Height Control Valve Test-On Car Exhaust (Superlifts Inflated); Time Delay Check; Installing Piston Seal; Filling System Through Service Valve - Pontiac Grand Prix Service Manual

REAR SUSPENSION 4-17
Fig. 4.23 Installing Piston Seal
NOTE: If available pressure is less than 140 psi, start
engine to build-up reservoir to this pressure.
3. Regulated pressure should build-up to and hold
steady at 100-130 psi on test gage.
4. Check regulated pressure by momentarily (not more
than one second) depressing valve core on test gage
and observe gage reading.
5. If regulated pressure now reads less than 100 psi,
replace regulator assembly.
6. If regulated pressure exceeds 130 psi, replace
regulator assembly.
HEIGHT CONTROL VALVE TEST--ON CAR
EXHAUST (SUPERLIFTS INFLATED)
1. Discon~lect overtravel lever from link.
4.
If Superlifts inflate and then leak down, perform
leak test on lines and fittings and then on Superlifts.
Also check and, if necessary, replace HCV intake and
exhaust screens and O-rings. If Superlifts still do not
inflate, perform leak test on valve. Repair as indicated
and proceed to TPME DELAY CHECK.
TIME DELAY CHECK
1. Disconnect overtravel lever from link.
2. Disconnect lines at Superlift and intake port.
3. Connect test gage to intake valve port and open air
pressure (95 psi). Move overtravel lever approximately
one inch down from neutral position, as measured
from end of lever.
4. Quickly move overtravel lever upward two inches; at
the same time, begin timing number of seconds before
air starts to escape from Superlift port. This' delay
should be from 4-18 seconds. Repeat check. This will
check the air intake time delay. Proceed with check to
determine air exhaust time delav.
5. Remove test gage and plug intake port with Fill
Valve.
4
6. Connect test gage to Superlift port and open air
pressure (95 psi). Move overtravel lever approximately
one inch up from neutral position, as measured from
end of lever.
7. Quickly move overtravel lever downward two
inches; at the same time, begin timing number of
seconds until air begins to escape from exhaust port.
This delay should be 4- 18 seconds. Repeat check.
If either delay is not within specification, there has
DELAY
HECK.
Fig. 4-24 Filling System through Service Valve