EMISSION CONTROLS AND FUEL SYSTEM 179
installed alongside the fuel injector (one screw
each side).
13. For the rear TBI unit only: With the
throttle valve in the closed (idle) position, in
stall the TPS but do not tighten the attaching
screws. The TPS lever must be located
ABOVE the tang on the throttle actuator
lever.
14. Install the TBI unit(s) as previously
outlined and adjust the throttle position sen
sor.
ADJUSTMENTS
No internal adjustments of the TBI units are
possible. Any time the TPS is removed, it
must be readjusted according to the follow-
ing procedure.
Throttle Position Sensor (TPS)
Adjustment
NOTE:
An accurate digital voltmeter is
needed to perform this adjustment.
1.
Remove the TPS attaching screws and
apply thread locking compound to the screws.
Reinstall the screws loosely.
2. Install three jumper wires between the
TPS and the TPS wiring terminal connec
tions, as shown in the accompanying illustra
tion.
3. Turn the ignition ON and measure the
voltage between the A and B terminals of the
TPS. Rotate the TPS to obtain a voltmeter
reading of .525+.075 volts. Tighten the
screws.
4. Turn the ignition OFF, remove the
jumpers, and connect the TPS wiring to the
TPS.
1982-84 THROTTLE BODY INJECTION
Minimum (die and Throttle Valve
Synchronizing
The throttle position of each throttle body
must be balanced so that the throttle plates
are synchronized and open simultaneously.
Adjustment should be performed only when
a manifold cover, TBI unit or throttle body
has been replaced.
1. Remove the air cleaner and plug the
vacuum port on the rear TBI unit for the
thermostatic air cleaner.
2. Remove the tamper resistant plugs
covering both unit throttle stop screws. Make
sure both throttle valves are slightly open to
allow fuel to bypass them.
3. Block the drive wheels and apply the
parking brake.
4. Connect a tachometer to measure rpm.
5. Disconnect the idle air control (LAG)
valve electrical connectors.
6. Plug the idle air passages of each
throttle body with plugs (J-33047 or equiva
lent). Make sure the plugs are seated fully in
the passage so that no air leaks exist.
CAUTION:
To prevent the engine from
running at high rpm, be sure the ignition
switch is OFF and transmission is in NEU-
TRAL before connecting IAC valves or re-
moving or installing idle air passage plugs.
Failure to do this may result in vehicle
movement and possible personal injury.
7. Start the engine and allow the engine
rpm to stabilize at normal operating temper
ature.
8. Place the transmission in DRIVE while
Throttle position sensor adjustment—see text
