The throttle body is part of the vehicle's air intake system. It is used to
control the amount of air supplied to the engine for combustion.
The throttle body is calibrated at the factory. If there are problems with
the setting of the throttle adjusting screw or with the action, air tightness,
or operation of the throttle, replace the assembly or refer the repair to a
qualified shop.
- Disconnect the negative battery cable.
- Disconnect the accelerator cable from the throttle linkage.
- Unclamp and disconnect the air intake tube from the throttle body.
- Label, then disconnect the vacuum hoses at the throttle body.
- Disconnect the PCV and evaporative control system hoses.
- Detach the throttle position sensor connector.
- Unfasten the nuts from the mounting studs for the throttle body, and remove
it from the air intake surge tank or dynamic chamber (1988–89). Make
sure to remove the gasket(s) and spacer.
To install:
- Using new gasket(s), install the throttle body onto the surge tank or dynamic
chamber. Install and tighten the mounting nuts.
- Attach the throttle sensor connector.
- Connect the PCV and evaporative hoses to the throttle body.
- Connect the air hose and tighten the clamps.
- Connect the accelerator cable and check the cable deflection. Cable deflection
should be 0.04–0.10 in. (1.0–2.5mm). Adjust the throttle sensor
as described later in this section.
- Connect the negative battery cable.
- Disconnect the negative battery cable.
- Drain engine coolant out of the bottom of the radiator (about 2.5 qts.).
- On 1986–87 turbocharged models, unfasten the clamp on the side of
the air funnel, then remove the spark plug wire bracket and position it off
to the side.
- Unclamp and remove the air intake hose or funnel.
- Disconnect the accelerator cable at the actuating cam on the throttle body.
Detach the throttle sensor connector by pulling downward on the locking tab
located underneath.
- On 1986–87 turbocharged models, unfasten the connector from the No.
3 injector.
- Label, then disconnect the vacuum hoses from the upper ports in the throttle
body. Note the connections, then detach the water hoses and air bypass hose.
- Remove the four attaching nuts from the studs and pull the throttle body
off the air surge tank or dynamic chamber (1988–89). On 1986–87
turbocharged models, disconnect the vacuum hose from the lower port of the
throttle body to free the throttle body. Cover the surge tank or dynamic chamber
opening with masking tape to prevent anything from falling into the engine.
To install:
- Install the throttle body onto the air surge tank with the attaching nuts
and a new gasket. On turbo models, connect the vacuum hose to the lower port
first. Tighten the attaching nuts in a crisscross pattern.
- Connect the air bypass, water and vacuum hoses to their respective upper
port connections on the throttle body. On 1986–87 turbocharged models,
fasten the No. 3 injector connector.
- Fasten the throttle sensor connector and the accelerator cable. Connect
the air intake hose or air funnel to the throttle body and tighten the hose
clamps. On turbo models, install the spark plug wire bracket and hose clamp
to the side of the air funnel.
- Connect the negative battery cable and refill the cooling system.
- Adjust the throttle position sensor as described later in this section and
check/adjust the idle speed.
| Fig. 1: Throttle body removal and installation — 1986–87
626
|
