Chevrolet 1980 Light Duty Truck Service Manual page 413

Condition
Engine Cranks Normally -
Will Not Start (C o n t'd )
Engine Starts But Will Not
Continue To Run At Idle
Possible Cause
Pump Timing Incorrect
Glow Plug C ontrol
System Inoperative
Glow Plugs Inoperative
Internal Engine Problems
No Fuel in Tank
Incorrect or
C ontam inated Fuel
Limited Fuel to
Injection Pump
Fuel Solenoid Disengaged
with Ignition Switch in
the " ON" Position
Fig. 6A-3~D iesel Diagnosis
ENGINE M E CHA NICAL
Correction
Make certain th at pum p tim ing mark is
aligned with mark on adapter.
Disconnect wires from one glow plug on
each bank. Use care that disconnected
wires do not ground to chassis. Connect
a 12 volt test lamp in turn from each
glow plug wire to ground. Turn ignition
to " ON" . Test lamp should light while
instrum ent panel lamp signals " DON'T
START" 7
NOTE: Cycle ignition switch to " O FF"
between tests to recycle glow plug
circuitry. If instrum ent panel lamp does
not signal " DON'T START" , engine is
warm; glow plug circuitry is no t called
for; disconnect wire from glow plug
circuit therm istor on intake manifold;
" DON'T STA RT" lamp and glow plug
circuitry will rem ain " ON" for approxi­
m ately 2 m inutes each time ignition is
switched " ON" allowing sufficient time
to conduct test.
If test lamp does not light as outlined
above, refer to Electronics Diagnosis
Section.
Disconnect wire from each glow plug.
With 12 volt test lamp connected to
12 volt source, to uch each glow plug
term inal.
a. If test lamp lights, glow plug
is operational.
b. If test lamp does not light,
replace glow plug or plugs.
Refer to Engine Section 6A.
Install correct fuel in tank.
Flush fuel system and insfall correct fuel.
Test the fuel supply pum p. Replace as
necessary.
Connect a 12 volt test lam p from wire
at injection pum p solenoid to ground.
Turn ignition to " ON" . Lamp should
light. Turn ignition to " START" . Lamp
should light. If lamp does no t light in both
positions, check wiring to solenoid.
6A-9
L IG H T T R U C K SER V IC E M AN UAL