Honda Civic - the Repair manual and operation

4.1.7. The VTEC systems - the general information and check of a condition of components

General information

Some of models of the Honda cars are equipped with electronic system of correction of phases of gas distribution (VTEC). On the Civic models the VTEC system of one of two various types (VTEC and VTEC-E) can be used.

Distinction between the ordinary engines and engines equipped with the VTEC system consists in a complete set and the principle of operation of the valvate mechanism. A design of the block of the engine and all hinged knots and units, and also schemes of the organization of lubrication systems and cooling on both units are identical. The engine which is externally equipped with the VTEC system differs in existence from above on a cover of a head of cylinders of a convex inscription of the corresponding content (VTEC).

The onboard processor of the models equipped with the VTEC system is capable to correct phases of operation and the size of opening of inlet valves due to use of various size of cams of the camshaft. The processor, depending on the data arriving from the information sensor, either includes, or switches off system.

As initial parameters for the VTEC systems of both types the following is used:

  a) Frequency of rotation of the engine (rpm);
   b) Speed of the movement of the car (miles/h);
   c) Output signal of the sensor of provision of a butterfly valve (TPS);
   d) The current load of the engine determined by indications of the sensor of absolute pressure in the inlet pipeline (MAR);
   e) Temperature of cooling liquid.

Configuration and the principle of functioning of the VTEC-E systems differ from those for the VTEC systems a little (see below).

VTEC-E (D16Y5)

The camshaft is equipped with both primary, and secondary cams of the drive of inlet valves. Cams differ both in a form, and on height of rises, i.e. the parameters determining duration and extent of opening of valves.

At small turns of the engine secondary valves work from own cams of the camshaft having very small rise and a peaked form (i.e. valves are slightly opened only slightly and very much for a while), holding the sprayed fuel from consolidation in a head of cylinders. At the same time the good torque with high speed of response to gas develops.

If there is a need for increase in return of the engine, secondary yokes are blocked with primary by means of the special hydraulic device with electronic control.

Secondary yokes cease to contact to own cams up to that moment as the system will not be disconnected. At the same time both valves open on full height and with the maximum duration, providing increase in turns and return of the engine.

VTEC (D16Y8)

Cams of the drive of primary and secondary inlet valves of the camshaft in this system are identical in a form and height of rises. Between them the additional third cam called by also intermediate is located. These intermediate cams differ in the bigger height and smaller sharpness of rise that provides the big size and duration of opening of the valve.

At small turns of the engine both primary, and secondary inlet valves work from own cams and open on identical height and with an identical duration (unlike the VTEC-E system). When there is a need for increase in return of the engine, yokes of both inlet valves by means of the special hydraulic device with electronic control are blocked with an intermediate yoke. At the same time duration and height of opening of both valves is defined by a form of the intermediate cam differing in the bigger height and smaller pointedness of rise.

Primary and secondary yokes cease to contact to own cams until the system is not disconnected.

The system allows to try to obtain optimum torque both at small, and at high turns of the engine, depending on the current loading enclosed to it.

Check of a condition of components

Proofreaders of valvate gaps (only VTEC)

Four proofreaders of valvate gaps are placed in holders, forming similarity of hydraulic pushers.

PERFORMANCE ORDER

1. Otboltite also remove assembly of the holder. 2. Take from the holder of assembly of individual proofreaders. 3. Fingers check freedom of movement of each of proofreaders. In case of identification of points of a zakusyvaniye replace defective assemblies.

Plate of distribution of phases, plug and returnable spring (only VTEC-E)

Four plates of distribution of phases with returnable springs (see an illustration below) are put in holders of the camshaft on an axis of inlet yokes.

A) Plate of distribution of phases C) Returnable spring C) Holder of a cam

Apparently from an illustration, the plug of assembly is equipped with a coat hanger for deduction of a spring.

PERFORMANCE ORDER

1. Check reliability of fastening of a spring on the holder of the camshaft and a plate of distribution of phases. 2. Examine components on existence of scratches, chips, traces of an overheat and other damages. 3. Defective parts are subject to replacement. 4. The assembly order is clear from an illustration above.

The synchronizing assemblies

PERFORMANCE ORDER

1. After removal and dismantle of assemblies of yokes (see Removal, check of a state and installation of assembly of yokes), take also components of the synchronizing knots (see accompanying illustrations). Only VTEC-E D16Y5: A) Yoke of primary valve C) Yoke of the secondary valve C) Lock piston D) Lock spring E) The synchronizing piston Only VTEC D16Y8: A) Yoke of primary valve C) Yoke of the secondary valve C) Intermediate yoke D) The synchronizing pistons 2. Check a condition of the blocking spring (only VTEC-E). 3. Examine other components of assembly (a yoke with the synchronizing pistons). In case of identification of signs of wear, attritions, deep scratches, zadir or traces of an overheat, replace defective components. 4. Assembly is made as it should be, the return to a dismantle order. Gather components of assemblies of each of cylinders, fasten them with a rubber bandage, only after it establish on an axis (see Removal, check of a state and installation of assembly of yokes).

Electromagnetic valve of blocking of VTEC

Malfunctions in a contour of the electromagnetic valve of blocking of VTEC lead to operation of a control lamp "Check the engine" for car dashboards. At the same time in memory control units the code of malfunction (DTC) P1259 is brought. On a design the valve of blocking of VTEC with the built-in sensor switch of pressure is similar used in the VTEC system of the Integra models. The description of the procedure of check of serviceability of functioning of assembly is provided in the Part Repair of the engine without extraction from the car - the Integra model of the present Chapter.

Masloraspylitel

See Removal, check of a state and installation of assembly of yokes.

Yoke of primary valve

See Removal, check of a state and installation of assembly of yokes.

Yoke of the secondary valve

See Removal, check of a state and installation of assembly of yokes.

Intermediate yoke (only VTEC)

See Removal, check of a state and installation of assembly of yokes.

Intermediate cam of the camshaft (only VTEC)

See Removal, check of a state and installation of assembly of yokes.