4 X 2 Gear Selector
24
5.9. If a vacuum gauge is connected by T-fitting at
the reservoir (accumulator) end of the vacuum
line from the intake manifold, the following
readings should occur: See Figure
5.9.
• Idle speed: pulsing needle 7 - 18 in. HG.
• 2500 RPM: steady between 15 - 22 in. HG.
(usually 17 - 18 in. HG.)
• Over-run: highest reading > 30 in. HG.
• Engine Off: vacuum falls to 0.
NOTE: If the vacuum level is low, it may be an
engine problem such as low compression or a
blocked exhaust system.
NOTE: If there are no engine problems and the
vacuum is low, the most common cause will be
leaky vacuum lines or fittings. To check for this,
dead-head the vacuum gauge to the line leading
to the manifold. If the vacuum level improves,
there are leaks in the system.
5.10. If a vacuum gauge is connected by T-fitting to
the line that leads from the accumulator to
the solenoid valves, the following readings
should occur: See Figure 5.10.
• Idle speed: steady needle 15”-22” HG.
(usually 17”-18” HG.)
• 2500 RPM: steady needle 15”-22” HG.
(usually 17”-18” HG.)
• Over-run: steady needle 15”-22” HG.
(usually 17”-18” HG.)
Engine Off: vacuum will slowly bleed down to 0 over
the course of 10 - 15 minutes. In this time it will be pos-
sible to shift gear several times until the vacuum level
falls below about 7” HG. See Figure 5.10.
Figure 5.9
Pulsing needle at idle
Figure 5.10
Steady needle at idle
Figure 5.10
vacuum after the engine is stopped
Maintains several shifts worth of
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