Chevrolet 70 1969 Series, Shop Manual

Page: 350 / 913

ENGINE FUEL SYSTEM 6M -23
8. Remove the clevis pin from the fuel rod and
the left bank injector control tube lever.
9. Insert the clevis pin in the fuel rod and the
right cylinder bank injector control tube lever and
position No. 3R injector rack control levers as
previously outlined in step 6 for the No. 3L injec­
tor rack control lever.
10. Insert the clevis pin, the fuel rod and the
left cylinder bank injector control tube lever. Re­
peat the check on the 3L and 3R injector rack con­
trol lever as outlined in step 7. Carefully observe
and eliminate any deflection which occurs at the
bend in the fuel rod where it enters the cylinder
head.
11. Manually hold the No. 3L injector rack in
the F U L L F U E L position and turn down the inner
adjusting screw of the No. 2L injector rack control
lever until the injector rack of the No. 2L injector
has moved into the F U L L F U E L position. Turn the
outer adjusting screw down until it bottoms lightly
on the injector control tube; then alternately tighten
both the inner and outer adjusting screws until they
are tight.
12. Recheck the No. 3L injector rack to be sure
that it has remained snug on the ball end of the
rack control lever while positioning No. 2L injec­
tor rack. If the rack of the No. 3L injector has be­
come loose, back off slightly the inner adjusting
screw on the No. 2L injector rack control lever.
Tighten the outer adjusting screw.
When the settings are correct, the racks of
both injectors must be snug on the ball end of their
respective rack control levers as in step 7.
13. Position the No. 1L injector rack control
lever as outlined in the two steps above.
14. Position No. 2R and 1R injector racks as
outlined above for the left cylinder bank.
15. Turn idle speed adjusting screw in until it
projects 3 /1 6 " from the lock nut to permit starting
of the engine.
16. Replace the engine rocker covers.
L O C A T IN G A MISFIRING C Y L IN D E R
1. Start the engine and run it at part load until
it reaches normal operating temperature.
2. Remove valve cover.
3. Run the engine at idle speed and check the
valve clearance.
4. Hold an injector follower down with a screw­
driver, thus preventing operation of the injector.
If the cylinder has been misfiring, there will be no
noticeable difference in the sound and speed of the
engine. If the cylinder has been firing properly
there will be a noticeable difference in the sound
and operation when the follower is held down. This
procedure is similar to short-circuiting a spark
plug of a gasoline engine.
5. If the cylinder is firing properly, repeat
the procedure on the other cylinders until the
faulty one has been located.
6. If misfiring difficulty is attributed to the
injector, replace injector as described later in this
section.
IN J E C T O R R E M O V A L
Servicing an injector is not a difficult task and
may be performed by the average service man.
However, due to the close tolerances of various
injector parts, extreme cleanliness and strict ad­
herence to service instructions is required.
When servicing injectors, the following in­
structions should be carefully followed:
1. When the fuel pipes are removed from an
injector, cover the filter caps with shipping caps
to keep dirt out of the injector. Also, protect the
fuel pipes and fuel connectors from entry of dirt
or other foreign material.
2. After the injectors have been operated in
an engine, the filter caps or filters should not be
removed while the injectors are in the engine.
Filter elements should be replaced only at the
time of complete disassembly and assembly of an
injector.
3. Whenever an injector has been removed
and reinstalled, or a new injector has been install­
ed in an engine, the following adjustments must be
made as outlined in this section:
a. Time the injector.
b. Position the injector rack control levers.
4. When a reconditioned injector is to be plac­
ed in stock, it should be filled with a quality grade
of rust preventative. Injector test oil J-8130 is
suitable for this purpose. Install shipping caps on
both filter caps immediately after filling. Do not
fill the injector with fuel oil.
N O T E : Make sure that new filters have been
installed in a reconditioned injector which is to be
placed in stock. This precaution will prevent dirt
particles from entering the injector due to a pos­
sible reversal of fuel flow when installing the in­
jector in an engine other than the original unit.
If it becomes necessary to remove one or
more fuel injectors for inspection or replacement,
follow the procedure given below:
1. Remove the valve rocker cover(s).
2. Remove the fuel pipes from both the injec­
tor and the fuel connectors (fig. 6).
N O T E : Immediately after removal of the fuel
pipes from an injector, cover the filter caps with
shipping caps to prevent dirt from entering the in­
jector. Also, protect the fuel pipes and fuel con­
nectors from entry of dirt or foreign material.
3. Crank the engine with the starting motor to
bring the push rod ends - outer ends - of the in­
jector and valve rocker arms in line horizontally.
4. Remove the two rocker shaft bracket bolts
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L