Mazda Training manual — part 13

Powertrain Engines

Service Procedures

Adjusting the Idle Speed

•

On the Mazda3 with ZJ and Z6 engine the idle speed must be adjusted at specified
service intervals using M-MDS. To perform the procedure select the PIDs RPM (Rpm)
and test# (Mode) in the M-MDS Datalogger, and set the PID test# to ON. Now the PCM
(Powertrain Control Module) uses a fixed value for the ignition timing control, so that the
idle speed can be adjusted on the air adjusting screw of the throttle body.

NOTE: The throttle body is equipped with a stop screw, which is used by the manufacturer

to adjust the fully closed throttle position. Any adjustment of the stop screw is
prohibited and can cause malfunctions such as sticking of the throttle valve.

L1001.4_01152

1

Air adjusting screw

3

Throttle body

2 Throttle

valve

Curriculum Training

01-39

Engines Powertrain

MZI-type Engines

•

In the MZI engine line-up the following engines are available:

–

1.25 MZI engine with 1.25 L displacement

–

1.4 MZI engine with 1.4 L displacement

–

1.6 MZI engine with 1.6 L displacement

•

The MZI-type engines are fitted in the Mazda2 (DY) models. They are equipped with a
multipoint manifold injection system and a distributorless ignition system (ignition coil
unit).

Mechanical

Features

•

The mechanical system of the MZI-type engines has the following features:

–

Belt driven 16 valve DOHC engine

–

Valve train with manual or automatic timing belt tensioner, and mechanical bucket
tappets

–

No variable valve timing system

–

V-ribbed belt drive with elastic belts

01-40 Curriculum

Training

Powertrain Engines

Overview

L1001.4_01040

NOTE: Some of the components of the MZI-type engine are very similar in construction and

operation to those of the L-type engines. Therefore, this section only describes the
components which are new or differ from those of the L-type engines.

Curriculum Training

01-41

Engines Powertrain

Cylinder Block

•

The cylinder block features a bearing support frame, in which the main bearing caps are
integrated. The bearing support frame is matched to the cylinder block and is not located
by means of guide sleeves, i.e. the components of the crank train (crankshaft,
connecting rod and piston) cannot be replaced separately. If one of the components
exceeds the specification, the cylinder block must be replaced as a complete unit.

•

For this reason, a remanufactured cylinder block is available for the MZI-type engines,
which is delivered completely with crankshaft, connecting rods, pistons, all oil passage
blanking plugs and water drain plugs.

NOTE: Thread repairs on the cylinder block using thread inserts are not permitted.

L1001.4_01041

1 Cylinder

block

3 Crankshaft

2

Main bearing shells

4

Bearing support frame

01-42 Curriculum

Training