Ccc Component Removal & Installation Chevrolet Forward Control P30

Turn ignition switch off. Disconnect negative battery cable from battery. Locate ECM and remove access panels, if any. Remove electrical connectors from ECM. Remove ECM from vehicle. Remove PROM and CALPAC (if equipped) from ECM.

Install PROM (and CALPAC) on new ECM. Reinstall ECM into vehicle. Reconnect electrical connectors to ECM. Install right hand hush panel. Reconnect negative battery cable to battery.

1. Remove ECM from vehicle as previously described. Position ECM so that bottom cover is facing upward. Remove and slide-off PROM access cover by depressing locking tab.
2. Using PROM removal tool, grasp the PROM at the narrow ends. Gently rock the PROM from end to end while pulling up on PROM. Remove PROM from PROM carrier.

Note. Note the location of the reference notches in the PROM and the ECM for reassembly reference.

Replacing PROM in Electronic Control Module Always use PROM removal tool when replacing PROM. Scheme 1

1. Check that new PROM has the same service number as the old one. Place the new PROM in the ECM. Position the PROM carrier squarely over the PROM. Press on the PROM carrier until the PROM is firmly seated in the ECM. NOTE: Make sure that the reference notches in both the ECM and the PROM are properly aligned.
2. Reinstall PROM access cover on ECM. Reinstall ECM in vehicle as previously described. Start engine and ground diagnostic test lead. Watch for trouble Code 51.
3. If this occurs, PROM is not fully seated in ECM, installed backwards, has bent pins or is defective. If pins are bent and crack when straightened, PROM must be replaced. If PROM is installed backwards or is defective, it must be replaced.

Some ECM models use a CALPAC as well as a PROM. The CALPAC must be removed from the replaced ECM and installed in the new one. Removal and replacement procedures for the CALPAC are the same as for the PROM. Grounding diagnostic test lead will set Code 52.

View of ECM With PROM & CALPAC Replacement procedures are the same for both components. Scheme 2

Disconnect negative battery cable at battery. Raise vehicle on hoist. Disconnect electrical connector from oxygen sensor. Carefully remove oxygen sensor from exhaust pipe.

Note. Oxygen sensor may be difficult to remove when engine temperature is below 120°F (49°C). Excessive removal force may damage threads in exhaust manifold or pipe.

1. Whenever an oxygen sensor is removed, its threads must be coated with anti-seize compound before it is reinstalled. New oxygen sensors will already have this compound applied to threads.
2. Install oxygen sensor in exhaust pipe and tighten to 30 ft. lbs. (41 N.m). Reconnect electrical connector to oxygen sensor. Lower vehicle from hoist. Reconnect negative battery cable to battery.

Remove air cleaner assembly. Disconnect electrical connector from TPS. Remove 2 TPS attaching screws, lockwashers and retainers. Remove TPS.

1. With throttle valve in normal closed idle position, install TPS on throttle body. Make sure that TPS lever is located above tang on throttle actuator lever.
2. Apply thread locking compound to TPS screws. Install TPS screws with lock washers and retainers. Reconnect electrical connector to TPS.

Adjustment

DO NOT attempt to adjust the TPS on models equipped with TBI 1.8L and 2.5L engines. The TPS supplies the ECM with a variable voltage. If the TPS voltage is less than 1.25 volts at the idle position, replace TPS.

1. Disconnect M/C solenoid, TPS and idle speed solenoid electrical connectors.
2. Remove the carburetor air horn assembly as follows: Remove air horn attaching screws and idle speed solenoid. Remove upper choke lever from end of choke shaft by removing retaining screw. Rotate upper choke lever to remove choke rod from slot in lever. Remove choke rod from lower lever inside float bowl casting. Remove rod by holding lower lever outward with small screwdriverand twisting rod counterclockwise. Remove retainer from pump link, link from pump lever. Do not remove pump lever from air horn. Disconnect front vacuum break hose from tube on float bowl. Remove air horn-to-bowl screws; then remove two countersunk attaching screws located next to venturi. Lift air horn straight up and off of float bowl.
3. Lift air horn gasket from dowel locating pins on float bowl. Discard gasket.
4. TPS is staked in place in bowl. Remove staking as follows: Lay a flat tool or metal piece across bowl casting to protect gasket sealing surface. Use a small screwdriver to depress TPS sensor lightly and hold against spring tension. Use a small chisel (or equivalent) to pry staking upward, making sure prying force is exerted against the metal tool and not against the bowl casting. Push up from bottom on electrical connector to remove TPS and connector assembly from bowl.

Scheme 3

1. Install TPS and connector assembly in float bowl by aligning groove in electrical connector with slot in float bowl casting. Push down on connector and sensor assembly so that connector and wires are located below bowl casting surface. Be sure Green TPS actuator plunger is in place in air horn.
2. Install air horn gasket, holding pump plunger assembly down against return spring tension and aligning pump plunger stem with hole in gasket. Align holes in gasket over TPS plunger, solenoid plunger return spring, metering rods, solenoid attaching screw and electrical connector. Position gasket over two dowel locating pins on float bowl.
3. Install solenoid-metering rod plunger, holding down on air horn gasket and pump plunger assembly, and aligning slot in end of plunger with solenoid attaching screw.
4. Carefully lower air horn assembly onto float bowl while positioning TPS adjustment lever over TPS, and guiding pump plunger stem through seal in air horn casting. To ease installation, insert a thin screwdriver between air horn gasket and float bowl to raise TPS adjustment lever, positioning it over the sensor.
5. Install air horn screws and lockwashers, and two countersunk screws (located next to carb. venturi on 4-bbl. models). Tighten all screws evenly and securely, following air horn screw tightening sequence. (Scheme 3): Air Horn Screw Tightening Sequence
6. Install front vacuum break and bracket assembly on air horn, using two attaching screws. Install pump link to pump lever and insert retainer pin.
7. Install choke rod into lower choke lever inside bowl cavity. Install choke rod in slot in upper choke lever, and position lever on end of choke shaft (make sure flats on end of shaft align with flats in lever). Install attaching screw and tighten securely. When properly installed, lever will point to rear of carburetor, and number on lever will face outward.
8. Install M/C solenoid, TPS and idle speed solenoid electrical connectors. Clear trouble code memory and check TPS voltage. Voltage reading, with A/C off and throttle at curb idle position, should be.26 volts for V6 models, or.41 volts for V8s.

1. If voltage reading in step 8) of installation procedure is incorrect, TPS must be adjusted.
2. Remove tamper-resistant plug covering adjustment screw. Using a 5/64" drill, drill a 1/16" to 1/8" deep hole in plug. Use care in drilling to prevent damage to adjustment screw head.
3. Start a No. 8, 1/2" long self-tapping screw in drilled hole turning screw in only enough to ensure good thread engagement in hole.
4. Placing a wide-blade screwdriver between screw head and air horn casting, pry against screw head to remove plug. Discard plug. Remove TPS adjustment screw with TPS adjustment tool (J-28696).
5. Disconnect TPS connector and jumper all three terminals. Connect digital voltmeter from TPS connector center terminal "B" to bottom terminal "C". Reinstall TPS adjustment screw. With ignition on (engine off), quickly adjust screw to obtain correct TPS voltage.
6. After adjustment, install new tamper-resistant plug (supplied in service kits) in air horn. Drive plug into place until flush with raised pump lever boss on casting. Clear trouble code memory after adjustment.

Removal of all other sensors, switches and solenoids is accomplished by removing the electrical and/or vacuum connectors and removing or detaching the component.