Throttle Body Assembly Removal and Replacement

TBI Assembly Mounting (typical).:

Model 700 TBI:

CAUTION: The throttle bore and valve deposits may be cleaned on the vehicle, using carburetor cleaner and a parts cleaning brush. Do Not use a cleaner that contains Methyl Ethyl Ketone. It is an extremely strong solvent, and not necessary for this type of deposit.
^ The throttle body parts may be cleaned following disassembly, in a cold immersion type cleaner such as GM X-55 or equivalent.
^ The throttle position sensor (TPS) and idle air control (IAC) valve should not come in contact with solvent or cleaner, as they are electrical components and may be damaged.


REMOVAL:

1. Relief fuel pressure. Service and Repair
2. Disconnect the negative battery cable.
3. Remove fuel feed and return lines. Use a backup fuel line wrench on the TBI fuel nuts to prevent them from turning.
4. Remove and discard the fuel line O-rings.
5. Disconnect the IAC valve and TPS electrical connectors.
6. Disconnect the vacuum lines.
7. Disconnect the throttle, T.V, (transmission control), and cruise control cables.
8. Remove the throttle body attaching bolts.
9. Remove the throttle body assembly and flange gasket, discard the gasket.
10. Clean the gasket sealing surfaces:
^ Use care in cleaning old gasket material from machined aluminum surfaces. Sharp tools may damage sealing surfaces.


INSTALLATION:

1. Install the throttle body assembly with a new flange gasket.
2. Install the throttle body attaching bolts and tighten to 25 Nm (18 lb. ft.).
3. Install new O-rings on fuel lines.
4. Install fuel lines and tighten to 27 Nm (20 lb. ft.). Use backup fuel line wrench on the TBI fuel nuts to prevent them from turning.
5. Connect the throttle, T.V., and cruise control cables.
NOTE: Make sure that the throttle and cruise control cables do not hold the throttle open.
6. Connect the vacuum lines.
7. Connect the IAC and TPS electrical connectors.
8. Connect the negative battery cable.
9. With the engine OFF, check to see that the accelerator pedal is free, depress the accelerator pedal to the floor and release.
10. Start engine and check for leaks.