TRUCK SERVICE MANUAL
FUEL SYSTEM
CHECK 4 FUEL GAUGE
Correction
Install new gauge mounts.
Cause
Adjust the adjustable damping valve.
Excessive gauge vibration due to machine vibration
Fig. 6-1-116.
carrying through gauge mounts.
With ST1210 or ST768 Master Injector running in the
Hydraulic pulsations being carried into gauge because of
test stand adjust the needle valve in gauge line until
damping valve not being properly adjusted.
gauge hand flutter is eliminated but gauge hand is
Excessive gauge hand vibration due to improper
responsive to any change in pressure. This adjustment
damping in gauge line.
should be made only with the ST1210 or ST768 Master
Injector and before the machine if calibrated with the
Gauge out of calibration
master.
Check with dead weight tester or a master gauge at 120
Improper plumbing
psi (827 kPa), which is operating pressure. Adjust dial
hand with adjusting screw.
CHECK 5 STROKE COUNTER
Make sure plumbing agrees with Fig. 61121.
Cause
Do not add extra fittings, lines, etc.
Stroke counter improperly set
Correction
Stroke counter engagement faulty
Counter wheels must be set and locked for correct
Stroke counter fails to disengage.
number of strokes; the numbers must then be cleared to
Stroke counter gears damaged or worn.
"O" by rotating with thumb screw for at least one
CHECK 6 AIR SUPPLY
complete revolution.
Cause
Align counter shaft with drive shaft.
Shop air pressure of less than 80 psi (552 kPa).
See Fig. 6-1-122.
Air supply on common line with air actuated equipment
Increase tension on counter return spring at rear of
which causes intermittent pressure drop.
panel.
CHECK 7 AIR SUPPLY GAUGE
Check visually while holding cover back and correct as
Cause
required.
Psi setting does not agree with load test cell reading.
Correction
Air gauge hangs up at a certain point regardless of
Supply air pressure of 80 psi (552 kPa) or more.
regulated pressure.
Rearrange equipment so that ST790 is on a circuit which
Air gauge is erratic; does not repeat consistently when
has constant air pressure.
actuated several times at same pressure.
Correction
Check both air gauge and load test cell when relationship
between gauge and cell changes by more than 3 psi (21
kPa).
Clean, adjust hand to clear face or replace as necessary.
Check inlet for obstruction, gauge hand for hanging up
and correct or replace as necessary.
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