VMAC
– Vehicle Mounted Air Compressors
VMAC Technical Support:
1-888-241-2289
VMAC Knowledge Base: www.kb.vmacair.com
65
Throttle Control Testing
Read the
“Maintenance and Repair Safety” section prior to
performing any work on the system (beginning on Page 38).
Wear appropriate Personal Protective Equipment and follow
all industry standard safety practices.
The air pressure (inlet valve) and engine rpm (throttle actuator) are controlled
by the unloader valve. As air pressure from the unloader valve increases, it
forces the throttle actuator to reduce engine rpm. Once the system has built
to full system pressure (150 psi) the force from the unloader valve will move
the throttle to base idle.
While the system is building air pressure, the PTFE test tool gauge will
indicate 0 psi and the throttle will be wide open. Once downstream pressure
reaches 150 psi it will actuate the unloader valve which opens the discharge
valve. The PTFE test tool gauge will indicate 150 psi and air pressure from
the discharge valve will force the throttle closed. When downstream pressure
drops below 120 psi the discharge valve will close (the PTFE test tool gauge
will indicate 0 psi) and allow the throttle to return to its neutral state of wide
open.
The following testing is for systems set at factory pressure
(150 psi).
With the system off and depressurized:
Remove the WHASP Tank shroud.
Remove the ball valve fitting to accommodate the test tool.
Install a test tool on the system outlet (Figure 51).
Install the PTFE test tool (Figure 43 and Table 6 on page 60) on the 1/4
in throttle tube (Figure 51).
Figure 51
– Test equipment installed
(Scavenge tube not shown)
Throttle actuator
PTFE Test Tool
1/4 in PTFE union
VMAC Air Test
Tool (A700052)
Unloader valve
Discharge valve
1/4 in pressure
control tube
3/16 in pressure
control tube
Summary of Contents for G300003
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