IA 14 EMISSIIIN C0llTIl0LS EXllAUST SYSTEMS VI vacuum inlet and repeatedly open the EGR valve 3 Using 7 8 inch open end wrench remove manually by pressing down on the diaphragm and switch from block releasing Pintle should remain retracted if it does not diaphragm has a leak and valve must be replaced On six cylinder engines lead or carbon deposits will n m n sIx cyI m r build most rapidly in the exhaust gas discharge pas l Instal EGR CTO switchin block sage upper hole If the deposits cannot be removed 2 Couuwt Vscuumliues with a spiral type wire brush a 9 16 inch drill may be 3 Install coolant and Purge air fl Wm 0ll E Y used Coat the tip of the drill with heavy grease and tern use pliers to rotate the bit in the discharge passage llnmoval V 8 Engina Gl 11 Swllglg 1 Drain coolant from radiator 2 Remove air cleaner assembly The EGR CTO switch is located at the coolant pas 3 Rvmvvfi wil bracket attaching S F W and UD sage of the intake manifold adjacent to the oil filler coil away from EGR CTO switch tube on V 8 engines and at the left side of the cylin 4 DlS 0 Vacuum hoses l 1 0m CTO switch E L l b iZZi 2 E i JE 1 i2 ZZ 3i2 i T Wujyost orc or erg g cweyrg the outer port E connects to the exhaust back mt Mme efmle Temmng SWL C fmm m a G pressure sensor when the vehicle is so equipped or to m if ld the EGR valve 5 Using 7 8 inch open end wrench remove When coolant temperature is below the rating of switch from intake manifold the CTO switch there is no vacuum signal to the EGR system The EGR CTO switch on the Jeep CJ models opens at 1l5 F and has a black body or a black paint Insmmmn v 8 Engl dah All other Jeep medele have an woop CTO Switch 1 Install EGR CTO switch in intake manifold with a yellow body or yellow paint dab 2 Install Boil and bracket with attaching screw 3 Connect vacuum hose to switch 4 Install air cleaner assembly gn fm 5 Install coolant and purge cooling system of air Engine coolant temperature must be below EXMUST cK PnEsSunE susan 1 Check vacuum lines for leaks and correct rout Exhaust back pressure sensors are used on all Jeep ings fig 4A 8 and 4A 9 CJ models and on all vehicles sold in California This 2 Disconnect vacuum line at back pressure device monitors exhaust back pressure and permits 5 0l lf Bqulplied DY at l l EGR V8lV and 0l l l1 EGR operation only when engine operating conditions linetoavacuum gauge are favorable for EGR action with a given en 3 Operate engine at 1500 rpm no vacuum should gine exhaust combination Back pressure sensors are be indicated on gauge If vacuum is indicated replace variously calibrated are not serviceable and must be EGR CTO switch replaced when necessary with the same part number 4 Idle engine until coolant temperature exceeds The exhaust back pressure sensor consists of a 115 F black color code or 160 F yellow color code diaphragm valve and a spacer connected by a metal The temperature gauge needle is about halfway be tube which projects into an exhaust port in the spacer tween the cold mark and the beginning of the band at body fig 4A 12 The EGR valve mounts directly on 115 F and about at the beginning of the band at the spacer 160 F The metal tube connecting the diaphragm valve to 5 Accelerate engine to 1500 rpm carburetor the spacer picks up exhaust back pressure from the P0 d Vuuuum should be indicated 0 V uu l S u8 exhaust port into which it pro3ects When the back lf not replace EGR CTO switch pressure reaches the calibrated level of the sensor the diaphragm valve spring pressure is overcome permitt ing a vacuum signal to the EGR valve when the wo SIX cyllldar coolant temperature override CTO switch is open 1 Drew l8n from d refer to EGR CTO Switch section 2 Dl V mlln S This system permits EGR operation only when the WARNING Serious burns can result if not coolant is engine has warmed up sufficiently and when exhaust not drained before removing switchfriom block pressure is relatively high as in acceleration and at