Jeep Grand Cherokee

1993-1999 of release

Repair and operation of the car



Jeep Grand Cherokee
+ Cars of the Jeep Grand Cherokee brand
+ Settings and routine maintenance
+ Line six-cylinder engine
+ V8 engine
+ Procedures of the general and capital repairs of the engine
+ Cooling systems, heating and air conditioning
- Power supply system and production of the fulfilled gases
   General information
   Procedure of dumping of pressure of fuel
   Check of pressure of fuel and functioning of the fuel pump
   Removal and installation of the fuel tank
   Cleaning and repair of the fuel tank - the general information
   Repair and replacement of fuel lines
   Removal and installation of the fuel pump
   Check of serviceability and replacement of the block of the fuel level sensor
   Removal and installation of assembly of the air cleaner
   Replacement of a cable of gas
   System of injection of fuel - the general information
   Check of serviceability of system of injection of fuel
   Serviceability check, removal and installation of the case of a throttle
   Check of serviceability and replacement of the regulator of pressure of fuel
   Serviceability check, removal and installation of injectors of fuel
   Check of functioning and replacement of components of system of stabilization of turns of idling (IAC)
   Service of system of production of the fulfilled gases - the general information
+ System of electric equipment of the engine
+ Systems of decrease in toxicity of the fulfilled gases and engine management
+ Manual box of gear shifting
+ Automatic transmission
+ Transfer case
+ Coupling and transmission line
+ Brake system
+ Suspension bracket and steering
+ Body
+ System of onboard electric equipment
+ Governing bodies and methods of operation



Check of pressure of fuel and functioning of the fuel pump

See the prevention at the beginning of the Section Procedure of Dumping of Pressure of Fuel (the description of the procedure of dumping of pressure of fuel see in the same place).


Models of 1995 of the issue are not equipped usual vacuum type with the fuel pressure regulator. Here the regulator is built in in the fuel pump. In case of the problems connected with pressure of fuel replace entirely assembly of the fuel pump / block of the sensor.

Primary check

If there are suspicions on deterioration in supply of fuel, first of all check fuel lines for existence of signs of leaks.

Check of functioning of the fuel pump

On all models the fuel pump is located in the fuel tank (see the Section Removal and installation of the fuel pump).


 PERFORMANCE ORDER

  1. Cock the parking brake and ask the assistant to turn the ignition key in position of ON. Listen to the sounds made by the pump in the fuel tank at this time. It has to be the hum lasting about 2 seconds.
  2. Start the engine. Now hum has to become continuous (though will be to catch it because of the working engine more difficultly). If there are no sounds, either the pump, or its relay, or the relay of a contour of automatic shutdown of supply of fuel (ASD) is faulty (you pass to item 1).

Check of pressure

 PERFORMANCE ORDER

  1. Dump pressure of fuel (Section Procedure of Dumping of Pressure of Fuel).
  2. Uncover the union of check of pressure of the fuel located on the fuel highway and connect the manometer to the union.
  1. Connect the manometer to the fuel highway and consider its indications at the engine working at single turns (the model with the 5.2 l engine is shown).
Conducting check of pressure of fuel on the models equipped with the 4.0 l engine.
  1. Start the engine and consider indications of the manometer, having compared them to data of Specifications. Now disconnect a vacuum hose from the fuel pressure regulator. Again at the engine working at single turns take of instrument reading - it has to meet relevant requirements again. Connect a hose into place.

Models of 1995 of the issue are equipped with the fuel pressure regulator which is built in in the block of the fuel pump / sensor of level, there is a possibility of check only of the adjusted fuel pressure.


Models of 1995 of the issue are equipped with the fuel pressure regulator which is built in in the fuel pump.

  1. If results of measurement of pressure of fuel do not meet requirements of Specifications, act as follows:
    • If the result of measurements meets the requirements of Specifications at the vacuum hose connected to pressure regulator, however goes beyond admissible limits at the disconnected hose, check existence of depression in a hose. If depression is present, replace the regulator (Section Check of Serviceability and Replacement of the Regulator of Pressure of Fuel). If depression is not fixed, check a hose for existence of breaks and obstruction.
    • If pressure exceeds admissible value check passability of a hose (or fuel return tubes). If passability is not broken, replace the regulator of pressure (Section Check of Serviceability and Replacement of the Regulator of Pressure of Fuel).
    • If the measured pressure is lower than an admissible limit, do the following:
    • Make sure that the fuel filter is not hammered.
    • Whether check it is overwound and whether the fuel hose between a gasoline tank and the fuel highway is blocked.
    • Check serviceability of functioning of the regulator of pressure of fuel.
    • Check fuel lines for existence of signs of leaks.
  2. If any of refusals of the listed above components are not found, check serviceability of a condition of the fuel pump.

