERS-PORTFig. 4A-8 EGR System-V-8-CaliforniaCJ 304 Manual TransmissionCTOEGR VALVEFRONT42014Fig. 4A-6 EGR System-Six-Cylinder-TypicalThe EGR valve mounts on a machined surface at therear of the intake manifold on V-8 engines and on theside of the intake manifold on six-cylinder engines.When the separate back-pressure sensor is used, theEGR valve mounts on the spacer which is an integral
4A-12 EMISSIONS CONTROLSvuEXHAUST SYSTEMS-part of the back-pressure sensor. Exhaust gas is drawnfrom the exhaust crossover passage in V-8 engines, froman area near the heat riser in six-cylinder engines.EGR Valve without Integral Back-Pressure SensorEGR valves are calibrated by the use of differentlyshaped pintles fig. 4A-9. The valve is normally heldclosed by a spring located above the diaphragm fig. 4A10. The valve opens when sufficient vacuum is appliedthrough hoses connecting the CTO switch and the backpressure sensor if used to the EGR vacuum port at thecarburetor.When vacuum overcomes the diaphragm spring pressure, a pintle within the valve is lifted off its seat andexhaust gas, which reaches the EGR valve through special passages, is metered into the intake manifold.PINTLESdifferent diaphragm spring loads and flow control orifices. The unit combines the functions of the EGR valveand back-pressure transducer into a single component.A restrictor plate is not required.Refer to figure 4A-11. The flow recirculation of exhaust gas is controlled by a movable pintle. In the relaxed position, spring pressure holds the pintle againstits seat, confining exhaust gases to the exhaust manifold. Carburetor vacuum is available at the power diaphragm to pull the pintle from its seat. This cannothappen while the vacuum bleed valve in the power diaphragm is open.BLEEDVALVEVACUUMAJ4201 2Fig. 4A-9 EGR Valve PintlesFROM CARBURETORPORTED VACUUMSOURCEDIAPHRAGMSPRINGCDIAPHRAGM.70421Fig. 4A-1 1 EGR Valve with integral Back-Pressure SensorPINTLESEATTO INTAKEPORTCONTROLFLOW AREAU0FROM EXHAUSTPORTA42013Fig. 4A-10 EGR Vaive without Back-Pressure SensorEGR Valve with Integral Back-Pressure SensorCalibration is accomplished by the selective use ofExhaust gas exerts pressure back-pressure insidethe exhaust manifold whenever the engine is running.This pressure is conducted through the hollow pintlestem into the control diaphragm chamber. If this pressure is great enough to overcome control spring pressure, the control diaphragm is moved against the bleedvalve. Full vacuum is now applied to the power diaphragm and the pintle moves. EGR now begins. If backpressure drops sufficiently, the control diaphragmmoves away from the bleed valve. The power diaphragmagain relaxes and EGR stops.System pressure remains constant, within the rangeof the unit. Recirculation is a function of the exhaustmanifold back-pressure level. EGR is dependent onback-pressure and is a fixed percentage of the incomingcharge.
V.EMISSIONS CONTROLS-EXHAUST SYSTEMS 4A-13EGR Valve Test.toi the engine and exhaust system .found on that vehicle.Always replace the same restrictor plate originallyValve Opening Testiiis tailed.With engine at operating temperature and curb idle,rapidly open and close throttle. Throttle should beopened sufficiently for engine to reach 1500 rpm. Adefinite movement should he noticed in he EGRdiaphragm.If the diaphragm does not move, the probable causesare: faulty vacuum signal to EGR, defective E;R diaphragm or defective hack-pressure sensor diaphragm, ifequipped. Check vacuum lines for leaks.Valve Closing TestWith the engine at operating temperature and curbidle, manually depress the EGR valve diaphragm. Thisshould cause an immediate engine speed d:rop, indicating that the EGR valve had been properly cuttingoff the flow of exhaust gas at idle.If there is no change in engine rpm and the engine isidling properly, exhaust gases do not reach the combustion chamber. The probable difficulty is a pluggedpassage between the EGR valve and the intakemanifold.If the engine idles poorly and rpm is not greatly affected by compressing the EGR diaphragm, the EGRvalve is not closing off the flow of exhaust gases. Thereis a fault in the hoses, hose routings or the valve itself.EGR Valve ReplacementRemoval1 On V-8 engines, remove air cleaner assembly.2 Disconnect vacuum hoses.3 Remove two retaining bolts from manifold.4 Remove EGR valve, gasket, spacer and attachedexhaust back-pressure sensor assembly if used, restrictor plate and its gaskets