Isuzu N-Series. Manual - part 414

6D6-2 QOS II PREHEATING SYSTEM

GENERAL DESCRIPTION

QOS II preheating system features a quick-on glow plug with thermometer control of the glowing time and the after-
glow time function.
The system consists of a timer, indicator lamp, thermosensor, relay and temperature self-control type glow plug (4
pcs).
With the employment of the thermosensor, the glow time changes according to the engine coolant temperature, thus
allowing optimum starting conditions to be obtained.
The afterglow time function is controlled by thermosensor.

QOS II PREHEATING SYSTEM 6D6-3

Component

Quick-On-Start II (QOS II)

N6A1664E

6D6-4 QOS II PREHEATING SYSTEM

STARTING CIRCUIT DIAGRAM (REFERENCE)

Component

N6A1092E

QOS II PREHEATING SYSTEM 6D6-5

Inspection and Repair

Make the necessary adjustments, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.

Quick-On-Start II (QOS II)

System

1. Disconnect the connector of the thermo switch.

2. Set the voltage meter in connection as shown in

the illustration.

3. Turn the key switch to “ON” position without engine

turned and check the following items.

When abnormal, check the QOS timer, the glow re-
lay and the thermo switch.
When normal, check the glow plug.

Timer

1. Disconnect the connector of the thermo switch.
2. Set the voltage meter in connection as shown the

illustration with connector connected.

3. Turn the key switch to “ON” position without engine

turned, and check the following.

Glow Plug Relay

Location

Specification
Measure the glow relay resistance between the terminal
(4) and the (5) with a circuit tester.

Glow Indicator Lighting Time

Seconds

Standard

3.5

Power Source Voltage Indi-
cating Time

Seconds

Standard

18

N6A1093E

N6A1094E

0 Volts Indicating Time

Seconds

Standard

18

N6A1095E

N6A1096E