Jeep Engines - Oljeep

242 MOPAR PERFORMANCE PARTSCYL. CYL. CYL. CYL. CYL. CYL.I #6 #5 #4 #3 #2 #1The engine will not operate if the PCM does not receive acrankshaft position sensor input.Camshaft Position SensorThe camshaft position sensor contains a hall effect devicecalled a sync signal generator to generate a fuel sync signal.This sync signal generator detects a rotating pulse ring(shutter) on the oil pump drive shaft. The pulse ring rotates180 degrees through the sync signal generator. Its signal isused in conjunction with the crankshaft position sensor todifferentiate between fuel injection and spark events. It isalso used to synchronize the fuel injectors with theirrespective cylinders.IMOUNTINGBOLTS (4)Figure 4 - 50Figure 4 - 51Automatic Shutdown (ASD) Relay8Ob76118The Automatic Shutdown (ASD) relay is located in thePower Distribution Center (PDC). Refer to label on PDCcover for relay location.As one of its functions, the ASD relay will supply batteryvoltage to the ignition coil(s). The ground circuit to operatethe ASD relay is controlled by the Powertrain ControlModule (PCM). The PCM regulates ASD relay operationby switching its ground circuit on and off.Crankshaft Position SensorEngine speed and crankshaft position are provided throughthe crankshaft position sensor. The sensor is a hall effectdevice combined with an internal magnet. The sensorgenerates pulses that are sent to the Powertrain ControlModule (PCM). The PCM interprets the sensor input todetermine the crankshaft position. The PCM then uses thisposition, along with other inputs, to determine injectorsequence and ignition timing.SPARK PLUGSSpark plugs tend to be taken for granted. Once installed inthe engine, they all look the same. Plugs are sold byekeryone, not just auto parts stores and dealers, andtherefore are readily available. We assume that anythingthat fits, works. We extend this assumption to include that,if it fits and works, then that’s all the plug can do. In a stockengine used for “stock” purposes this may be true. In aperformance engine, it’s a long way from the truth and canlead directly to problems. It’s obvious in a race engine thatif the plug doesn’t do its job, we have trouble. We’llprobably blame the ignition system first and then thecarburetor (if equipped). These can be expensivemisdirections. Before we get into these problem areas, let’sback up and identify our plug.Each plug has a “part number” reference or an I.D. number.The basis of this numbering system is the heat range of theplug. Unfortunately, all manufacturers don’t use the samenumbering system for their various heat ranges. This makesit difficult to understand. However, Chrysler-Plymouth-Dodge- Jeep has used mostly Champion plugs andChampion is our current production source. All of our techbooks base their recommendations on Champion plugs. Allthe other manufacturers compare their heat range toChampion’s. With the common base of heat rangeinformation being Champion’s, we’ll concentrate on thisgroup for our discussion. A typical Champion plug for aDaimlerChrysler-built engine would be an RN12YC. Theheat range is 12, but what do the letters mean? Let’s look atthem one at a time. We’ll concentrate on the letters that areused on DaimlerChrysler applications. There are manymore “specials” which are available from Champion.The first letter “R’ stands for resistor. Most newer plugs are“R’ rated as well as all production plugs. The resistor cutsdown on radio interference. If there is no letter in thisposition, then it’s a standard plug. Today, standard plugs areonly used in racing.-- ..T --I 7