if used.5 Clean EGR pintle if required refer to EGRValve Maintenance.6 Discard used gaskets and clean all matingsurfaces.Installation1 Install restrictor plate if used between twogaskets and install spacer if used, EGR gasket, andEGR valve.2 Install retaining bolts and tighten to 13 footpounds torque.3 Connect vacuum lines and install air cleanerassembly if removed.NOTE: The non-integral exhaust back-pressure assembig, /f. used, should extend toward the left side on V-8engines. The stainless steel rest rictor plate is calibratedEGR Valve Maintenance-Cherokoe-Wagoneer-TruckRemove all lead or carbon deposits from the stainlesssteel metering pintle of the valve using a wire brush.After cleaning, depress the diaphragm, cap the vacuuminlet, and repeatedly open the EGR valve manually bypressing down on the diaphragm and releasing: Pintleshould[ remain retracted; if it does not, diaphragm has aleak and valve must be replaced.On six-cylinder engines, lead or carbon deposits willbuild most rapidly in the exhaust gas discharge passageupper hole. If the deposits cannot be removed with aspiral-type wire brush, a 9/16-inch drill may be used.Coat the tip of the drill with heavy grease and use pliersVise-Grip to rotate the bit in the discharge passage.EGR CTO SWITCHThe EGR CTO switch is located at the coolant passageof the intake manifold adjacent
Emission control systems are required to meet exist ing standards for exhaust, crankcase, and raw fuel va por emissions. The systems control emission of hydrocarbons, carbon monoxide, and oxides of nitrogen at the levels specified by Federal or Ca]ifornia standards. Federal Emission Standards and the standards which apply in California differ .
650 47 No.2 front exhaust pipe (Front TWC) x Exhaust manifold 62 630 46 Pipe support bracket x Transmission 43 440 32 No.2 front exhaust pipe (Front TWC) x Front exhaust pipe (Rear TWC) 43 440 32 Front exhaust pipe (Rear TWC) x Center exhaust pipe 43 440 32 Sub heated oxygen sensor (California only) x Front exhaust pipe 20 200 14 EG–174
227 521-12730 5th Section Vacuum Roll Exhaust Fan 6675 / 7183 228 521-12360 Hood Exhaust Fan #3 6676 / 7184 231 200Dryer8 521-12365 Main Hood Exhaust #4 6677 / 7185 232 521-12369 After Hood Exhaust Fan #6 6678 / 7186 233 521-12367 Main Hood Exhaust Fan #5 6679 / 7187 248 200Vacuum Trench Vacuum Trench Exhaust 6687 / 7188 249 200Pulper
SUPPLY CORPORATION 398 BUYER'S GUIDE ASCOT SUPPLY CORPORATION AUTO & FLEET SERVICE // EXHAUST HOSES, EXHAUST EXTRACTION Exhaust Hoses & Tailpipe Adapters AUTO & FLEET SERVICE // EXHAUST HOSES, EXHAUST EXTRACTION 6 Exhaust Hoses, Tailpipe Adapters ASCOT NO. MFG. NO. DESCRIPTION 391-00125 DF25 2-1/2" Rubber Door Port 391-00130 ADF30 3" Aluminum .
that meet the CARB's 2004 exhaust emission standards. Engines meeting these standards have 20% lower emissions than One Star - Low Emission engines. The three-star label identifies engines that meet the CARB's 2008 exhaust emission standards. Engines meeting these standards have 65% lower emissions than One Star - Low Emission engines.
emission characteristics of marine diesel engines. Keywords: marine diesel engine; exhaust emissions; fuel-based emission factor; energy-based emission factor; specific emission 1. Introduction Seaborne trade can bring huge economic benefits to the world, accounting for more than 80% of global trade, and it is still growing [1,2].
The Tri-Stack system is your solution for exhaust fume and odor control Time tested superior design: The proven product for your building exhaust Strobic Air's Tri-Stack exhaust systems are practical, cost-effective, and energy efficient solutions for all of your exhaust needs. Whether your concern is pollution abate-
Ecotoxicological characterization factor [PDF·m3·day/kg]: Emission to urban air Emission to cont. rural air Emission to cont. freshwater Average 1,8E 02 1,8E 02 4,5E 02 Worth Case 4,6E 02 4,6E 02 1,2E 03 Emission to urban air Emission to cont. rural air Emission to cont. freshwater cancer non-canc. total cancer non-canc. total cancer non-canc .
inertia of pile cross section with respect to the neutral axis. Relationships between variables lem p M dM V dV V M dx x x x x x F y p y I M x dx p right p (soil resistance) p left a) Pile loading b) Net soil reactionc) Pile deflection d) Slope e) Bending moment. The Genesis of the P-Y Curve: (Reese and Van Impe, 2001) B . P-y curve Method . P-Y CURVES . p-y model used for analysis of .
