GMC 4000 Series Service Manual page 391

Sec. 6M
Page 380
FUEL INJECTION SYSTEM— TORO-FLOW ENGINE
line to the overflow valve assembly.
11. Thoroughly clean and inspect the fuel lines
to be used in connecting secondary fuel filter.
Mount a new secondary filter on filter bracket and
connect fuel lines. Refer to "Secondary Filter Re­
placement" for any necessary instructions for fuel
line connections.
12. Connect accelerator control linkage and
engine stop mechanism.
CAUTION: The fuel injection nozzles
should be inspected and repaired as nec­
essary, or replaced with new nozzles
whenever a new or rebuilt fuel injection
pump is installed on engine. Attempting
to start an engine having defective injec­
tion nozzles can damage or ruin a fuel
injection pump assembly.
FUEL INJECTION PUMP ASSEMBLY
M a k e ...................................................... Am erican Bosch Arma Corporation
T y p e..................................... PSJ (Single Plunger, with Built-in Governor)
D riv e ................................................................... Gear Train from Crankshaft
Tim ing A d vance..................................................................... Fully Automatic
ENGINE GOVERNED SPEED (RPM)
FULL LOAD
DH-478
Engine Idle S p eed .......................................................................625-675 rpm
Note: Identification plate on pump housing carries GM Part No. and
Mfgr's Number.
OVERFLOW VALVE ASSEMBLY
Regulating Pressure (p s i) (at id le )...................................................... 18-28
Regulating Pressure (p s i) (Gov. sp e ed ).............................................. 40-50
Spring Free Len g th ................................................................................ 1-000"
Spring Pressure % 0 .8 4 0 "......................................................... 414 to 5 lbs.
INJECTION NOZZLE & HOLDER ASSEMBLY
Injection Nozzle Cap N u t..........................................................50-55 ft.-ibs.
High Pressure Fuel Line Nuts (a t Pump & N o zzles)...........20-25 ft.-lbs.
Injection Nozzle B o lts............................................................... 17-20 ft.-lbs.
OVERFLOW VALVE ASSEMBLY
Valve to Body.............................................................................. 20-25 ft.-lbs.
FUEL INJECTION PUMP ASSEMBLY
D elivery Valve R etainer........................................................... 65-70 ft.-lbs.
Delivery Valve Cap N u t.............................................................55-60 ft.-lbs.
G M C S E R V I C E M A N U A L
SPECIFICATIONS
NO LOAD
2800 3050
TORQUE WRENCH SPECIFICATIONS
13. Install high pressure fuel lines referring
to "High Pressure Fuel Line Installation" covered
previously in this section.
14. Prime the fuel system , before attempting
to start engine. Recommended procedure for prim­
ing is given previously under "Priming Fuel Sys­
tem." During priming procedure, the supply line
should remain disconnected from fitting on left
side of pump assembly until all air has been purged
from filters, supply pump, and lines; then continue
to flush fuel through open end of line to avoid the
possibility of any loose particles entering the fuel
chamber surrounding the hydraulic head assembly.
15. Start engine and inspect all fuel line and
lubricating oil line connections for leakage.
16. Check and adjust engine idle speed if re­
quired.
FUEL INJECTION NOZZLE & HOLDER ASSEMBLY
Number and Size of Orifice
DH-478......................................................................................... (4 ) 0.0138"
Valve Opening P ressu re.............................................................. *3000 psi
HIGH PRESSURE LINES
Wall T h ic k n e ss....................................................................................0.083"
Inside D iam eter..................................................................................0.084"
FUEL SUPPLY PUMP
T y p e ......................................................................... Positive Displacement
Location................................................. Rear of Injection Pump Housing
D rive........................................................... From Internal Governor Shaft
Pump Output Pressure (M a x .)......................................................... 65 psi
*With new spring set to 3300 psi.
FUEL INJECTION PUMP ASSEMBLY (Cont.)
Hydraulic Head Fastening S c re w s........................................... 13-15 ft.-lbs.
Governor Cover B o lts..................................................................... 5-6 ft.-lbs.
Control Unit Cover S c re w s....................................................... 2-2!4 ft.-lbs.
Control Unit Plate S cre w s.........................................................P/4-2 ft.-lbs.
Supply Pump Relief Valve S c re w ............................................35-40 ft.-lbs.
Fuel Supply Pump Mounting B o lts ............................................. 5-6 ft.-lbs.
Fuel Supply Pump Insert-to-Cover S c re w s .......................... 2 -2
Injection Pump Mounting Stud N u ts ..................................... 25-30 ft.-lbs.
Vi
ft.-lbs.