Fuel pressure regulator components

 PERFORMANCE ORDER

  1. Connect the vacuum pump to the fuel pressure regulator. Consider indications of the manometer without creating depression on the regulator and at depression. About increase in depth of depression pressure of fuel has to fall. Compare results of measurements to data of Specifications.

Models of 1995 of the issue are equipped with the fuel pressure regulator which is built in in the block of the fuel pump / sensor of level (see an illustration). Thus, there is a possibility of check only of the adjusted pressure.


  1. Connect the vacuum pump to the regulator of pressure of fuel and measure fuel pressure at first without creating depression.

... and then having created it - in the presence of depression pressure has to fall.

  1. Connect a vacuum hose to the regulator and check fuel pressure at the engine working on idling, compare results of measurements to requirements of Specifications. Disconnect a hose and repeat check - pressure has to jump up to the maximum admissible value right after a hose detachment. If pressure on single turns is too high (at the disconnected hose), connect the vacuum gage to a hose and measure depression depth in it.
  2. If pressure of fuel is too LOW, press the line of return of fuel and track change of indications of the manometer. If pressure did not increase, then or the fuel pump is faulty, or passability of the line of supply of fuel is broken. If pressure jumped up, replace the regulator of pressure of fuel (Section Check of Serviceability and Replacement of the Regulator of Pressure of Fuel).

It will be required to make special rubber inserts between the fuel highway and the returnable line as steel metal lines cannot be pressed for the purpose of performance of this check.

  1. If the indication of the manometer is too high, disconnect the line of return of fuel and try to blow it for passability check. If passability of the line is not broken, replace the regulator of pressure of fuel (Section Check of Serviceability and Replacement of the Regulator of Pressure of Fuel).

Check of a condition of the fuel pump

 PERFORMANCE ORDER

  1. In case of problems with functioning of the fuel pump first of all check the fact of its inclusion (see item 1).
  2. If the pump does not turn on, (sounds are absent), pass to performing procedures of the following item.
  3. Disunite the electric socket of the fuel pump and directly connect to its plugs battery tension (see an illustration below). The pump has to turn on.
  1. By means of wires from a set for start of the car from an auxiliary source connect the positive plug of the battery to the plug of an orange-black wire of the socket of the pump, and the negative plug - to the plug of a black wire of the socket and listen to the sounds speaking about turning on of the pump (the model with the 5.2 l engine is shown).
  1. Make sure available battery tension on plugs of the feeding half of the socket of the pump at the included ignition (a key of position of ON). If tension is present, replace the pump (The section Cleaning and repair of the fuel tank - the general information). If there is no tension, check a condition of the main relays.

Check of the main relays

For full check of the fuel pump have to be checked as the relay of automatic shutdown of supply of fuel (ASD), and the pump relay. Checks of both relays are made according to the similar scheme.

The scheme of an electric chain of system of injection of fuel of models of 1995 of the issue equipped with the 5.2 l engine (the scheme of other models is similar)


 PERFORMANCE ORDER

  1. For check of the relay, take it from the nest in a motive compartment.
  1. Find the ASD relay (shooter) and the relay of the fuel pump in a motive compartment.
  1. Take the relay from the nest and make sure available battery tension on nest plugs at the included ignition.
  1. Check presence of supply voltage on ASD relay nest plugs.
  1. If tension is absent, check a pump safety lock. If tension is absent also on a safety lock, check a condition of an electric contour of the pump.
  2. Connect the positive probe of an ohmmeter to the plug 86, and negative - to the plug 85 and measure resistance. It has to equal about 75 Ohms.
  1. Measure resistance between plugs 86 and 85; it has to equal about 75 Ohms.
  1. Connect the positive probe of an ohmmeter to the plug 30, and negative - to the plug 87A and again measure resistance. The ohmmeter has to show conductivity (zero resistance).
  1. Also measure resistance between plugs 30 and 87A; conductivity has to take place.
  1. Connect the positive probe of an ohmmeter to the plug 30, and negative - the plug 87. Conductivity has to be absent.
  2. Give battery tension on the plug 86 and ground the plug 85. Check whether conductivity between plugs 87 and 30 takes at the same time place. If is not present, replace the relay.