Jeep Grand Cherokee

1993-1999 of release

Repair and car operation



Jeep Grand Cherokee
+ Cars of mark Jeep Grand Cherokee
+ Options and routine maintenance
+ Рядный the six-cylinder engine
+ Engine V8
+ Procedure of the general and engine major repairs
+ Systems of cooling, heating and air conditioning
+ The power supply system and release of the fulfilled gases
+ System of an electric equipment of the engine
- Systems of decrease in toxicity of the fulfilled gases and engine management
   The general information
   System of multiitem injection of fuel (MPFI) and information gauges - the description
   Removal and installation of the electronic module of management (РСМ)
   The description of a principle of action of system of self-diagnostics and procedure of reading of codes of malfunctions
   Information gauges
   System of operated ventilation картера (PCV)
   System recycling the fulfilled gases (EGR)
   System of catching of steams of fuel (EVAP)
   The Katalitichesky converter
+ Manual box of a gear change
+ Automatic transmission
+ Distributing box
+ Coupling and трансмиссионная a line
+ Brake system
+ Suspension bracket and steering
+ Body
+ System of an onboard electric equipment
+ Controls and operation receptions




System of multiitem injection of fuel (MPFI) and information gauges - the description

The system of multiitem injection of fuel (MPFI) provides giving in the engine of demanded quality of a mix at any service conditions of the car. System injectors provide fuel injection in each of inlet ports.

Brain of system of injection is the module of management РСМ. РСМ it is located in a forward corner of an impellent compartment.

РСМ receives and processes peak (on pressure) signals from set of various gauges, switches and the relay. All entering signals will be transformed to the figures which are read out by the module of management, carrying out on the basis of their analysis constant thin fine tuning of such major parametres of the engine, as a corner of an advancing of ignition, duration of inclusion of a current of the coil of ignition, duration of an impulse of inclusion of an injector and turns of idling of the engine for the purpose of minimisation of pollution of atmosphere by products of combustion and reception of the maximum return from the engine. Besides, РСМ supervises work of the fan of system of cooling, зарядного a current of the generator and such components of system of decrease in toxicity of the fulfilled gases, as electromagnets EGR and purges of a coal adsorber of system EVAP. РСМ it is capable to change also the program according to working conditions.

Components of systems of decrease in toxicity of the fulfilled gases and engine management of models 4.0 of l (for models 5.2 of l the scheme is similar)

1 — Д/В - the Gauge-switch
2 — VSS - the Gauge of speed of the car
3 — Э/М - the Electromagnet

4 — ASD Automatic switching-off of giving of fuel
5 — О/D - Raising transfer

РСМ carries out the constant control of set of own entrance and target contours. In case of malfunction occurrence in system MPFI the information on it is fixed in memory of the module. To make diagnostics of malfunctions of components of system MPFI without presence of special expensive factory manufacturing of the tool and the input reader of codes of malfunctions DRB II (№ С-4805) or its equivalent it is not obviously possible, however in many cases it is possible to try to localise a source of suspected refusal, having limited a search circle at least to a concrete contour. The given work always begins with reading of codes of malfunctions, then visual survey of components of system for the purpose of check of a condition and reliability of fastening of conducting and electric sockets is made. More often easing of fastening or a detachment клеммных connections of electroconducting or vacuum lines appears a cause of a failure. Instructions on a conclusion of the diagnostic information from memory РСМ on a control lamp «Check up the engine» the Description of a principle of action of system of self-diagnostics and procedure of reading of codes of malfunctions are resulted in Section.

Information gauges

Into number of set of the sources which are handing over the information on РСМ enter:

  • The relay муфты couplings of the conditioner of air
  • The relay of automatic switching-off of giving of fuel (ASD)
  • The gauge-switch of stoplights
  • The gauge of position of a camshaft
  • The gauge of temperature of air
  • The gauge of temperature of a cooler
  • The gauge of position of a cranked shaft
  • The gauge of absolute pressure in the pipeline (МАР)
  • The oxygen gauge
  • The gauge of position throttle заслонки (TPS)
  • The gauge-switch of the permission of start (transmission position)
  • The gauge of speed of the car (VSS)

The relay муфты couplings of the conditioner of air (К/В)

Relay work муфты couplings К/В operates РСМ. Management is carried out at the expense of inclusion-deenergizing of a contour of grounding of the relay. When РСМ receives inquiry from control panel K/V (a control system of a climate), it gives a command on inclusion of the motor of system of stabilisation of turns of idling (IAC) for the purpose of corresponding updating of turns. The relay of management is located by coupling К/В in power supplies centre value of distribution near to the battery.

Site of centre value of distribution of power supplies.

