Page 122 of 192

MAIN 12 CAUSES OF OVERHEATING
Engine Step Inspection item Equipment Condition Reference page
OFF 1+Blocked radiator
+Blocked radiator grille
+Blocked bumper+Visual No blocking Ð
2+Coolant mixture+Coolant tester 50 - 50% coolant mixture See ``RECOMMENDED
FLUIDS AND LUBRI-
CANTS'' in MA section.
3+Coolant level+Visual Coolant up to MAX level
in reservoir tank and
radiator ®ller neckSee ``Changing Engine
Coolant'', ``ENGINE
MAINTENANCE'' in MA
section.
4+Radiator cap+Pressure tester 78 - 98 kPa
(0.78 - 0.98 bar, 0.8 - 1.0
kg/cm
2, 11 - 14 psi)See ``System Check''
``ENGINE COOLING
SYSTEM'' in LC section.
ON*
25+Coolant leaks+Visual No leaks See ``System Check''
``ENGINE COOLING
SYSTEM'' in LC section.
ON*
26+Thermostat+Touch the upper and
lower radiator hosesBoth hoses should be hot See ``Thermostat'' and
``Radiator'', ``ENGINE
COOLING SYSTEM'' in
LC section.
ON*
17+Cooling fan+CONSULT Operating See ``TROUBLE DIAG-
NOSIS FOR DTC 28'',
EC-113.
OFF 8+Combustion gas leak+Color checker chemical
tester 4 Gas analyzerNegative Ð
ON*
39+Coolant temperature
gauge+Visual Gauge less than 3/4
when drivingÐ
+Coolant over¯ow to res-
ervoir tank+Visual No over¯ow during driving
and idlingSee ``Changing Engine
Coolant'', ``ENGINE
MAINTENANCE'' in MA
section.
OFF*
410+Coolant return from res-
ervoir tank to radiator+Visual Should be initial level in
reservoir tankSee ``ENGINE MAINTE-
NANCE'' in MA section.
OFF 11+Cylinder head+Straight gauge feeler
gauge0.1mm (0.004 in) Maxi-
mum distortion (warping)See ``Inspection'', ``CYL-
INDER HEAD'' in EM
section.
12+Cylinder block and pis-
tons+Visual No scuffing on cylinder
walls or pistonSee ``Inspection'', ``CYL-
INDER BLOCK'' in EM
section.
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to ``OVERHEATING CAUSE ANALYSIS'' in LC section.
TROUBLE DIAGNOSIS FOR ``OVER HEAT'' (DTC 28)
Cooling Fan (Overheat) (Cont'd)
EC-120
Page 158 of 192

EGRC-Solenoid Valve A, B and Throttle Control
Solenoid Valve
SYSTEM DESCRIPTION
Camshaft position sensor (TDC)cEngine speed
ECM
(ECCS-D
control
module)cEGRC-solenoid valve A
Accelerator position sensorcAccelerator positioncEGRC-solenoid valve B
Engine coolant temperature sensorcEngine coolant temperaturecThrottle control solenoid valve
Ignition switchcStart signal
Mass air ¯ow sensor
cAmount of intake air
The ECM receives signals sent from the engine coolant tempera-
ture sensor, crankshaft position sensor (TDC), ignition switch, mass
air ¯ow sensor and accelerator position sensor to determine engine
speed and operating conditions. Based on these signals, the ECM
controls EGR control solenoid valve (A and B) operation and
throttle control solenoid valve operation.
Engine coolant
temperature
ÉC (ÉF)LoadEGRC-solenoid valve
Throttle control
solenoid valveEGR valveThrottle control
valveAmount of EGR
gas
AB
Below 70 (158) AnyOFF
(Closed)OFF
(Closed)OFF
(Closed)Fully closed Fully open Ð
Above 70 (158)Low loadON
(Open)ON
(Open)ON
(Open)Fully open Closed Large
Medium load-1ON
(Open)ON
(Open)OFF
(Closed)Fully open Fully open Medium
Medium load-2ON
(Open)OFF
(Closed)OFF
(Closed)Half open Fully open Small
High loadOFF
(Closed)OFF
(Closed)OFF
(Closed)Fully closed Fully open Ð
COMPONENT DESCRIPTION
The EGRC-solenoid valves A and B control vacuum pressure act-
ing on the EGR valve. The EGR control valve will then be fully
opened, half-opened or fully closed, as required.
The throttle control solenoid valve controls vacuum pressure acting
on the throttle chamber. Thus, intake air passages are opened or
closed in relation to exhaust gas and intake air. Utilizing the rela-
tionship between exhaust gas pressure and intake air pressure
control, the amount of EGR (exhaust gas recirculated) is regulated
in three stages Ð large, medium, small.
SEF784V
TROUBLE DIAGNOSES FOR NON-DETECTABLE ITEMS
EC-156
Page 191 of 192

General Speci®cations
Unit: rpm
Engine RD28ETi
Idle speed 775 25
Maximum engine speed 5,400
Injection pump numbers
Engine Part numberPump assembly
number
RD28ETi 16700 VB300 104721-2000
Injection Nozzle
INSPECTION AND ADJUSTMENT
Injection nozzle assembly
Unit: kPa (bar, kg/cm2, psi)
Initial injection pressure
Used 14,220 (142.2, 145, 2,062)
New14,711 - 15,495 (147.1 - 155.0,
150 - 158, 2,133 - 2,247)
Adjusting shims
Thickness mm (in) Parts No.
0.50 (0.0197) 16613-V0700
0.54 (0.0213) 16613-V0702
0.58 (0.0228) 16613-V0704
0.62 (0.0244) 16613-V0706
0.66 (0.0260) 16613-V0708
0.70 (0.0276) 16613-V0710
0.74 (0.0291) 16613-V0712
0.78 (0.0307) 16613-V0714
0.82 (0.0323) 16613-V0716
0.86 (0.0339) 16613-V0718
0.90 (0.0354) 16613-V0720
0.94 (0.0370) 16613-V0722
0.98 (0.0386) 16613-V0724
1.00 (0.0394) 16613-V0760
Inspection and Adjustment
Plunger lift mm (in)0.92 0.04 (0.0362 0.0016)
(at 9.75É ATDC)
CAMSHAFT POSITION SENSOR (PUMP)
Resistance [at 25ÉC (77ÉF)]W1,360 - 1,840
ENGINE COOLANT TEMPERATURE
SENSOR
Temperature ÉC (ÉF) Resistance kW
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
CONTROL SLEEVE POSITION SENSOR
Resistance [at 23ÉC (73ÉF)]W5.9
SERVICE DATA AND SPECIFICATIONS (SDS)
EC-189