Nissan Patrol, Ford Maverick

1988-1997 of release

Repair and operation of the car

Nissan Patrol and Ford Maverik
+ Cars of the Nissan Patrol and Ford Maverick series
+ Diagnostics of malfunctions
+ Settings and routine maintenance
+ Engine
+ Cooling systems, heating and air conditioning
+ Power supply system and production of the fulfilled gases
- Systems of decrease in toxicity of the fulfilled gases
   System of ventilation of a case
   System of recirculation of the fulfilled gases (EGR) - models of 3.0 l
   Control system of quality of mix during a deseleration
   Control system of temperature of the soaked-up air
   System of catching of fuel evaporations (ECS)
+ Systems of electric equipment of the engine
+ Transmission
+ Coupling
+ Brake system
+ Forward and back bridges, running gear and steering
+ Body
+ Onboard electric equipment

Control system of quality of mix during a deseleration

Implementation of the diagnostic procedures described below requires the manual vacuum pump with the vacuum gage.

Principle of action

Deep depression in the inlet pipeline when dropping turns of the engine (deseleration) leads to emission in the atmosphere not burned down in combustible gases and oil, to increase in issue of hydrocarbonic connections. For the purpose of decrease in level of issue of hydrocarbonic connections the carburetor is equipped with the device of impoverishment of mix at a deseleration (BCDD) (see an accompanying illustration).

On reaching depression depth in the inlet pipeline of a certain value the valve of management of BCDD opens perepuskny the air channel therefore the volume of the fuel injected into the carburetor through a cast jet is reduced. At the same time completeness of combustion of mix increases that leads to reduction of issue of hydrocarbonic connections.

In order to avoid an engine detonation after a final stop, model with RKPP are equipped with the electromagnetic BCDD valve which blocks operation of the valve of management of BCDD.

Valve check of management of BCDD

In usual conditions the valve of management of BCDD does not need checks and adjustments, however if need for adjustment nevertheless arises, act as it is described below.


  1. On models with RKPP disunite the electric socket of the carburetor.

Rassoyedineniye of the socket of the carburetor cuts off power electromagnetic BCDD valves and interruptions in supply of fuel (locking), preventing their operation in view of what during performance of this check the engine can not hold single turns.

  1. Completely weaken a damper of bystry idling (if that is provided).
  2. Remove the top cover of the air cleaner and connect the vacuum gage to the inlet pipeline.
  3. Lift engine turns to value 3 000 ÷ 4 000 in a minute, then release the accelerator pedal. At an otpuskaniye of gas the frequency of the sound made by a carburetor mouth has to change. Such change of frequency indicates operation of the valve of management of BCDD.
  4. Repeat verification of the last paragraph, watching indications of the vacuum gage during change of frequency of sounding. On models of 4.2 l the device has to register depth of depression 570 ± 50 mm of mercury., on models of 3.0 l - 580 ± 50 mm of mercury.
  5. If change of frequency of sounding does not happen, or depth of depression exceeds nominal rate, remove a rubber stopper from the valve of management of BCDD and turn the adjusting screw clockwise. If frequency still does not change, remove the BCDD valve from the carburetor and make sure of operation of its plunger when giving depression. In case of need replace the BCDD valve.

Do not press the adjusting screw!

  1. If change of frequency happens with a depression depth below nominal, remove a stopper and turn the adjusting screw counterclockwise, achieving the required result.
  2. Execute adjustment of a damper of bystry idling.

Check of the electromagnetic valve of management of BCDD


  1. Disunite the electric socket of the carburetor.
  2. Give battery tension on electromagnet plugs in the carburetor socket (see an accompanying illustration).
1 — 4,2 l
2 — 3,0 l
  1. The click of operation of the electromagnetic valve in the carburetor has to sound. Otherwise replace the valve.