4 - 36 Chapter 4 Fuel and exhaust systems
17.8b Don’t touch MS-2 - this screw, preset at the
factory, establishes the relationship between the throttle
valve and the free lever; if you alter this relationship,
throttle opener and dashpot adjustments won’t be accurate
17.8a if the idle speed isn’t within the specified limits,
readjust it by turning adjusting screw No. 1 (SAS-1)
17.10 if the throttle opener speed is outside the
specified limits, adjust it with the throttle opener
adjusting screw
17.13 Open the throttle valve so the dashpot rod is
extended the full length of its stroke and the free lever
contacts SAS-3
69 if the valve doesn’t operate smoothly, reclean the area around the
valve and apply a thin coat of engine oil.
76 If freeplay is excessive, replace the throttle body.
Port check
71 Connect a hand-operated vacuum pump to each port and check for
clogging of the passages.
72 If any port is clogged, reclean it and blow compressed airinto the port.
17 Carburetor (FBC) (1987 through 1989 models) - adjustments
1 Make sure all lights and accessories are turned off. Place the trans-
mission in Neutral. If the vehicle is equipped with power steering, center
the steering wheel (wheels pointed straight ahead).
2 Hook up a timing light and tachometer in accordance with the man-
ufacturer’s instructions.
3 Start the engine and warm it up to its normal operating temperature.
Idle speed
Refer to illustrafions 17.8a and 7 7.8b
4 Depress the accelerator pedal once to release the fast idle cam.
5 Check the ignition timing. Adjust it if necessary (see Chapter I).
6 Run the engine at idle for two minutes.
7 Note the idle speed and compare your reading with the idle speed
listed in this Chapter’s Specifications.
8 If the idle speed isn’t within the specified limits, readjust it by turning
adjusting screw
No. 1
(SAS-1)
(see illustration). Caution:
Don’t touch
SAS-2 (see i//usfretion). This screw, which is preset at the factory, esta-
blishes the relationship between the throttle valve and the free /ever. If this
relationship is altered, the throttle openeranddashpot adjustments below
won’t be accurate.
Throttle opener (air-conditioned models)
Refer to illustration 17.7 0
Note:
Check and, if necessar): adjust the ignition timing (see Chapter 1)
and idle speed (see above) before doing this aqjustment. Andsee Steps 1
through 3.
9 Turn on the air conditioner switch; this opens the solenoid valve, al-
lowing intake manifold vacuum to actuate the throttle opener. Note what
happens to engine speed when you turn on the switch. It should be within
the range listed in this Chapter’s Specifications.
10 if the engine speed is outside the specified limits, adjust it with the
throttle opener adjusting screw
(see illustration).
Dashpot speed
Refer to illustration 17.13
11 Adjust the idle speed (see above). And see Steps 1 through 3.
12 Start the engine and run it at idle.
13 Open the throttle valve until thedashpot rod is extended the full length
of its stroke and the free lever contacts SAS-3
(see illustration).
14 Close the throttle lever until SAS-2 contacts the free lever and note
the engine speed at that moment of contact. Compare your reading with
the dashpot speed listed in this Chapter’s Specifications.
15 If the dashpot speed isn’t as specified, adjust the dashpot speed by
turning SAS-3.
16 Release the free lever and verify that the engine returns to idle spe&i
slowly.
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