TM 5-3810-307-24-1-2
d.
Slowly decrease the remote throttle pressure. The needle in the throttle valve (needle
block) should start to open allowing fuel to flow from the fuel tank, through the throttle
valve (needle block), and out the removed fuel injector line. The fuel should flow freely
with the remote throttle at zero pressure (0 psi).
e.
Increase the throttle pressure again. The fuel should gradually diminish as remote
throttle pressure increases and then completely shutoff at 550 psi (38 bar).
f.
If the fuel system does not operate as described above, the problem is the throttle valve
(needle block), remote throttle, fuel pump and/or fuel injectors. Perform the Throttle
Valve (Needle Block) Test to isolate the problem.
g.
If the fuel system operates as described above, the throttle valve (needle block) is OK
and the problem is with the fuel pump and/or fuel injector(s). Perform the Fuel Pump
Inlet/Outlet Check Valve Test to isolate the problem.
h.
Reconnect the fuel injector line.
Throttle Valve (Needle Block) Test
The Throttle Valve (Needle Block) Test should be performed if the fuel system did not operate as
described in the above Throttle Valve (Needle Block) and Fuel Pump Test.
Test Procedure.
a.
Remove the throttle valve (needle block) from the lower cylinder of the impact hammer
and the fuel tank return line. Leave the hydraulic line from the remote throttle
connected.
b.
Remove the outlet elbow fitting on the throttle valve (needle block).
c.
The throttle needle stem is visible inside the fuel outlet port. It should move smoothly
and seat completely at 550 psi (38 bar).
d.
If the throttle valve (needle block) operates as described above, the problem is the fuel
pump and/or fuel injectors. Perform the Fuel Pump Inlet/Outlet Check Valve Test to
isolate the problem.
e.
If the throttle valve (needle block) does not operate as described above, the problem is
the throttle valve (needle block) and/or remote throttle. Perform the troubleshooting
steps listed in the throttle valve (needle block) section and remote throttle Table K-7.
Place Loctite 545 (purple) on the outlet elbow fitting. Reinstall the outlet elbow fitting in
f.
a functional throttle valve (needle block). Reinstall the throttle valve (needle block).
Change-1 K-33