The relay of automatic switching-off of giving of fuel (ASD)

If absence of a signal of ignition (distributor) or from gauges of position of a distributive or cranked shaft takes place at ignition key turn in position RUN (Movement), relay ASD disconnects a food of the electric fuel pump, injectors of fuel, the coil of ignition and the warmed up oxygen gauge. The disconnecting relay is located in power supplies centre value of distribution near to the battery.

The gauge of position of a camshaft

The gauge of position of a camshaft includes the semiconductor working on effect of the Hall, and gives out a signal used for synchronisation of work of power supply systems and ignition. The synchronising signal is developed by the semiconductor at rotation of a ring of the gauge with the screen, located in the distributor.

The gauge of position of a camshaft of the engine of 4.0 l.

The gauge of temperature of air

The gauge of temperature of air, established in the inlet pipeline defines temperature of entering air and hands over the corresponding information on РСМ. The information is used by the module at updating of an air-fuel mix.

Site of the gauge of temperature of air on the engine of 4.0 l.

Site of the gauge of temperature of air on the engine of 5.2 l.

The gauge of temperature of a cooler

The gauge of temperature of the cooler, screwed in in the thermostat case, traces cooler temperature, sending corresponding signals on РСМ. This data together with the information received from the gauge of temperature of air is used by the module at updating of quality of a gas mixture and turns of idling in the course of an engine warming up. The gauge also serves for fan inclusion blowing a radiator.

Site of the gauge of temperature of a cooler of the engine of 4.0 l.

Site of the gauge of temperature of a cooler of the engine of 5.2 l.

The gauge of position of a cranked shaft

The gauge of position of a cranked shaft fastens on a transmission dome. The gauge transfers on РСМ the information on current position of a cranked shaft. As initial given the gauge uses cuts on приводном a disk of the converter of rotation or a flywheel.

Site of the gauge of position of a cranked shaft of engines of 4.0 l equipped АТ.

Site of the gauge of position of a cranked shaft of engines of 4.0 l equipped РКПП.

The gauge of absolute pressure in the pipeline (МАР)

Gauge MAR is located on a partition or a wall of an impellent compartment. The gauge defines depth of depression in the inlet pipeline through the vacuum line connected to the case of a throttle. The gauge transfers the read instruments on РСМ together with the data about barometric pressure in the form of pressure varying on amplitude. In a compartment with the information obtained from other gauges this data allow the management module to define demanded structure of a gas mixture.

Gauge MAR site on the engine of 4.0 l.

Gauge MAR site on the engine of 5.2 l.

Various gauges-switches

Gauges-switches (such as the switch of the permission of start, the conditioner of air, the control of speed and stoplights) supply РСМ with the information allowing it to make adjustment of functioning of the engine depending on a condition of the various equipment (incl. / off). Indications of the given gauges-switches (high/low level of a signal) are difficult for defining without diagnostic measuring instrument DRB II.

The oxygen gauge

The oxygen gauge located in a reception pipe of system of release of fulfilled gases (right on engines V8), gives out peak (on pressure) a signal depending on presence at system of release of the fulfilled gases of oxygen. For acceleration of an exit of the gauge in operating conditions at warming up of the engine the gauge is equipped by the built in electric heater. If in the fulfilled gases the considerable percent of oxygen (a poor mix) contains, the gauge signal has smaller amplitude; at the small maintenance of oxygen (a rich mix) the amplitude of pressure given out by the gauge raises. Tracing maintenance percent in the fulfilled gases of oxygen and translating it in an electric signal, the gauge works as the gauge-switch of pauperisation-enrichment of a gas mixture. The signal from the gauge arrives on РСМ which on the basis of its analysis increases or reduces width of an impulse (duration) of inclusion of injectors of fuel.

Site of the oxygen gauge.

The gauge of position throttle заслонки (TPS)

Located in the case of throttle TPS defines a corner of a deviation throttle заслонки. Pressure developed by the gauge increases or decreases depending on width of opening заслонки. Arriving on РСМ the given signal in a compartment with the data received from other gauges, allows the module processor to carry out updating of quality of a mix depending on operating conditions of the engine, such as an acceleration/deseleratsija, work on single turns or at completely open throttle заслонке.

Site TPS (the engine 5.2).

The gauge of distance (speed) of the car (VSS)

VSS, located on lengthening картера to transmission or a distributing box (depending on car equipment), serves for definition of speed of movement of the car. The gauge develops eight impulses for each turn of a power shaft and transfers them on РСМ. The given signals are compared by the module to a signal of the closed position throttle заслонки from TPS allow to distinguish closing conditions заслонки at dump of turns of the engine and at work of the last on single turns (on the at a stop car) At сбрасывании engine RSM turns carries out the control over motor IAC functioning, achieving a demanded signal from МАР; at engine work on single turns РСМ operates motor IAC, supporting desirable frequency of rotation of the engine.

Site VSS.