TM 10-4320-307-24
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HVT VALVE ASSEMBLY TEST/REPAIR/REPLACE (CONT).
3.
Operate engine at idle.
4.
Bleed gauge line of air.
5.
Check gauge reading.
a.
If oil pressure is less than 20 psi (138 kPa), the HVT valve is in normal (retarded) mode. Check for voltage at
HVT valve. If voltage is present, check for oil leaks at oil connections in rocker housings. If there are no oil
leaks, replace valve.
b.
If voltage is not present at HVT valve, check fuel pressure switch.
c.
If oil pressure is more than 20 psi (138 kPa), the HVT valve is in advanced mode. Remove wire from HVT
valve.
d.
If oil pressure does not decrease, check resistance across the two terminals of HVT valve. If resistance is not
between 28 and 32 ohms, the solenoid must be replaced.
e.
If oil pressure did not decrease and solenoid resistance is not as specified in step d, replace HVT valve.
REMOVAL:
1.
Remove screw (1), lockwasher (2). and tube clamp
(3) securing supply tube (4) and O-ring seal (5) to
cylinder head.
2.
Remove supply tube (4) from male union elbow (6).
3.
Remove male union elbow (6) from shutoff valve body
(7).
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