Isuzu KB P190. Manual — part 341

6A-4 ENGINE MECHANICAL (4JK1/4JJ1)

How to read the model (This illustration is 4JK1 engine)

RTW56ALF004701

Legend

1. Engine Model (Stamped)

2. Engine Number (Stamped)

3. Front

Explanation of functions and operations

Electronic engine control

With the control unit, the range from injection to air
intake/exhaust, including fuel injection quantity, injection
timing, intake air restriction, EGR, and idling rpm, is
controlled.

Piston

The piston is aluminum-alloy and a thermal flow piston
with a strut cast, while the combustion chamber is a
round reentrant type.

Cylinder head

The cylinder head is aluminum-alloy and there are 4
valves per cylinder. The angular tightening method of
the cylinder head bolt further increases reliability and
durability.

ENGINE MECHANICAL (4JK1/4JJ1) 6A-5

EGR system

Based upon data, including water temperature, engine
speeds or engine loads, it is controlled via Engine
Control Module (ECM) to purify exhaust by recycling
part of it.

Its main components include an EGR valve, an EGR
cooler and various sensors.

Connecting rod cap bolt

The angular tightening method of the connecting rod
cap bolt further increases reliability and durability.

Fuel rail-type electronic control injection system

The fuel rail-type electronic control injection system is
composed of a fuel supply pump that sets the target
pressure of high-pressure fuel and supply it, a fuel rail
that measures such high-pressure fuel and a fuel
injector that turns it into a fine spray and injects it. Each
is controlled via ECM based upon various signals, while
injection timing or fuel injection quantity is controlled
under every possible driving condition.

Fuel injector

The fuel injector is a 6-hole nozzle that adjusts fuel
injection quantity or injection timing by opening or
closing an electromagnetic valve on the head of the fuel
injector.

ECM corrects the dispersion of fuel injection quantity
between fuel injector according to ID code data in
memory. At the replacement of fuel injector, ID code
data should be stored in ECM.

Fuel filter with sedimenter

It is a fuel filter with sedimenter that gets rid of water by
making use of the difference in specific gravity between
light oil and water, which comes with an indicator that
notifies you that it is filled with water.

Preheating system

The preheating system consists of the ECM, the glow
relay, glow plugs and the glow indicator lamp. The
preheating system is operated when the engine coolant
temperature is low, and makes the engine easy to start.

Lubrication system

It is an oil filter with full-flow bypass, which uses a
water-cool oil cooler and oil jet to cool the piston.

Functional inspection

Inspection/adjustment of valve clearance

1. Inspection of valve clearance

• Remove the fuel injector harness assembly.
• Remove the leak off hose.
• Remove the cylinder head cover.
• Rotate the crankshaft to make the No.1

cylinder meet the compression top dead center

(TDC).

RTW76ASH001301

Legend

1. TDC

6A-6 ENGINE MECHANICAL (4JK1/4JJ1)

• Insert a 0.15 mm (0.006 in) thickness gauge

between the roller of the rocker arm and the

camshaft to tighten up the adjusting screw of

the rocker arm. When the movement of the

thickness gauge becomes tight, fasten the

adjusting screw nut of the rocker arm.

Valve clearance

mm (in)

Intake valve

0.15 (0.006)

Exhaust valve

0.15 (0.006)

Note:
Adjust while cold.

2. Adjustment of valve clearance

• Loosen each adjusting screw of the rocker arm

completely.

RTW56ASH003701

Legend

1. Screwdriver

2. Ring

Spanner

3. Valve Clearance Adjust Nut Wrench

Special tool

Valve clearance adjust nut wrench: 5-8840-2822-0
• Insert a 0.15 mm (0.006 in) thickness gauge

between the roller of the rocker arm and the

camshaft to tighten up the adjusting screw of

the rocker arm. When the movement of the

thickness gauge becomes tight, fasten the

adjusting screw nut of the rocker arm.

LHW71BSH001201

Legend

1. Cam;

Exhaust

2. Cam;

Intake

3. Roller;

Intake

4. Roller;

Exhaust

Tightening torque:

Rocker arm adjustment screw nut

18 N

⋅⋅⋅⋅m (1.8 kg⋅⋅⋅⋅m/ 13 lb ft)

Adjustment table

Cylinder

No.

1 2 3 4

Valve
arrangement

IN

EX

IN EX IN EX

IN

EX

No. 1 cylinder
Compression
TDC

No. 4 cylinder
Compression
TDC

× × × ×

• If the No.1 cylinder is the compression TDC, adjust

a valve clearance with mark given on the table

and if the No. 4 cylinder is the compression TDC,

adjust that with

× mark.

• Install the cylinder head cover.

Refer to "Cylinder Head Cover."

• Install the leak off hose.
• Install the fuel injector harness assembly.

Compression pressure inspection

• Warm up the engine.
• Disconnect the negative battery cable.

ENGINE MECHANICAL (4JK1/4JJ1) 6A-7

• Remove the all glow plugs.

Note:
When the harness connector is removed, ECM judges
that it broke down and DTC is recorded. Upon
completion of measurement, never fail to clear the
memory of the ECM.

(For how to clear the memory of the ECM, refer to
“ENGINE CONTROL SYSTEM” Section)

• Connect the negative battery cable.
• Turn on the starter to emit foreign matter within the

cylinders.

• Install an adapter and a gauge of a compression

gauge of the special tool.

RTW56ASH003801

Compression gauge: 5-8840-2675-0

Gauge adapter: 5-8840-2815-0

• Turn on the starter to inspect compression

pressure.

Compression pressure

MPa(psi)/200rpm

Standard 2.84

− 3.24 (412 − 469)

Limit 1.96

(284)

Differences among

the cylinders

294 kPa (43)

• Measure each cylinder one by one.

Note:
To keep engine speed at 200 rpm or more, use fully
charged batteries.

• Remove a compression gauge of the special tool.
• Disconnect the negative battery cable.
• Install the glow plugs.
• Connect the negative battery cable.

A list of defective phenomena

• Engine does not turn over.
• Engine turns over but does not start.
• Excessive black exhaust smoke.
• Excessive white exhaust smoke.
• Engine

knocking.

• Abnormal engine rotation.
• Abnormal battery charging.
• Turbocharger trouble shooting.